
1999 Neurontin Research for Off-Label Purposes
Updated 7/27/01

J Affect Disord 1999 Oct;55(2-3):237-40
Open maintenance treatment of bipolar disorder spectrum patients who responded
to gabapentin augmentation in the acute phase of treatment.
Schaffer CB, Schaffer LC Department of Psychiatry, UC
Davis School of Medicine, Sacramento, CA 95816, USA.
This report describes the results of maintenance
treatment with gabapentin in 18 previously refractory Bipolar Disorder patients who
initially responded to augmentation with gabapentin during the acute phase of their
therapy. Seven of the original 18 patients (39%) have continued to experience benefit from
maintenance gabapentin treatment. Only three patients had to discontinue the gabapentin
because of side effects. None of the 18 patients experienced an obvious significant
adverse drug-drug interaction. Five of the patients discontinued gabapentin because of
diminished clinical efficacy after a significant period of positive therapeutic effect.
The results of this small open study suggest that gabapentin may be effective as an
augmenting agent in the maintenance phase of treatment of some bipolar spectrum patients.
Ther Drug Monit 1999
Dec;21(6):615-7
A case of sustained massive gabapentin overdose without
serious side effects. Verma A, St Clair EW, Radtke RA Department of Medicine, Duke
University Medical Center, Durham, North Carolina, USA.
Gabapentin is an antiepileptic agent that is indicated
for use as adjunctive therapy for partial seizures. It has a relatively benign side effect
profile, but little data exists on massive overdoses with this agent. The authors present
a case of a patient who received a massive overdose of this agent but suffered no
clinically significant toxicity.
Pharmacopsychiatry 1999
Nov;32(6):255-7
Gabapentin leads to remission of somatoform pain
disorder with major depression. Maurer I, Volz HP, Sauer H Department of Psychiatry,
Friedrich-Schiller-Universitat Jena, Germany. maurer@landgraf.med.uni-jena.de
Gabapentin, a novel antiepileptic drug, is effective in
the treatment of partial seizures with and without secondary generalization. Evidence
suggests that it may have mood-stabilizing and possibly antidepressant properties in
bipolar depression. We report on a 48-year-old woman who had recurrent major depressive
disorder. Following inguinal herniorrhaphy, she developed severe stabbing pain in the
lower abdomen and inguinal area that progressed to constant pain in her whole body. She
was depressive, hopeless, and had given up her social activities. A diagnosis of major
depressive disorder and somatoform pain disorder was made. Antidepressants and
carbamazepine were ineffective, and she had attempted suicide. Gabapentin resulted in
remission of both the pain and the depressive mood at a dose of 1.800 mg/day
. Ann Clin Psychiatry 1999 Dec;11(4):217-22
Gabapentin as an adjunct to standard mood stabilizers in
outpatients with mixed bipolar symptomatology.
Sokolski KN, Green C, Maris DE, DeMet EM Mental Health
Care Group, Veterans Affairs Medical Center, Long Beach, California 90822, USA.
Gabapentin is a new adjunctive medication to antiseizure
therapies. Anecdotal evidence suggests that it may also help to alleviate mood symptoms in
patients with bipolar illness. An open-label study examined the effects of adjunctive
gabapentin in bipolar patients with mixed symptoms who had previously demonstrated only
partial treatment responses. Mood ratings and side-effect profiles were followed weekly in
10 patients for 1 month. Decreases in Hamilton depression (P < 0.05) and Bech mania
ratings (P > 0.01) were evident in the first week of treatment and were sustained.
Potent early improvements were noted in early, middle, and late insomnia. The results
suggest that gabapentin may be of benefit to bipolar patients who only partially respond
to other mood stabilizers. A favorable side-effect profile and rapid action make this drug
an attractive choice as an adjunctive therapy.
J Am Dent Assoc 1999
Oct;130(10):1467-9
Antidepressant-induced bruxism successfully treated with
gabapentin. Brown ES, Hong SC Department of Psychiatry, University of Texas Southwestern
Medical Center, Dallas 75235-9101, USA.
BACKGROUND: Symptoms consistent with bruxism are a
common chief complaint in dental practice. The authors describe a case of bruxism likely
induced by the antidepressant venlafaxine and successfully treated with gabapentin. CASE
DESCRIPTION: A case of bruxism, anxiety, insomnia and tremor is reported in a man with
bipolar disorder that developed a few days after he initiated venlafaxine therapy for
depression. The patient's psychiatrist prescribed gabapentin for anxiety symptoms, and
shortly thereafter the man experienced a complete resolution of the bruxism. CLINICAL
IMPLICATIONS: On the basis of this case and the available literature, the authors conclude
that bruxism secondary to antidepressant therapy may be common. Thus, dentists should
inquire about the use of these medications in patients who have bruxism. Gabapentin may
offer promise in the treatment of this condition.
Am J Health Syst Pharm 1999 Oct
1;56(19):1939-44
Gabapentin and lamotrigine in bipolar disorder.
Botts SR, Raskind J College of Pharmacy and Allied
Health Professions, St. John's University, Jamaica, NY 11439, USA. Botts@lij.edu
The utility of gabapentin and lamotrigine for the
treatment of bipolar disorder is reviewed. Bipolar disorder is characterized by extreme
mood fluctuations, including mania, hypomania, depression, and mixed episodes.
Extrapolation of postulated mechanisms of anticonvulsant activity in bipolar disorder has
led to the use of the newer anticonvulsants gabapentin and lamotrigine for therapy. Both
agents appear promising on the basis of limited (often anecdotal) evidence. They may prove
effective in patients with difficult cases of bipolar disorder, such as patients with
rapid cycling, mixed episodes, and illness refractory to other treatments. Lamotrigine may
offer a much-needed treatment alternative for bipolar depression and could be found
effective for acute mania, but the need for slow dosage adjustment and the risk of rash
may limit overall clinical utility. Gabapentin may offer significant advantages for acute
mania: The dosage can be adjusted rapidly, adverse effects are generally minimal, the
therapeutic index is high, there is no required laboratory monitoring, and there is
minimal potential for interactions with other psychotropics. Until the results of
randomized controlled trials are known, however, these two agents should be reserved for
patients with bipolar disorder unresponsive to traditional therapies and for patients who
cannot tolerate traditional agents. Preliminary evidence indicates that gabapentin and
lamotrigine may be useful for the treatment of bipolar disorder.
Eur Neuropsychopharmacol 1999 Aug;9
Suppl 4:S113-7
Lamotrigine in the treatment of bipolar depression.
Bowden CL, Mitchell P, Suppes T Department of
Psychiatry, University of Texas, Health Science Center at San Antonio, 78284-7792, USA.
Several case reports and open studies have reported the
efficacy of lamotrigine in bipolar depression. A randomised placebo-controlled 7-week
study comparing two doses of lamotrigine with placebo in 195 patients with moderate to
severe bipolar depression has now been completed. Lamotrigine was superior to placebo
after 3 weeks as assessed by changes in the Montgomery-Asberg Depression Rating Scale
(MADRS). A response, defined as more than 50% improvement on the MADRS occurred in 56 and
48% of the lamotrigine 200 and 50 mg/day groups, respectively, compared with 29% for
placebo (P<0.05). There was no evidence that lamotrigine destabilised mood or
precipitated mania. Tolerability was good and there were no cases of serious rashes.
Preliminary results from an ongoing study also indicate that lamotrigine is more effective
than gabapentin in bipolar depression. In conclusion, lamotrigine is effective in
alleviating bipolar depression, without causing mood destabilisation. Slow dosage
escalation yields good tolerability.
Semin Pediatr Neurol 1999
Sep;6(3):182-8; discussion 189
An 8-year-old girl with unilateral facial and ear pain
and isolated frontal headaches.
Gay CT Department of Neurology, University of Oklahoma
Health Sciences Center, Oklahoma City, USA.
An 8 1/2-year-old with chronic but fluctuating
unilateral facial pain, earache, frontal headache and facial swelling is presented. Her
journey through the health care system provides an instructional lesson for all who deal
with patients with unusual or difficult to recognize conditions.
J Affect Disord 1999
Sep;55(1):73-7
Gabapentin as an adjunctive treatment in bipolar
disorder.
Young LT, Robb JC, Hasey GM, MacQueen GM, Patelis Siotis
I, Marriott M, Joffe RT Department of Psychiatry, McMaster University, Hamilton, Ontario,
Canada. youngt@fhs.mcmaster.ca
OBJECTIVE: To evaluate the efficacy of gabapentin as an
adjunctive treatment for bipolar disorder in both depressed and manic phases. METHOD:
Thirty seven patients with bipolar type I or II with or without a rapid cycling course
were openly treated with gabapentin added to current treatment for up to six months. Mood
symptoms were rated weekly for 12 weeks then monthly for 3 months utilizing the HamD and
YMS. RESULTS: Participants experienced a significant reduction in both depressive and
manic symptoms. CONCLUSIONS: These findings are consistent with others in establishing the
efficacy of gabapentin in both phases of bipolar disorder. LIMITATIONS: Small sample size
and the use of an open uncontrolled design limit interpretation of results.
Can Fam Physician 1999
Sep;45:2109-12
Using gabapentin to treat neuropathic pain.
Hays H, Woodroffe MA
OBJECTIVE: To review use of gabapentin as an adjuvant
agent to treat neuropathic pain. QUALITY OF EVIDENCE: MEDLINE was searched from 1995 to
October 1998 for reports. There were approximately 20 citations. Additional articles from
Pain and other medical journals were reviewed. No double-blind studies have examined
gabapentin and its use as an analgesic adjuvant agent. MAIN MESSAGE: Gabapentin is an
anticonvulsant medication used recently as an effective adjuvant agent for treating
neuropathic pain. It is a structural analogue of gamma-aminobutyric acid (GABA), but its
receptor and biochemical function remain unknown. Gabapentin has desirable pharmacokinetic
properties and acceptable side effects, which simplify its use. There are very few
interactions between gabapentin and other medications, and gabapentin is well tolerated.
