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Gabapentin
Selected AbstractsAN OPEN STUDY OF RILUZOLE VERSUS RILUZOLE PLUS GABAPENTIN IN AMYOTROPHIC LATERAL SCLEROSISJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2000V Palma A randomised open study has been carried out to evaluate the efficacy of riluzole versus riluzole plus gabapentin in 50 patients (23 males, 27 females) affected by amyotrophic lateral sclerosis (ALS), who received the diagnosis according to El Escorial WFN criteria. At baseline, the mean age of the patients was 58.8 ± 11.7 years and the mean disease duration was 11.4 ± 5.9 months. Twenty patients had bulbar and 30 spinal onset. Twenty-eight patients were randomly assigned to riluzole (100 mg/day) and 22 to riluzole plus gabapentin at the initial dose of 300 mg/day, slowly increased to 1800 mg/day. Informed consent was obtained in all cases. Before treatment, each patient underwent neurological examination, Appel rate scale, pulmonary function tests, electromyography, and transcranial magnetic stimulation. Clinical examination and electrophysiologic tests were repeated at three-month intervals. Over the course of the trial, 4 patients (8%) were lost to follow-up and 16 (32%, 9 in the riluzole and 7 in the riluzole plus gabapentin group) died. The mean age at death was 65.0 ± 6.5 years after a mean disease duration of 20.8 ± 7.9 months (range 13,36). There was no significant difference in response to treatment when severity and duration of the disease were compared in the two groups. [source] Critical review of oral drug treatments for diabetic neuropathic pain,clinical outcomes based on efficacy and safety data from placebo-controlled and direct comparative studiesDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 3 2005Hugo Adriaensen Abstract The present review aims to evaluate the efficacy and safety of a selection of oral treatments for the management of painful diabetic neuropathy. A literature review was conducted retrieving placebo-controlled and direct comparative studies with a selection of oral treatments for painful diabetic neuropathy. All studies were analyzed with regard to efficacy and tolerability. Efficacy was evaluated as the percentage improvement in pain intensity between baseline and endpoint. Tolerability was evaluated by means of study discontinuations due to adverse events and by incidence of drug-related adverse events. The analyzed trials enrolled different patient populations with mostly small numbers of patients. The great variability in dosages and dose titration schemes, cross-over designs with variable wash-out periods, and other design schemes made comparison between the different studies difficult. Gabapentin, lamotrigine, tramadol, oxycodone, mexiletine, and acetyl-L-carnitine were the only treatments studied in large (at least 100 patients), placebo-controlled parallel group trials. It is concluded that standardization in design and reporting for comparison of treatments is needed. Validated questionnaires for evaluation of the efficacy and safety should be further developed. Based on the reviewed randomised controlled trials, gabapentin shows good efficacy, a favourable side-effect profile with lack of drug interactions and therefore it may be a first choice treatment in painful diabetic neuropathy, especially in the elderly. However, head to head trials of current treatments are lacking and therefore randomized controlled trials are required to address this issue. Copyright © 2005 John Wiley & Sons, Ltd. [source] Treatment of symptomatic diabetic neuropathyDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue S1 2003Andrew J. M. Boulton Abstract Painful diabetic neuropathy is a common and particularly unpleasant long-term complication of diabetes that affects a significant minority of patients with distal polyneuropathy. After exclusion of other causes of neuropathic pain, attention should be focused on achieving optimal and stable glycaemic control avoiding flux of blood glucose levels, which have been shown to aggravate pain. Most patients will require pain control therapy and whilst the tricyclic drugs remain a first-line approach, their use is often hampered by predictable but troublesome side effects. Gabapentin, the only agent specifically licensed for the treatment of neuropathic pain in the United Kingdom, is useful in diabetic neuropathy and is generally better tolerated than the tricyclics. Additionally, other pharmacological and non-pharmacological pain management approaches may be useful. Patient education has a significant role to play in the avoidance of late neurological complications. Copyright © 2003 John Wiley & Sons, Ltd. [source] Pharmacokinetics of Gabapentin during Delivery, in the Neonatal Period, and Lactation: Does a Fetal Accumulation Occur during Pregnancy?EPILEPSIA, Issue 10 2005Inger Öhman Summary:,Purpose: To study the pharmacokinetics of gabapentin (GBP) during delivery, lactation, and in the neonatal period. Methods: GBP concentrations in plasma and breast milk were determined with high-performance liquid chromatography in samples from six women treated with GBP and in their offspring. Blood samples were obtained at delivery from mothers, from the umbilical cord, and from the newborns on three occasions during 2 days after delivery. GBP concentration