CONCLUSION: Gabapentin could be an effective adjuvant agent for many neuropathic pain
states.
Arch Intern Med 1999 Sep
13;159(16):1931-7
Randomized double-blind study comparing the efficacy of
gabapentin with amitriptyline on diabetic peripheral neuropathy pain.
Morello CM, Leckband SG, Stoner CP, Moorhouse DF,
Sahagian GA Veterans Affairs San Diego Healthcare System, Calif 92161, USA.
BACKGROUND: Reports of gabapentin use in diabetic
peripheral neuropathy pain stimulate a need for controlled trials to determine its
comparative efficacy to the therapeutic standard of amitriptyline hydrochloride.
OBJECTIVE: To determine the efficacy of gabapentin compared with amitriptyline in treating
diabetic peripheral neuropathy pain. DESIGN: Prospective, randomized, double-blind,
double-dummy, crossover study. SETTING: Veterans Affairs San Diego Healthcare System,
Ambulatory Care Clinic. PATIENTS: Twenty-eight veterans were referred by their primary
care providers. Two patients withdrew before randomization because of no neuropathic pain
after washout; a third withdrew for unexpected surgery that required analgesics. Three
patients withdrew because of adverse effects and 1 for protocol violation. INTERVENTIONS:
Patients with stable glycemic control and neuropathic pain randomized to 6 weeks of
therapy with gabapentin, 900 to 1800 mg/d, or amitriptyline hydrochloride, 25 to 75 mg/d,
with a 1-week washout before crossover. MAIN OUTCOME MEASURES: Pain relief measured by
pain scale with verbal descriptors and global pain score assessment at treatment end.
RESULTS: Participants and investigators were blinded throughout. Mean dosages were of
gabapentin, 1565 mg/d, and of amitriptyline hydrochloride, 59 mg/d. Sixty-five percent of
patients reached maximum dose with gabapentin and 54% with amitriptyline. Mean score diary
analysis showed pain relief with gabapentin and amitriptyline was not significantly
different (P = .26). Global data were obtained from 21 of 25 enrolled patients who
completed the study. Moderate or greater pain relief was experienced in 11 (52%) of 21
patients with gabapentin and 14 (67%) of 21 patients with amitriptyline. There were no
significant period or carry-over effects (P = .35). CONCLUSIONS: Although both drugs
provide pain relief, mean pain score and global pain score data indicate no significant
difference between gabapentin and amitriptyline. Gabapentin may be an alternative for
treating diabetic peripheral neuropathy pain, yet does not appear to offer considerable
advantage over amitriptyline and is more expensive. Larger trials are necessary to define
gabapentin's place in treating diabetic peripheral neuropathy pain.
Epilepsia 1999 Sep;40(9):1279-85
Differential cognitive effects of carbamazepine and
gabapentin.
Meador KJ, Loring DW, Ray PG, Murro AM, King DW, Nichols
ME, Deer EM, Goff WT Department of Neurology, Medical College of Georgia, Augusta 30912,
USA. KMEADOR@NEURO.MCG.EDU
PURPOSE: The cognitive effects of the newer
antiepileptic drugs (AEDs) compared with the older standard AEDs are uncertain. METHODS:
We directly compared the cognitive effects of carbamazepine (CBZ) and gabapentin (GBP) in
35 healthy subjects by using a double-blind, randomized crossover design with two 5-week
treatment periods. During each treatment condition, subjects received either GBP, 2,400
mg/day, or CBZ (mean, 731 mg/day) adjusted to a dose to achieve midrange standard
therapeutic blood levels (mean, 8.3 microg/ml). Subjects were tested at the end of each
AED treatment period and in four drug-free conditions [two pretreatment baselines and two
post-treatment washout periods (1 month after each AED)]. The neuropsychological test
battery included 17 measures yielding 31 total variables. RESULTS: Direct comparison of
the two AEDs revealed significantly better performance on eight variables for GBP, but
none for CBZ. Comparison of CBZ and GBP to the nondrug average revealed significant
statistical differences for 15 (48%) of 31 the variables. Pairwise follow-up analyses of
the 15 variables revealed significantly better performance for nondrug average on 13
variables compared with CBZ, and on four compared with GBP. GBP was better than nondrug
average on one variable. CONCLUSIONS: Although both CBZ and GBP produced some effects, GBP
produced significantly fewer untoward cognitive effects compared with CBZ at the dosages
used in this study.
J Affect Disord 1999
Aug;54(3):315-7
Gabapentin as a promising treatment for
antipsychotic-induced movement disorders in schizoaffective and bipolar patients.
Hardoy MC, Hardoy MJ, Carta MG, Cabras PL Institute of
Psychiatry, University of Cagliari, Italy. ugolini@tin.it
Improvement of antipsychotic-induced blepharospasm and
involuntary oral-mandibulo movements was observed with the use of the anticonvulsant drug
gabapentin among 14 of 16 affectively ill patients who had been exposed to maintenance
neuroleptics of the conventional type. In many cases, the movement disorders of these
patients had not responded to more standard measures such as clozapine. This finding
permits a potential strategy for patients with treatment-emergent tardive dyskinesia, a
well-known complication of extended conventional neuroleptic use. Gabapentin, whose mood
stabilizing properties have been reported in several clinical reports, represents a more
natural treatment in the setting of bipolar spectrum disorders.
J Clin Psychopharmacol 1999 Aug;19(4):341-8
Treatment of social phobia with gabapentin: a
placebo-controlled study.
Pande AC, Davidson JR, Jefferson JW, Janney CA,
Katzelnick DJ, Weisler RH, Greist JH, Sutherland SM Parke-Davis Pharmaceutical Research,
Division of Warner-Lambert Company, Ann Arbor, Michigan 48105, USA. atul.pande@wl.com
A randomized, double-blind, placebo-controlled,
parallel-group study was conducted to evaluate the efficacy and safety of gabapentin in
relieving the symptoms of social phobia. Sixty-nine patients were randomly assigned to
receive double-blind treatment with either gabapentin (dosed flexibly between 900 and
3,600 mg daily in three divided doses) or placebo for 14 weeks. A significant reduction (p
< 0.05) in the symptoms of social phobia was observed among patients on gabapentin
compared with those on placebo as evaluated by clinician- and patient-rated scales.
Results were similar for the intent-to-treat and week-2 completer populations. Adverse
events were consistent with the known side effect profile of gabapentin. Dizziness (p =
0.05), dry mouth (p = 0.05), somnolence, nausea, flatulence, and decreased libido occurred
at a higher frequency among patients receiving gabapentin than among those receiving
placebo. No serious adverse events or deaths were reported. On the basis of these limited
data, it seems that gabapentin offers a favorable risk-benefit ratio for the treatment of
patients with social phobia. Further studies are required to confirm this effect and to
determine whether a dose-response relationship exists.
PMID: 10440462, UI: 99367074
Epilepsia 1999 Aug;40(8):1129-34
A beneficial effect on mood in partial epilepsy patients
treated with gabapentin.
Harden CL, Lazar LM, Pick LH, Nikolov B, Goldstein MA,
Carson D, Ravdin LD, Kocsis JH, Labar DR Department of Neurology and Neuroscience, Weill
Medical College of Cornell University, New York, New York 10021, USA.
PURPOSE: Antiepileptic drugs (AEDs) are frequently used
for their beneficial psychoactive effects on affective disorders. We sought to demonstrate
a psychoactive effect of gabapentin (GBP) when used as add-on AED therapy. METHODS: Forty
adult patients with partial epilepsy were studied in a prospective, non-randomized fashion
with interviewer-rated and self-rated scales of mood and anxiety: the Cornell Dysthymia
Rating Scale (CDRS), Beck Depression Inventory (BDI), and Hamilton Depression (Ham-D) and
Anxiety (Ham-A) Scales. After completion of baseline mood and anxiety scales (time 1), 20
of the 40 patients were prescribed add-on GBP (treated group). The remaining 20 patients
served as a control group. Both groups were similar in age and sex distribution. Follow-up
mood and anxiety scales were performed in all patients approximately 3 months later (time
2). The average GBP dose at time 2 was 1,615 mg/day. All patients were taking stable doses
of one to four AEDs at baseline and throughout the study. Seizure frequency was monitored
throughout. Statistical significance was assessed by analysis of variance (ANOVA) by using
a two-factor repeated-measures model. RESULTS: The GBP-treated group had a significant
decrease in CDRS score over time compared with the control group (p = 0.04). No
significant differences between the control and the treated groups were found for any of
the remaining mood scales (BDI, p = 0.58; Ham-D, p = 0.59; Ham-A, p = 0.93). There was no
significant difference or change in seizure frequency between groups. CONCLUSIONS: GBP
treatment is associated with mood improvement as measured by the CDRS. This improvement
was not accounted for by seizure improvement. PMID: 10448827, UI: 99376057
Drugs Exp Clin Res 1999;25(4):185-91
Low dose gabapentin for shoulder-hand syndrome induced
by phenobarbital: a three-month study.
Rovetta G, Baratto L, Monteforte P Faculty of
Rheumatology, University of Genoa, Rheumatological Center, Bruzzone Institute USL 3,
Italy.
Both the pathogenetic interpretation and treatment of
phenobarbital-induced rheumatism are uncertain. The reflex sympathetic dystrophy syndrome
which complicates antiepileptic drug therapy is a problem for rheumatologists. The aim of
our study was to test the effect of gabapentin as an additional therapy in patients
suffering from phenobarbital-induced shoulder-hand syndrome when these patients were
treated with gabapentin instead of receiving phenobarbital only. After a 3-month
observation period, the pain and the movement range from the shoulder to the wrist and to
the hand improved more than in the control group using acetaminophen. Further studies are
required to confirm this observation. PMID: 10442276, UI: 99370864
Ann Clin Psychiatry 1999 Jun;11(2):61-6
The use of primidone in the treatment of refractory
bipolar disorder.
Schaffer LC, Schaffer CB, Caretto J Sutter Community
Hospitals, Sacramento, California, USA.
Four anticonvulsant medications (carbamazepine,
valproate, gabapentin and lamotrigine) have received attention in the psychiatric
literature as efficacious treatment for bipolar disorder, either as monotherapy or as
adjunctive agents. Although two earlier reports in 1993 suggested that primidone may also
be helpful for bipolar disorder, this older anticonvulsant has not been evaluated in any
subsequent studies to confirm these earlier findings. In the present prospective open
study, 26 patients with refractory bipolar disorder were treated with primidone as an
adjunctive therapy. Eight (31%) patients experienced a persistent positive therapeutic
effect. Five (19%) patients were considered partial or temporary responders to primidone.
The remaining 13 patients (50%) were considered treatment failures. Although a 31%
response rate is considered modest in most psychotropic medication studies, the authors
believe that this success rate is significant in this refractory patient population and
should provide impetus for future more scientific studies to confirm the preliminary
findings of this open trial. PMID: 10440522, UI: 99367134
Anesth Analg 1999 Aug;89(2):434-9
The effect of intrathecal gabapentin on pain behavior
and hemodynamics on the formalin test in the rat.
Yoon MH, Yaksh TL Department of Anesthesiology,
University of California, San Diego 92093-0818, USA.
In this study, we examined the effect of intrathecal
(i.t.) gabapentin, administered before and after the injection of formalin into the rat
hindpaw, on pain behavior and hemodynamics. Formalin evoked a biphasic flinching behavior
and hypertension. I.t. gabapentin administered 10 min before formalin produced a
dose-dependent reduction of the Phase 2, but not Phase 1, flinching and cardiovascular
response. In contrast, i.t. gabapentin administered 9 min after formalin had no effect on
either phase of flinching. I.t. D-serine (100 micrograms) administered 10 min before i.t.
galapentin reversed the Phase 2 effect of gabapentin. I.t. gabapentin did not affect the
thermal escape latency or the baseline cardiovascular measures even at the largest dose
(300 micrograms). These results indicate that the spinal effect of gabapentin reduces the
somatosympathetic reflex and somatosensory response to tissue injury without an
accompanying effect on acute nociception or resting sympathetic outflow. Implications:
After tissue injury, there is an enhanced pain behavior and cardiovascular response,
representing a facilitated state of spinal processing. Spinally delivered gabapentin had
no evident effect on resting heart rate or blood pressure, but it attenuated the enhanced
pain behavior and cardiovascular response otherwise produced by injury. PMID: 10439761,
UI: 99368634
South Med J 1999 Jul;92(7):642-9
Treatment of chronic pain with antiepileptic drugs: a
new era.
Hansen HC Department of Anesthesia and Pain Medicine,
Davis Medical Center, Statesville, NC, USA.
BACKGROUND: Shortcomings of traditional pain relief
agents have led physicians to investigate other alternatives, such as antiepileptic drugs.
Safe, effective, nonhabituating agents are currently available to enhance pain treatment
strategies. METHODS: In this article, various pharmacologic options and their mechanisms
of action are reviewed briefly, with a focus on treatment of chronic pain with
antiepileptic drugs (AEDs). RESULTS: Antiepileptic drugs have been widely studied and
prescribed for the relief of acute and chronic pain. Similarities in the neurophysiology
of pain and epilepsy suggest that AEDs may be a suitable adjunct in the management of
chronic pain. Of the newer AEDs, gabapentin shows the greatest potential and appears to be
well tolerated by patients. CONCLUSIONS: Treatment of chronic pain remains a challenge for
physicians and patients. Further research is required to identify the role of various
agents and their effect on patient return to function and quality of life. Publication
Types: Review Review, tutorial PMID: 10414471, UI: 99341421
Arch Neurol 1999 Jul;56(7):807-8
A new twist for stopping the shakes? Revisiting
GABAergic therapy for essential tremor.
Louis ED Department of Neurology and the Gertrude H.
Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY,
USA.
Aside from physiological tremor, essential tremor (ET)
is by far the most common cause of tremor in humans, affecting large numbers of
individuals in every human population. The crude prevalence of ET has been conservatively
estimated to be between 0.4% and 3.9%, although some estimates of the prevalence of ET
among the elderly are higher than 20%. Essential tremor is the most prevalent adult-onset
movement disorder, and is also regarded as one of the most common neurological disorders
of adults, with a prevalence that is similar to or greater than that of stroke, Alzheimer
disease, migraine headache, and lumbosacral pain syndromes. Essential tremor is as much as
20 times more prevalent than Parkinson disease. Publication Types: Review Review, tutorial
PMID: 10404981, UI: 99331867
Eur Neurol 1999 Jul;42(1):49-51
Gabapentin as Treatment for Hemifacial Spasm.
Bandini F, Mazzella L Department of Neurological
Sciences and Neurorehabilitation, University of Genoa, Italy.
Hemifacial spasm, a life-long condition characterized by
involuntary unilateral contractions of the facial muscles, is a disabling disorder often
resulting in patient irritation and social embarassment. Its probable etiology is
neurovascular compression of the facial nerve at its root exit zone. The current medical
treatment consists of either baclofen or anticonvulsant drugs, with limitation due to side
effects or low efficacy. In recent years botulinum toxin injection and microvascular
decompression of the facial nerve have been shown to be highly successful. However, both
procedures share some complications and require special techniques. We present 5 patients
affected by hemifacial spasm who responded well to the novel anticonvulsant drug
gabapentin. Gabapentin was administered at a dose ranging from 900 to 1,600 mg daily, with
rapid and clear improvement of spasms and absence of any remarkable adverse effects. Our
findings suggest that gabapentin may be an effective treatment for patients with
hemifacial spasm with a very good ratio of therapeutic effects to side effects when
compared with other drugs currently used. PMID: 10394048
J Pain Symptom Manage 1999
Jun;17(6):441-5
Gabapentin as an adjuvant to opioid analgesia for
neuropathic cancer pain.
Caraceni A, Zecca E, Martini C, De Conno F Pain Therapy
and Palliative Care Division, National Cancer Institute of Milan, Italy.
Gabapentin was administered as an "add on"
therapy to 22 patients with neuropathic cancer pain only partially responsive to opioid
therapy. Global pain, burning pain, shooting pain episodes, and allodynia were assessed
separately. Gabapentin was given for at least a week and efficacy was assessed after 7 to
14 days of therapy. Global pain score decreased from a mean (+/- SD) of 6.4 (+/- 1.5) to
3.2 (+/- 1.3) (95% confidence interval of the baseline minus final score differences [95%
CI] = 1.0-2.4). Burning pain intensity decreased from a mean (+/- SD) of 5.1 (+/- 3.6) to
2.0 (+/- 2.3) (95% CI = 1.5-3.8), and episodes of shooting pain decreased in frequency
from 7.2 (+/- 3.7) to 2.2 (+/- 2.2) daily episodes (95% CI = 1.8-4.3). Allodynia was found
in 9 patients and disappeared in 7 during gabapentin administration. Twenty patients
judged the new drug efficacious in relieving their symptoms. The potential role of
gabapentin as an adjuvant to opioid analgesia in cancer pain is discussed. Publication
Types: Clinical trial PMID: 10388250, UI: 99314305
Curr Opin Ophthalmol 1998
Oct;9(5):32-8
Nystagmus.
Gottlob I Department of Strabismus and
Neuro-Ophthalmology, Kantonsspital St. Gallen, Switzerland.
This article reviews some of the past year's important
papers, with emphasis on early onset and acquired neurological nystagmus. Advances in
understanding the mechanisms of suppression of oscillopsia, the evolution of nystagmus,
and the treatment of periodic alternating nystagmus and of nystagmus in albinism have been
made in early-onset nystagmus. Successful pharmacological treatment for acquired
neurological nystagmus has been demonstrated with the gamma aminobutyric acid agonist
gabapentin and with memantine, a glutamate antagonist. Publication Types: Review Review,
tutorial PMID: 10387479, UI: 99260054
Epilepsia 1999 May;40(5):590-600
New antiepileptic drugs: comparison of key clinical
trials.
Cramer JA, Fisher R, Ben-Menachem E, French J, Mattson
RH Yale University School of Medicine, New Haven, Connecticut, USA. Joyce.Cramer@Yale.edu
PURPOSE: Data accrued from clinical trials of five new
antiepileptic drugs (AEDs) are compared for efficacy in reducing seizures and
self-reported adverse events as a basis of selection among new AEDs. Drawbacks to use of
these data also are demonstrated. METHODS: A review of double-blind, placebo-controlled
clinical trials of a new AED or placebo added to a standard AED provided data on reduction
of complex partial seizures (CPSs). Success is > or =50% fewer CPSs with a new AED or
placebo; Overall Improvement is the success rate with drug minus the success rate with
placebo. Adverse events were tabulated from product-labeling lists of COSTART items
(incidence, > or =5%). The Summary Complaint score is the total number of reports of
individual events for each AED. RESULTS: Efficacy data demonstrate differences in Overall
Improvement rates among five new AEDs and placebos (p = 0.001). However, rates of response
to placebo also differed significantly among trials (p = 0.01). Adverse events
predominantly affect central nervous system, psychiatric, and general body systems.
However, patients in the placebo control groups did not consistently report adverse
effects. Summary Complaint scores differ among the five new AEDs, but variability in use
of COSTART terms nullifies comparisons. CONCLUSIONS: Comparisons of data for five new AEDs
provide information for selection among treatments when a second drug is needed to improve
control of CPSs. However, significant differences among the control groups and other
problems make comparisons between trials problematic. The final choice should be based on
the need of the individual patient for superior seizure control versus minimal adverse
effects. Publication Types: Review Review, tutorial PMID: 10386528, UI: 99313099
J Pharmacol Exp Ther 1999
Jul;290(1):214-9
Gabapentin attenuates nociceptive behaviors in an acute
arthritis model in rats.
Lu Y, Westlund KN Department of Anatomy and Neuroscience
and The Marine Biomedical Institute, The University of Texas Medical Branch at Galveston,
Galveston, Texas, USA.
In this study, we investigated the effectiveness of
gabapentin (Neurontin), administered spinally with a microdialysis fiber, in reducing
nociceptive behavioral responses induced by a knee joint inflammation model. This model is
produced by injection of the knee joint with kaolin and carrageenan in rats. The resultant
knee joint inflammation produces a secondary hyperalgesia to radiant heat applied to the
hindpaw. Both pretreatment and post-treatment protocols were examined. Spinal
administration of gabapentin (10 mg/ml) infused 1.5 h before induction of knee joint
inflammation, although having no effect on the baseline, prevented the development of heat
hyperalgesia. Gabapentin also prevented the development of other pain-related behaviors
scored subjectively. Gabapentin had no effect, however, on the joint circumference
increase typical in this model. In animals with fully developed knee joint inflammation,
gabapentin produced a reversal of heat hyperalgesia. The paw withdrawal latency responses
and subjective pain scores were no longer significantly different from baseline, but joint
circumference increases remained. These data suggest that gabapentin is an effective
antinociceptive agent when administered either before or after induction of knee joint
inflammation acting through a central neurogenic mechanism. PMID: 10381778, UI: 99310843
Cell Mol Neurobiol 1999
Aug;19(4):511-32
Metabolism and excretion of mood stabilizers and new
anticonvulsants.
Ketter TA, Frye MA, Cora-Locatelli G, Kimbrell TA, Post
RM Department of Psychiatry and Behavioral Sciences, Stanford University School of
Medicine, California 94305-5723, USA.
1. The mood stabilizers lithium, carbamazepine (CBZ),
and valproate (VPA), have differing pharmacokinetics, structures, mechanisms of action,
efficacy spectra, and adverse effects. Lithium has a low therapeutic index and is renally
excreted and hence has renally-mediated but not hepatically-mediated drug-drug
interactions. 2. CBZ has multiple problematic drug-drug interactions due to its low
therapeutic index, metabolism primarily by a single isoform (CYP3A3/4), active epoxide
metabolite, susceptibility to CYP3A3/4 or epoxide hydrolase inhibitors, and ability to
induce drug metabolism (via both cytochrome P450 oxidation and conjugation). In contrast,
VPA has less prominent neurotoxicity and three principal metabolic pathways, rendering it
less susceptible to toxicity due to inhibition of its metabolism. However, VPA can
increase plasma concentrations of some drugs by inhibiting metabolism and increase free
fractions of certain medications by displacing them from plasma proteins. 3. Older
anticonvulsants such as phenobarbital and phenytoin induce hepatic metabolism, may produce
toxicity due to inhibition of their metabolism, and have not gained general acceptance in
the treatment of primary psychiatric disorders. 4. The newer anticonvulsants felbamate,
lamotrigine, topiramate, and tiagabine have different hepatically-mediated drug-drug
interactions, while the renally excreted gabapentin lacks hepatic drug-drug interactions
but may have reduced bioavailability at higher doses. 5. Investigational anticonvulsants
such as oxcarbazepine, vigabatrin, and zonisamide appear to have improved pharmacokinetic
profiles compared to older agents. 6. Thus, several of the newer anticonvulsants lack the
problematic drug-drug interactions seen with older agents, and some may even (based on
their mechanisms of action and preliminary preclinical and clinical data) ultimately prove
to have novel psychotropic effects. PMID: 10379423, UI: 99308231
Epilepsy Res 1999 Jun;35(2):109-21
Cognitive abilities and adjustment with gabapentin:
results of a multisite study.
Dodrill CB, Arnett JL, Hayes AG, Garofalo EA, Greeley
CA, Greiner MJ, Pierce MW Regional Epilepsy Center, Harborview Medical Center, Seattle, WA
98104-2499, USA. cdodrill@u.washington.edu
The cognitive and quality of life effects of gabapentin
are not yet well explored. While preliminary work in the area has provided positive
findings, a large double-blinded study has been needed to explore this area more
thoroughly. From 24 sites in North America, 201 adults were studied who had uncontrolled
complex partial seizures with or without secondary generalization. Attempts were made to
convert each patient from one or two marketed antiepileptic drugs (AEDs) taken in baseline
to gabapentin monotherapy (600, 1200, or 2400 mg/day). Tests of cognitive abilities and
adjustment were administered at the end of the 8-week baseline period and at the end of
the 26-week double-blind treatment period. Analyses of baseline to treatment period
changes were conducted for each dose group in comparison with a reference group of
placebo-treated patients from another study. In the area of cognitive functioning, no
changes in any of the gabapentin groups were found in comparison with the reference group.
In the area of adjustment and mood, however, improvement with gabapentin administration
was noted on several variables pertaining to emotional and interpersonal adjustment. These
results are consistent with findings from previous studies. PMID: 10372564, UI: 99299779
Pediatr Neurol 1999 May;20(5):381-2
Gabapentin for self-injurious behavior in Lesch-Nyhan
syndrome.
McManaman J, Tam DA Department of Pediatrics and
Clinical Investigations, Naval Medical Center San Diego, California 92134-1005, USA.
Self-injurious behavior is a common clinical problem in
children with Lesch-Nyhan syndrome, an X-linked disorder of purine metabolism. This
behavior is not observed in other conditions associated with increased serum
concentrations of uric acid, hypoxanthine, and xanthine. Various neurotransmitters appear
to play a pivotal role in self-injurious behavior. The authors present a patient with
Lesch-Nyhan syndrome, whose self-injurious behavior was effectively treated with
gabapentin, and discuss possible mechanisms of action. PMID: 10371385, UI: 99297795
Eur J Neurol 1999 Jul;6(4):505-507
A patient with multiple sclerosis and Down's syndrome
with a rare paroxysmal symptom at onset.
Solaro C, Uccelli MM, Mancardi GL Department of
Neurological Sciences and Rehabilitation, University of Genoa, Italy.
Down's syndrome (DS) is often associated with autoimmune
diseases, although an association with multiple sclerosis (MS) has not been previously
reported. A 49-year-old male with DS experienced progressively worsening gait and bladder
dysfunction. Following Poser criteria, the patient was diagnosed with laboratory-supported
definite MS. Ten days following diagnosis the patient experienced dysestetic paroxysmal
pain at the pelvic level (an uncommon complaint in MS) which was initially addressed with
carbamazepine, resulting in mild relief and adverse effects consisting of increased motor
deficit and decreased daytime alertness. A titration combination of lamotrigine and
gabapentin, two relatively new antiepileptic drugs which have been utilized individually
for a number of neurological symptoms, resulted in significant reduction in pain frequency
and intensity, with no adverse effects. This case study presents details of the first
reported association of DS and MS, between which the pathogenetic relationship remains
unclear. The presence of a rare symptom complaint in MS, as well as the effective
combination of lamotrigine and gabapentin for treating this symptom, without adverse
effects is an additional interesting aspect of this case. Copyright 1999 Lippincott
Williams & Wilkins PMID: 10362908
Neuropharmacology 1999
May;38(5):611-23
Selective NMDA NR2B antagonists induce antinociception
without motor dysfunction: correlation with restricted localisation of NR2B subunit in
dorsal horn.
Boyce S, Wyatt A, Webb JK, O'Donnell R, Mason G, Rigby
M, Sirinathsinghji D, Hill RG, Rupniak NM Merck Sharp Laboratory, Neuroscience Research
Centre, Harlow, UK. susan_boyce@merck.com
The present study investigated the regional distribution
of the N-methyl-D-aspartate (NMDA) receptor containing the NR2B subunit protein in rat
lumbar spinal cord and examined whether selective NR2B antagonists would exhibit
antinociception with reduced side-effect liability than subtype non-selective NMDA
antagonists and anticonvulsants. Immunocytochemical studies showed the NR2B subunit had a
restricted distribution, with moderate labelling of fibres in laminas I and II of the
dorsal horn suggesting a presynaptic location on primary afferent fibers and possible
involvement in pain transmission. In the in vivo studies, the NMDA/glycine antagonists
(MK-801, 0.02-1 mg/kg i.p., L-687,414 10-300 mg/kg i.p., and L-701,324 1-10 mg/kg i.p.)
and the anticonvulsant, gabapentin (10-500 mg/kg p.o.), induced rotarod deficits at
antinociceptive doses. In contrast, the selective NR2B antagonists, (+/-)-CP-101,606
(1-100 mg/kg p.o.) and (+/-)-Ro 25-6981 (3-100 mg/kg i.p.) showed a significant dose
window. (+/-)-CP-101,606 caused no motor impairment or stimulation in rats at doses up to
100 mg/kg p.o., which is far in excess of those inhibiting allodynia in neuropathic rats
(ID50 4.1 mg/kg, p.o.). (+/-)-Ro 25-6981 also showed a significant separation (ID50
allodynia 3.8 mg/kg, i.p.), however, some disruption of rotarod performance was observed
at 100 mg/kg. The anticonvulsant lamotrigine (3-500 mg/kg p.o.) also showed a good dose
window. These findings demonstrate that NR2B antagonists may have clinical utility for the
treatment of neuropathic and other pain conditions in man with a reduced side-effect
profile than existing NMDA antagonists. PMID: 10340299, UI: 99271658
Pharmacotherapy 1999
May;19(5):565-72
Gabapentin: a review of published experience in the
treatment of bipolar disorder and other psychiatric conditions.
Letterman L, Markowitz JS Department of Pharmacy
Practice, Medical University of South Carolina, Charleston 29425, USA.
Successful therapy with valproate and carbamazepine in
patients with psychiatric disorders led to investigation of other anticonvulsants for
similar indications. Gabapentin is a relatively new anticonvulsant being investigated for
potential use in the treatment of bipolar disorder (BD), anxiety disorders, behavioral
dyscontrol, and substance use disorders. Its favorable side effect profile, absence of the
need for therapeutic drug monitoring, and minimal drug interactions give gabapentin a
potential role in these indications. Computer searches of the biomedical literature were
undertaken to identify all pertinent case reports, case series, and studies of the drug as
monotherapy or adjunctive therapy for BD; 10 reports were retrieved. In the treatment of
various anxiety disorders, one study, one case report, and one case series were
identified. At least one case series described gabapentin therapy for alcohol withdrawal
and one case report of the drug for agitation associated with dementia. Published,
well-designed studies evaluating the agent's effectiveness as monotherapy for BD are
lacking. Its benefit as an adjunctive treatment with other mood stabilizers is also
unestablished. Data regarding its efficacy in the treatment of anxiety disorders or
manifestations of substance abuse are limited. These areas may deserve further
investigation. Publication Types: Review Review, tutorial PMID: 10331819, UI: 99260662
Br J Pharmacol 1999
Apr;126(7):1634-8
Effects of anti-epileptic drugs on glutamine synthetase
activity in mouse brain.
Fraser CM, Sills GJ, Forrest G, Thompson GG, Brodie MJ
University Department of Medicine and Therapeutics, Western Infirmary, Glasgow.
1. Glutamine synthetase (GS) is a key enzyme in the
regulation of glutamate neurotransmission in the central nervous system. It is responsible
for the conversion of glutamate to glutamine, and for the detoxification of ammonia. 2. We
have investigated the effects of single and repeated intraperitoneal administration of a
range of established and new anti-epileptic drugs on GS activity in mouse brain. 3. Four
hours after the final dose, animals were sacrificed and the brains removed for analysis of
GS activity. 4. Both single and repeated doses of phenytoin and carbamazepine were found
to reduce enzyme activity (P<0.05). 5. Single doses of phenobarbitone, felbamate and
topiramate were without effect, however repeated administration of these drugs
dose-dependently reduced GS activity (P<0.05). 6. Single and repeated doses of sodium
valproate, vigabatrin, lamotrigine, gabapentin, tiagabine, levetiracetam and
desglycinyl-remacemide were found to have no effect on GS activity. 7. The reduction in
enzyme activity demonstrated is unlikely to be related to the anti-epileptic actions of
these drugs, but may contribute to their toxicity. PMID: 10323596, UI: 99255196
Epilepsy Res 1999 May;35(1):13-20
Gabapentin modifies extracellular opioid peptide content
in amygdala: a microdialysis study.
Rocha L, Ondarza-Rovira R, Maidment NT Instituto
Mexicano de Psiquiatria, Division de Neurociencias, Mexico, D.F. rocha@cenids.ssa.gob.mx
Opioid peptide release was monitored in the amygdala and
hippocampus of freely moving rats following a single oral administration of gabapentin
using microdialysis. Extracellular opioid peptide levels were elevated above basal levels
in the amygdala within the first 60 (54%) and 90 min (68%) after gabapentin
administration. Levels returned to basal conditions 120 min following the treatment. No
significant changes were detected in the hippocampus. The majority of immunoreactive
material recovered from the amygdala following gabapentin administration was identified as
Leu-enkephalin and Met-enkephalin by high performance liquid chromatography (HPLC)
analysis. It is proposed that the enhanced opioid peptide release in the amygdala induced
by gabapentin might be involved with the antiepileptic effects as well as with some
adverse events produced by this drug. PMID: 10232790, UI: 99247775
Pharm Res 1999 Apr;16(4):519-26
Transport of pregabalin in rat intestine and Caco-2
monolayers.
Jezyk N, Li C, Stewart BH, Wu X, Bockbrader HN, Fleisher
D College of Pharmacy, The University of Michigan, Ann Arbor 48109-1065, USA.
PURPOSE: The purpose of this study was to determine if
the intestinal transport of pregabalin (isobutyl gamma-aminobutyric acid, isobutyl GABA),
a new anticonvulsant drug, was mediated by amino acid carriers with affinity for large
neutral amino acids (LNAA). METHODS: Pregabalin transport was studied in rat intestine and
Caco-2 monolayers. An in vitro Ussing/diffusion chamber model and an in situ single-pass
perfusion model were used to study rat intestinal transport. An in vitro diffusion chamber
model was used to evaluate Caco-2 transport. RESULTS: In rat ileum, pregabalin transport
was saturable and inhibited by substrates of intestinal LNAA carriers including neurontin
(gabapentin), phenylalanine, and proline. Weak substrates of intestinal LNAA carriers
(beta-alanine, gamma-aminobutyric acid, and methyl aminoisobutyric acid) did not
significantly change pregabalin transport. In Caco-2 monolayers that showed a high
capacity for phenylalanine transport, pregabalin transport was concentration- and
direction-independent and equivalent in magnitude to the paracellular marker, mannitol.
The in vitro and in situ rat ileal permeabilities of the LNAA carrier-mediated compounds
neurontin, pregabalin, and phenylalanine correlated well with the corresponding in vivo
human oral absorption. CONCLUSIONS: The transport of pregabalin was mediated by LNAA
carriers in rat ileum but not in Caco-2 monolayers. Caco-2 was not an appropriate model
for evaluating the in vivo human oral absorption of pregabalin and neurontin. PMID:
10227706, UI: 99242265
Eur J Pharmacol 1999 Mar
26;369(3):335-8
Gabapentin decreases the severity of dystonia at low
doses in a genetic animal model of paroxysmal dystonic choreoathetosis.
Richter A, Loscher W Department of Pharmacology,
Toxicology and Pharmacy, School of Veterinary Medicine, Hannover, Germany.
arichter@pharma.tiho-hannover.de
The effects of the gamma-aminobutyric acid
(GABA)-potentiating drug gabapentin (1-(aminomethyl) cyclohexaneacetic acid) on severity
of dystonia were examined in a hamster model of idiopathic paroxysmal dystonic
choreoathetosis. In the genetically dystonic hamster (dt(sz)) recent pharmacological and
neurochemical studies suggested that disturbed GABAergic inhibition is involved in the
pathogenesis. In line with a case report of beneficial effects in human paroxysmal
dystonic choreoathetosis, gabapentin reduced the severity of dystonia in mutant hamsters
at doses of 5 and 10 mg kg(-1) i.p. At higher doses (20 and 100 mg kg(-1)), gabapentin,
however, failed to exert antidystonic effects. The GABApotentiating activity of gabapentin
could explain the antidystonic effects of low doses, while the loss of efficacy at higher
doses may be due to other mechanisms of gabapentin. PMID: 10225372, UI: 99239878
J Clin Psychiatry 1999
Apr;60(4):245-8
Clinical experience with gabapentin in patients with
bipolar or schizoaffective disorder: results of an open-label study.
Cabras PL, Hardoy MJ, Hardoy MC, Carta MG Department of
Neurological and Psychiatric Sciences, University of Florence, Italy.
BACKGROUND: This study was carried out to evaluate the
efficacy, tolerability, and safety of gabapentin as an adjunctive treatment in patients
with bipolar or schizoaffective disorder with manic or hypomanic symptoms. METHOD:
Twenty-five patients fulfilling DSM-IV diagnostic criteria for bipolar I disorder or
schizoaffective disorder underwent a 16-week, open-trial treatment with gabapentin.
Symptom severity was measured using the Clinical Global Impressions scale (CGI) and the
Brief Psychiatric Rating Scale (BPRS). Baseline scores and final scores were compared by
using the Student t test and the Friedman range variance analysis. RESULTS: Twenty-two
patients (88%) completed the 16 weeks of treatment with gabapentin; 19 (76%) had a
positive response as measured by changes in CGI and BPRS scores. The mean dose was 1440
mg/day. The only side effect observed was oversedation, which decreased with continuing
treatment. CONCLUSION: Gabapentin was effective in the treatment of mania and hypomania in
patients with bipolar and schizoaffective disorders. If confirmed in controlled studies,
these findings suggest that gabapentin represents a well-tolerated, rapidly acting
antimanic agent. Publication Types: Clinical trial PMID: 10221286, UI: 99236475
Pediatr Neurol 1999 Mar;20(3):195-7
Development of two stable oral suspensions for
gabapentin.
Nahata MC College of Pharmacy, Ohio State University,
Columbus 43210, USA.
Gabapentin is not available in a liquid dosage form for
clinical use. This study was designed to develop two oral gabapentin suspensions and
determine their stability under refrigeration or at room temperature. Commercially
available gabapentin capsules were used to prepare two suspensions: one in
extemporaneously prepared 1% methylcellulose in syrup (1:1) and another in equal volumes
of commercially available suspending agents/syrup (Ora Plus/Ora Sweet). Each suspension
containing gabapentin (100 mg/mL) was stored in 10 plastic prescription bottles; five were
stored at 4 degrees C and five at 25 degrees C. Three 500-microL samples were collected
immediately after preparation (day 0) and on days 7, 14, 28, 42, 56, 70, and 91.
Gabapentin was measured by accurate, reproducible, specific, and stability-indicating
high-performance liquid chromatography (n = 15). The observed mean concentrations exceeded
90% of the initial concentrations in both suspensions for 91 days at 4 degrees C and 56
days at 25 degrees C. No change in pH, odor, or physical appearance was observed. On the
basis of these results, stable oral suspensions of gabapentin can be prepared and stored
in plastic prescription bottles for 91 days at 4 degrees C or 56 days at 25 degrees C.
PMID: 10207927, UI: 99224334
Arch Neurol 1999 Apr;56(4):475-80
A randomized placebo-controlled comparative trial of
gabapentin and propranolol in essential tremor.
Gironell A, Kulisevsky J, Barbanoj M, Lopez-Villegas D,
Hernandez G, Pascual-Sedano B Department of Neurology, Sant Pau Hospital, Autonomous
University of Barcelona, Spain.
BACKGROUND: New medication is needed to treat essential
tremor. Preliminary evidence suggests that gabapentin may be effective in the treatment of
this disorder. OBJECTIVE: To study the effects of gabapentin in a comparative,
double-blind, crossover, placebo-controlled trial of patients who have essential tremor.
PATIENTS AND METHODS: 16 patients with essential tremor (6 with a new onset and 10 with a
2-week washout period of previous treatment with propranolol hydrochloride) received
gabapentin (Neurontin), 400 mg 3 times daily; propranolol hydrochloride, 40 mg 3 times
daily; and placebo for 15 days with a 1-week washout period between treatments. MAJOR
OUTCOME MEASURES: Major outcome evaluations consisted of a Tremor Clinical Rating Scale,
accelerometric recordings, and a self-reported disability scale obtained before drug
intake on study days 1 and 15 of each treatment period. In addition, the initial (day 1)
and superimposed (day 15) drug effects were studied before and 2, 4, 6, and 8 hours after
drug intake. RESULTS: At day 15, both gabapentin and propranolol demonstrated significant
and comparable efficacy in reducing tremor from baseline in all tremor measures. The
initial drug effects evaluated through accelerometry revealed no significant changes with
the use of a placebo, but gabapentin and propranolol use significantly reduced tremor
power. CONCLUSION: Gabapentin may be useful for the treatment of essential tremor.
Publication Types: Clinical trial Randomized controlled trial PMID: 10199338, UI: 99213430
Med Res Rev 1999 Mar;19(2):149-77
3-substituted GABA analogs with central nervous system
activity: a review.
Bryans JS, Wustrow DJ Parke-Davis Neuroscience Research
Center, Forvie Site, Cambridge, UK.
Gabapentin and Pregabalin are both 3-alkylated
gamma-amino butyric acid (GABA) analogs. Gabapentin was designed as a lipophilic GABA
analog and was first synthesized as a potential anticonvulsant and was launched in 1994 as
add-on therapy for the treatment of epilepsy. In this review the discovery and development
of gabapentin as an anticonvulsant are discussed. During human trials and while in
clinical use, it became apparent that gabapentin induced some other potentially useful
therapeutic effects in chronic pain states and behavioral disorders. A review of animal
and clinical data relating to these other potential therapeutic utilities is presented.
Pregabalin was identified after an investigation into other 3-substituted GABA analogs. It
has since been shown to have a similar pharmacological profile to gabapentin with greater
potency in preclinical models of pain and epilepsy. Studies of the mechanism(s) of action
of these compounds are discussed. Work towards identifying new analogs of both gabapentin
and pregabalin is also reviewed. Publication Types: Review Review, tutorial PMID:
10189176, UI: 99203059
Curr Opin Neurol 1999 Feb;12(1):21-7
Neuropharmacologic aspects of the ocular motor system
and the treatment of abnormal eye movements.
Leigh RJ, Ramat S Department of Neurology, Veterans
Affairs Medical Center, Cleveland, Ohio, USA. rjl4@po.cwru.edu
Neuropharmacology is aiding our understanding of the
control of eye movements in at least three ways. First, neurotransmitters have been
identified in the pathways that coordinate gaze. Second, the technique of pharmacologic
inactivation has provided a powerful method to determine the contributions of populations
of neurons to specific behaviors, such as steady gaze holding. Finally, the results of
basic neuropharmacologic studies have been used to identify candidate drugs for
therapeutic trials of abnormal eye movements. Publication Types: Review Review, tutorial
PMID: 10097880, UI: 99197953
Epilepsia 1999 Apr;40(4):474-9
Effects of age and gender on single-dose
pharmacokinetics of gabapentin.
Boyd RA, Turck D, Abel RB, Sedman AJ, Bockbrader HN
Department of Pharmacokinetics, Parke-Davis Pharmaceutical Research, Division of
Warner-Lambert Company, Ann Arbor, Michigan, USA.
PURPOSE: This study was conducted to evaluate the effect
of age, age-related changes in renal function, and gender on the single-dose
pharmacokinetics of orally administered gabapentin (GBP). METHODS: The pharmacokinetics of
a single 400-mg oral dose of GBP were studied in 36 healthy subjects (18 men and 18 women)
aged 20-78 years. Serial blood samples and total urine output were collected for 48 h
after the dose. GBP concentrations in plasma and urine were measured by high-performance
liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental
methods. RESULTS: All subjects tolerated the drug well, with only mild symptoms reported.
No change in maximal GBP plasma concentration (Cmax), time at which Cmax occurred (tmax),
or apparent volume of distribution (V/F) with age was noted. A significant linear decline
in apparent oral clearance (CL/F), elimination-rate constant (lambda z), and renal
clearance (CLR) with increasing age was observed (p < 0.005). Because total urinary
recovery of unchanged drug (an estimate of F for GBP) did not change with age, the decline
in CL/F and lambda z can be explained by the decline in CLR. The only pharmacokinetic
parameter that was significantly different between genders was Cmax, which was
approximately 25% higher for women than for men (p = 0.016), consistent with gender
differences in body size. CONCLUSIONS: The results of this study suggest that changes in
renal function are responsible for age-related changes in GBP pharmacokinetics. Reduction
of GBP dosage may be required in elderly patients with reduced renal function. The
pharmacokinetics of GBP are similar in men and women. PMID: 10219274, UI: 99236014
Acta Otorrinolaringol Esp 1999 Mar 1;50(2):175-177
[Use of gabapentin in glossopharyngeal neuralgia].
Garcia Callejo FJ, Marco Algarra J, Talamantes Escriba
F, Martinez Beneyto MP, Esparcia Navarro M, Morant Ventura A Servicio de ORL,Hospital
Clinico Universitario,Valencia,Valencia,Espana.
Anticonvulsant drugs, especially carbamazepine, are the
treatment of choice for glossopharyngeal neuralgia. If no clinical response is obtained,
surgical treatment, including nerve section or decompression, may be required. We report
the results obtained with a new anticonvulsant, gabapentin, as an alternative for cases of
carbamazepine failure. In 7 patients with bouts of glosso- pharyngeal neuralgia refractory
to the usual medical treatment, gabapentin produced improvement in 5 patients. Response
was poor in patients who had undergone surgical nerve decompression. Gabapentin was
concluded to be an effective therapeutic option for neuralgia of the IXth cranial nerve
before surgery. PMID: 10217696
Eur Neuropsychopharmacol 1999 Mar;9(3):257-8
Gabapentin as monotherapy in the treatment of acute
mania.
Hatzimanolis J, Lykouras L, Oulis P, Christodoulou GN
Department of Psychiatry, University of Athens, Eginition Hospital, Greece.
Two cases of mania treated with gabapentin, a new
anticonvulsant, are presented. After 2 weeks of treatment a moderate improvement of both
patients was observed. The antimanic effect of gabapentin awaits confirmation by
systematic, well designed studies. PMID: 10208297, UI: 99222978
Reg Anesth Pain Med 1999 Mar-Apr;24(2):170-4
Acute herpetic neuralgia and postherpetic neuralgia in
the head and neck: response to gabapentin in five cases.
Filadora VA 2nd, Sist TC, Lema MJ Department of
Anesthesiology and Pain Medicine, Roswell Cancer Institute, School of Medicine and
Biomedical Sciences, State University of New York at Buffalo, 14263, USA.
BACKGROUND AND OBJECTIVES: The clinical presentations
and pharmacologic management of three patients with acute herpetic neuralgia (AHN) and two
patients with postherpetic neuralgia (PHN), confined to the head and neck region, are
described. METHODS: Two patients had pain in the ophthalmic division of the trigeminal
nerve, two had pain confined to the C2-C4 dermatomes, and one patient had C2 pain with
radiating and referred pain to the second and third divisions of the trigeminal nerve.
RESULTS: Gabapentin, an anticonvulsant drug, was effective in treating these patients,
including the two cases of AHN. All patients reported complete pain relief after titration
with gabapentin up to 1,800 mg/d. The patients noted a dose-dependent decrease in pain
almost immediately after starting gabapentin. Specifically, reduction in the frequency and
intensity of allodynia, burning pain, shooting pain, and throbbing pain were noted. None
of the patients experienced side effects from the drug. CONCLUSIONS: In view of the
results in these patients, blinded, controlled studies are needed to determine the
efficacy of gabapentin for treating AHN and PHN. PMID: 10204905, UI: 99219599
Pain 1999 Mar;80(1-2):391-8
Gabapentin and pregabalin, but not morphine and
amitriptyline, block both static and dynamic components of mechanical allodynia induced by
streptozocin in the rat.
Field MJ, McCleary S, Hughes J, Singh L Department of
Biology, Parke-Davis Neuroscience Research Centre, Cambridge University Forvie Site, UK.
A single injection of streptozocin (50 mg/kg, i.p.) led
to the development of static and dynamic allodynia in the rat. The two responses were
detected, respectively, by application of pressure using von Frey hairs or lightly
stroking the hind paw with a cotton bud. Static allodynia was present in the majority of
the animals within 10 days following streptozocin. In contrast, dynamic allodynia took
almost twice as long to develop and was only present in approximately 60% of rats.
Morphine (1-3 mg/kg, s.c.) and amitriptyline (0.25-2.0 mg/kg, p.o.) dose-dependently
blocked static allodynia. However, neither of the compounds was effective against dynamic
allodynia. In contrast, gabapentin (10-100 mg/kg, p.o.) and the related compound
pregabalin (3-30 mg/kg, p.o.) dose-dependently blocked both types of allodynia. However,
the corresponding R-enantiomer (10-100 mg/kg, p.o.) of pregabalin, was found to be
inactive. The intrathecal administration of gabapentin dose-dependently (1-100
microg/animal) blocked both static and dynamic allodynia. In contrast, administration of
similar doses of gabapentin into the hind paw failed to block these responses. It is
suggested that in this model of neuropathic pain dynamic allodynia is mediated by A
beta-fibres and the static type involves small diameter nociceptive fibres. These data
suggest that gabapentin and pregabalin possess a superior antiallodynic profile than
morphine and amitriptyline, and may represent a novel class of therapeutic agents for the
treatment of neuropathic pain. PMID: 10204753, UI: 99219447
Neurosci Lett 1999 Mar 5;262(2):101-4
Gabapentin prevents hyperalgesia during the formalin
test in diabetic rats.
Cesena RM, Calcutt NA Department of Pathology,
University of California San Diego, La Jolla 92024-0612, USA.
The anticonvulsant agent gabapentin exhibits
antihyperalgesic properties in animal models of neuropathic pain. Diabetic rats display
increased nocifensive behavior during the formalin test of persistent chemical irritation
to the paw, suggesting the presence of abnormal pain processing mechanisms. We therefore,
investigated the efficacy of gabapentin on formalin-evoked behavior in diabetic rats.
Diabetic rats showed increased (P < 0.05) flinching during the normally quiescent phase
of the 5.0% formalin test. Gabapentin (50 mg/kg i.p. 30 min pre-test) suppressed flinching
during phases 1 and 2 of the formalin test in both control and diabetic rats but not the
increased flinching of diabetic rats during the quiescent phase. When 0.5% formalin was
used, diabetic rats exhibited increased flinching during both the quiescent phase and
phase 2. Gabapentin was without effect in controls but suppressed (P < 0.01) the
increased flinching in diabetic rats. Gabapentin displays efficacy against abnormal
sensory processing in diabetic rats and may be of benefit for treating painful diabetic
neuropathy. PMID: 10203241, UI: 99217904
Arch Neurol 1999 Apr;56(4):475-80
A randomized placebo-controlled comparative trial of
gabapentin and propranolol in essential tremor.
Gironell A, Kulisevsky J, Barbanoj M, Lopez-Villegas D,
Hernandez G, Pascual-Sedano B Department of Neurology, Sant Pau Hospital, Autonomous
University of Barcelona, Spain.
BACKGROUND: New medication is needed to treat essential
tremor. Preliminary evidence suggests that gabapentin may be effective in the treatment of
this disorder. OBJECTIVE: To study the effects of gabapentin in a comparative,
double-blind, crossover, placebo-controlled trial of patients who have essential tremor.
PATIENTS AND METHODS: 16 patients with essential tremor (6 with a new onset and 10 with a
2-week washout period of previous treatment with propranolol hydrochloride) received
gabapentin (Neurontin), 400 mg 3 times daily; propranolol hydrochloride, 40 mg 3 times
daily; and placebo for 15 days with a 1-week washout period between treatments. MAJOR
OUTCOME MEASURES: Major outcome evaluations consisted of a Tremor Clinical Rating Scale,
accelerometric recordings, and a self-reported disability scale obtained before drug
intake on study days 1 and 15 of each treatment period. In addition, the initial (day 1)
and superimposed (day 15) drug effects were studied before and 2, 4, 6, and 8 hours after
drug intake. RESULTS: At day 15, both gabapentin and propranolol demonstrated significant
and comparable efficacy in reducing tremor from baseline in all tremor measures. The
initial drug effects evaluated through accelerometry revealed no significant changes with
the use of a placebo, but gabapentin and propranolol use significantly reduced tremor
power. CONCLUSION: Gabapentin may be useful for the treatment of essential tremor.
Publication Types: Clinical trial Randomized controlled trial PMID: 10199338, UI: 99213430
Cleve Clin J Med 1999 Apr;66(4):239-45
Hypersensitivity syndrome to antiepileptic drugs: a
review including new anticonvulsants.
Hamer HM, Morris HH Department of Neurology, University
of Marburg, Germany.
Anticonvulsant hypersensitivity syndrome, a potentially
fatal but rare reaction, manifests as rash, fever, tender lymphadenopathy, hepatitis, and
eosinophilia. To manage hypersensitivity syndrome successfully, one must recognize the
symptoms early, stop the offending drug immediately, and substitute a safe, alternative
anticonvulsant medication. Hypersensitivity syndrome has not been described in patients
taking benzodiazepines or the newer anticonvulsants gabapentin or topiramate, and these
appear to be safe substitutes for drugs that cause the reaction. Publication Types: Review
Review, tutorial PMID: 10199060, UI: 99215273
Med Res Rev 1999 Mar;19(2):149-77
3-substituted GABA analogs with central nervous system
activity: a review.
Bryans JS, Wustrow DJ Parke-Davis Neuroscience Research
Center, Forvie Site, Cambridge, UK.
Gabapentin and Pregabalin are both 3-alkylated
gamma-amino butyric acid (GABA) analogs. Gabapentin was designed as a lipophilic GABA
analog and was first synthesized as a potential anticonvulsant and was launched in 1994 as
add-on therapy for the treatment of epilepsy. In this review the discovery and development
of gabapentin as an anticonvulsant are discussed. During human trials and while in
clinical use, it became apparent that gabapentin induced some other potentially useful
therapeutic effects in chronic pain states and behavioral disorders. A review of animal
and clinical data relating to these other potential therapeutic utilities is presented.
Pregabalin was identified after an investigation into other 3-substituted GABA analogs. It
has since been shown to have a similar pharmacological profile to gabapentin with greater
potency in preclinical models of pain and epilepsy. Studies of the mechanism(s) of action
of these compounds are discussed. Work towards identifying new analogs of both gabapentin
and pregabalin is also reviewed. PMID: 10189176, UI: 99203059
Br J Pharmacol 1999 Feb;126(3):689-96
An in vitro electrophysiological study on the effects of
phenytoin, lamotrigine and gabapentin on striatal neurons.
Calabresi P, Centonze D, Marfia GA, Pisani A, Bernardi G
Dip. Sanita, Universita di Roma Tor Vergata, Rome, Italy. calabre@uniroma2.it
We performed intracellular recordings from a rat
corticostriatal slice preparation in order to compare the electrophysiological effects of
the classical antiepileptic drug (AED) phenytoin (PHT) and the new AEDs lamotrigine (LTG)
and gabapentin (GBP) on striatal neurons. PHT, LTG and GBP affected neither the resting
membrane potential nor the input resistance/membrane conductance of the recorded cells. In
contrast, these agents depressed in a dose-dependent and reversible manner the
current-evoked repetitive firing discharge. These AEDs also reduced the amplitude of
glutamatergic excitatory postsynaptic potentials (EPSPs) evoked by cortical stimulation.
However, substantial pharmacological differences between these drugs were found. PHT was
the most effective and potent agent in reducing sustained repetitive firing of action
potentials, whereas LTG and GBP preferentially inhibited corticostriatal excitatory
transmission. Concentrations of LTG and GBP effective in reducing EPSPs, in fact, produced
only a slight inhibition of the firing activity of these cells. LTG, but not PHT and GBP,
depressed cortically-evoked EPSPs increasing paired-pulse facilitation (PPF) of synaptic
transmission, suggesting that a presynaptic site of action was implicated in the effect of
this drug. Accordingly, PHT and GBP, but not LTG reduced the membrane depolarizations
induced by exogenously-applied glutamate, suggesting that these drugs preferentially
reduce postsynaptic sensitivity to glutamate released from corticostriatal terminals.
These data indicate that in the striatum PHT, LTG and GBP decrease neuronal excitability
by modulating multiple sites of action. The preferential modulation of excitatory synaptic
transmission may represent the cellular substrate for the therapeutic effects of new AEDs
whose use may be potentially extended to the therapy of neurodegenerative diseases
involving the basal ganglia. PMID: 10188980, UI: 99202863
Epilepsy Res 1999 Feb;33(2-3):169-76
The reduction in paired-pulse inhibition in the rat
hippocampus by gabapentin is independent of GABA(B) receptor receptor activation.
Stringer JL, Lorenzo N Department of Pharmacology,
Baylor College of Medicine, Houston, TX 77030, USA. janets@bcm.tmc.edu
Previously we have shown that gabapentin causes a
reduction of paired-pulse inhibition in the dentate gyrus of the urethane-anesthetized
rat, which looks very much like the effect of baclofen on paired-pulse inhibition. In
addition, it has been proposed that gabapentin increases release of GABA from
non-vesicular stores and may, therefore, interact with GABA(B) mechanisms. Here we tested
the ability of a GABA(B) agonist, baclofen, and a GABA(B) antagonist, CGP35348, to block
the effect of gabapentin on paired-pulse inhibition in the dentate gyrus in
urethane-anesthetized adult Sprague-Dawley rats. Both baclofen (6 mg/kg) and gabapentin
(100 mg/kg) caused a long-lasting reduction of paired-pulse inhibition in the dentate
gyrus when given alone or in combination. CGP35348 (45 mg/kg) blocked the effect of
baclofen on paired-pulse inhibition, but did not alter the effect of gabapentin.
Gabapentin also caused a reduction of inhibition in the CA1 region, indicating that its
effect is not specific for the dentate gyrus. These results suggest that gabapentin
produces its effect on paired-pulse inhibition independent from the effect of baclofen and
not through non-vesicular release of GABA interacting with the GABA(B) receptor system.
PMID: 10094428, UI: 99192251
Fortschr Neurol Psychiatr 1999 Feb;67(2):75-80
[Predictors of response to phase prophylactics (mood
stabilizers) in bipolar affective disorders].
Walden J, Normann C, Langosch J, Grunze H
Universitatsklinik fur Psychiatrie und Psychosomatik, Abt. fur Psychiatrie und
Psychotherapie der Universitat Freiburg.
Since the introduction of lithium ions in the acute
treatment and in the prophylaxis of bipolar disorders the antiepileptic drugs valproate
and carbamazepine have been in use for several years as mood stabilizers. In a number of
open and controlled clinical studies predictors of response for the single drugs were
investigated. These studies indicated that valproate was a predictor of good response in
mixed (dysphoric) mania and bipolar rapid cycling. Moreover, valproate has a better
response than lithium in secondary mania (organic origin) and atypical mania (episode
sequence: depression-mania-euthymia rather than mania-depression-euthymia). The
preferential efficacy in the spectrum of bipolar disorders of the new antiepileptic drugs
lamotrigine and gabapentin must be analysed in more detail in future studies. Publication
Types: Review Review, tutorial PMID: 10093780, UI: 99193740
Postgrad Med 1999 Mar;105(3):59-61, 65-6, 73-4
How to help patients with restless legs syndrome.
Discerning the indescribable and relaxing the restless.
Evidente VG, Adler CH Parkinson's Disease and Movement
Disorders Center, Mayo Clinic Scottsdale, AZ 85259, USA.
Restless legs syndrome is a common, potentially
disabling condition that affects about 10% to 15% of the general population and yet is
often unrecognized and misdiagnosed. It is mainly diagnosed clinically and only rarely
requires polysomnography. The condition is usually primary and treatable. First, however,
secondary causes should be sought, especially iron deficiency and peripheral neuropathy,
because when the source is an accompanying factor or condition, the syndrome may be
curable. The most effective drugs are dopaminergic agents, clonazepam, opioids,
gabapentin, and clonidine. Additional agents are available that may be beneficial as
add-on or alternative therapy. Publication Types: Review Review literature PMID: 10086034,
UI: 99185953
J Am Pharm Assoc (Wash) 1999 Mar-Apr;39(2):217-21
Treatment of postherpetic neuralgia.
Menke JJ, Heins JR South Dakota State University,
Brookings 57007-0099, USA. menke.jennifer_@sioux-falls.va.gov
OBJECTIVE: To review treatment options for postherpetic
neuralgia (PHN). DATA SOURCES: Clinical literature selected by the authors accessed via
MEDLINE. Search terms included postherpetic neuralgia, capsaicin, antidepressants,
anticonvulsants, and lidocaine. STUDY SELECTION: Controlled trials relevant to PHN. DATA
SYNTHESIS: Traditional analgesics offer little benefit for the treatment of PHN. The best
results for pain relief have come from capsaicin and tricyclic antidepressants.
Anticonvulsants have also been used, although the number of studies evaluating this is
limited. More invasive therapies, such as transcutaneous electrical nerve stimulation and
nerve blocks, can be considered if other therapies fail. CONCLUSION: Early diagnosis and
treatment of herpes zoster may offer patients the best chance of preventing the
development of PHN. However, if PHN does develop, the patient should seek treatment early
for the best chance of pain relief. Publication Types: Review Review, tutorial PMID:
10079653, UI: 99179370
Ther Drug Monit 1999 Feb;21(1):137-8
Skin eruption with gabapentin in a patient with repeated
AED-induced Stevens-Johnson's syndrome.
DeToledo JC, Minagar A, Lowe MR, Ramsay RE Department of
Neurology, University of Miami, Florida 33136, USA.
Skin eruptions have been reported with the use of all
antiepileptic drugs and there is a significant risk of cross-reactivity between these
agents in causing serious eruptions such as Stevens-Johnson's syndrome. Gabepentin is
usually considered a safe agent for patients with a previous history of drug allergies and
there have been no cases of skin eruption reported to the gabapentin post marketing
surveillance. We report a patient who had severe Stevens-Johnson's syndrome induced by
phenytoin and later by carbamazepine. Subsequent use of gabapentin also resulted in a skin
eruption which was limited to the lower extremities but without systemic or mucosal
involvement. This case suggests that patients with a strong history of drug-induced
idiosyncratic reactions may experience such reactions to gabapentin as well. PMID:
10051068, UI: 99158355
Pharmacotherapy 1999 Feb;19(2):223-7
Increased risk of erythema multiforme major with
combination anticonvulsant and radiation therapies.
Micali G, Linthicum K, Han N, West DP Department of
Dermatology, University of Catania, Italy.
Erythema multiforme major (EMM; Stevens-Johnson
syndrome) is a cutaneous disorder associated with a wide variety of factors including
ingestion of drugs such as phenytoin and exposure to intracranial radiation therapy. Based
on observations of a 47-year-old black man with brain metastases who developed EMM after
combined phenytoin and radiation therapy, we conducted a MEDLINE literature search for
articles on similar cases from 1966 to the present. Twenty cases were identified that
support the hypothesis that EMM is associated with combined phenytoin and radiation
therapy. The reaction, or its severity, has no relationship to the phenytoin or radiation
therapy dosage, or to the histologic type of brain tumor. Also, EMM has no apparent age or
gender predisposition in association with phenytoin-radiation therapy. Thus this is a
clinical phenomenon that occurs with unusual frequency in patients with brain tumor who
undergo radiation therapy while taking phenytoin. Phenytoin and other anticonvulsants such
as phenobarbital and carbamazepine induce cytochrome P450 3A and produce oxidative
reactive intermediates that may be implicated in hypersensitivity reactions such as EMM.
Both carbamazepine and barbiturates have shown cross-sensitivity with phenytoin;
furthermore, a case of EMM in a patient receiving carbamazepine and whole brain radiation
therapy has been reported. As carbamazepine, valproate, and barbiturates have been
associated with EMM, gabapentin may be considered as alternative anticonvulsant therapy
when appropriate. Publication Types: Review Review of reported cases PMID: 10030773, UI:
99153844
J Pharmacol Exp Ther 1999 Mar;288(3):1026-30
Gabapentin suppresses ectopic nerve discharges and
reverses allodynia in neuropathic rats.
Pan HL, Eisenach JC, Chen SR Department of
Anesthesiology, Physiology, and Pharmacology, Wake Forest University School of Medicine,
Winston-Salem, North Carolina 27157-1009, USA. hpan@wfubmc.edu
Repetitive ectopic discharges from injured afferent
nerves play an important role in initiation and maintenance of neuropathic pain.
Gabapentin is effective for treatment of neuropathic pain but the sites and mechanisms of
its antinociceptive actions remain uncertain. In the present study, we tested a hypothesis
that therapeutic doses of gabapentin suppress ectopic afferent discharge activity
generated from injured peripheral nerves. Mechanical allodynia, induced by partial
ligation of the sciatic nerve in rats, was determined by application of von Frey filaments
to the hindpaw. Single-unit afferent nerve activity was recorded proximal to the ligated
sciatic nerve site. Intravenous gabapentin, in a range of 30 to 90 mg/kg, significantly
attenuated allodynia in nerve-injured rats. Furthermore, gabapentin, in the same
therapeutic dose range, dose-dependently inhibited the ectopic discharge activity of 15
injured sciatic afferent nerve fibers through an action on impulse generation. However,
the conduction velocity and responses of 12 normal afferent fibers to mechanical
stimulation were not affected by gabapentin. Therefore, this study provides
electrophysiological evidence that gabapentin is capable of suppressing the ectopic
discharge activity from injured peripheral nerves. This action may contribute, at least in
part, to the antiallodynic effect of gabapentin on neuropathic pain. PMID: 10027839, UI:
99152160
Clin Podiatr Med Surg 1999 Jan;16(1):67-79
Diagnostic algorithms for neuromuscular diseases.
Manon-Espaillat R, Mandel S Department of Neurology,
Jefferson Medical College, Philadelphia, Pennsylvania, USA.
Neuromuscular disorders can impose significant
disability in patients by virtue of weakness, pain, and sensory and autonomic symptoms and
deficits. For all of these disorders, supportive measures, appropriate physical therapy,
and respiratory support are beneficial. Pain management can be accomplished by the use of
antiepileptic medications, such as carbamazepine, phenytoin, valproic, and gabapentin.
Tricyclic antidepressants can also be helpful for pain management and depression.
Benzodiazepines and baclofen are helpful for management of spasticity. No specific
treatment exists yet for the motor neuron disorders. In peripheral neuropathies,
identifying and treating the cause is most important. In other neuropathies, such as in
acute or chronic inflammatory demyelinating neuropathies, immunosuppression is indicated.
Myasthenia gravis can be treated with cholinesterase inhibitors and immunosuppression. A
specific treatment does not exist yet for muscular dystrophies. Immunosuppression is
helpful in patients with inflammatory myopathies. Toxic myopathies can be treated by
removing the causative agent and by supportive measures. Endocrine myopathies will respond
to treatment of the primary endocrinopathy. Publication Types: Review Review, tutorial
PMID: 9929772, UI: 99128633
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