also was determined in breast milk and in blood collected from five of the mothers and suckling infants 2 weeks to 3 months after birth. Results: The umbilical cord/maternal plasma concentration ratios ranged from 1.3 to 2.1 (mean, 1.7). GBP plasma concentrations in the neonates declined with an estimated half-life of 14 h. Mean GBP plasma concentrations in the infants were 27% of the cord plasma levels (range, 12,36%) 24 h postpartum. The mean milk/maternal plasma concentration ratio was 1.0 (range, 0.7,1.3) from 2 weeks to 3 months. The infant dose of GBP was estimated to 0.2,1.3 mg/kg/day, equivalent to 1.3,3.8% of the weight-normalized dose received by the mother. The plasma concentrations in the breast-fed infants were ,12% of the mother's plasma levels, but no adverse effects were observed. Conclusions: Our limited observations suggest an active transplacental transport of GBP, with accumulation in the fetus as a consequence. We suggest that this could be by the specific L-type amino acid transporter 1 (LAT-1), which is expressed in the placenta. Newborns seem to have a slightly lower capacity to eliminate GBP than do adults. Transfer of GBP to breast milk is extensive, but plasma concentrations appear to be low in suckling infants. No adverse effects were observed in the newborn. Although more data are needed, our observations suggest that breastfeeding in conjunction with GBP treatment is safe. [source] Vigabatrin, but not Gabapentin or Topiramate, Produces Concentration-related Effects on Enzymes and Intermediates of the GABA Shunt in Rat Brain and RetinaEPILEPSIA, Issue 7 2003Graeme J. Sills Summary: Purpose: The antiepileptic drug (AED) vigabatrin (VGB), which exerts its pharmacologic effects on the ,-aminobutyric acid (GABA) system, causes concentric visual field constriction in >40% of exposed adults. This may be a class effect of all agents with GABA-related mechanisms of action. We compared the concentration-related effects of VGB in rat brain and eye with those of gabapentin (GBP) and topiramate (TPM), both of which have been reported to elevate brain GABA concentrations in humans. Methods: Adult male rats (n = 10) were administered 0.9% saline (control), VGB (250, 500, 1,000 mg/kg), GBP (50, 100, 200 mg/kg), or TPM (12.5, 25, 50, 100 mg/kg). At 2 h after dosing, animals were killed, a blood sample obtained, the brain dissected into eight distinct regions, and the retina and vitreous humor isolated from each eye. Samples were analyzed for several GABA-related neurochemical parameters, and serum and tissue drug concentrations determined. Results: VGB treatment produced a significant (p < 0.05) dose-related increase in GABA concentrations and decrease in GABA-transaminase activity in all tissues investigated. This effect was most pronounced in the retina, where VGB concentrations were 18.5-fold higher than those in brain. In contrast, GBP and TPM were without effect on any of the neurochemical parameters investigated and did not accumulate appreciably in the retina. Conclusions: These findings corroborate a previously reported accumulation of VGB in the retina, which may be responsible for the visual field constriction observed clinically. This phenomenon does not appear to extend to other GABAergic drugs, suggesting that these agents might not cause visual field defects. [source] Comparative Cognitive Effects of Carbamazepine and Gabapentin in Healthy Senior AdultsEPILEPSIA, Issue 6 2001Roy Martin Summary: ,Purpose: This study compared the cognitive effects of carbamazepine (CBZ) and gabapentin (GBP) in healthy senior adults by using a randomized, double-blind crossover design. Methods: Thirty-four senior adults were randomized to receive one of the two drugs followed by a 5-week treatment period. A 4-week washout phase preceded initiation of the second drug. Antiepileptic drugs (AEDs) were titrated to target doses of either CBZ (800 mg/day) or GBP (2,400 mg/day). Primary outcome measures were standardized neuropsychological tests of attention/vigilance, psychomotor speed, motor speed, verbal and visual memory, and the Profile of Mood State (POMS), yielding a total of 17 variables. Each subject received cognitive testing at predrug baseline, end of first drug phase, end of second drug phase, and 4 weeks after completion of the second drug phase. Results: Fifteen senior adults (mean age, 66.5 years; range, 59,76 years) completed the study. Seniors completing the study did not differ significantly from noncompleting seniors in terms of demographic features or baseline cognitive performances. Fifteen of the 19 seniors not completing the study dropped out while receiving CBZ. Adverse events were frequently reported for both AEDs, although they were more common for CBZ. Mean serum levels for the completers were within midrange clinical doses (CBZ, 6.8 ,g/ml; GBP, 7.1 ,g/ml). Significant differences between CBZ and GBP were found for only one of 11 cognitive variables, with better attention/vigilance for GBP, although the effect was modest. Performances on the nondrug average were significantly better on 45% of cognitive variables compared with CBZ and 36% compared with GBP. The overall pattern of means favored GBP over CBZ on 15 of 17 (p < 0.001), nondrug over CBZ on 17 of 17 (p < 0.0000), and nondrug over GBP on eight of 17 (NS). Conclusions: Mild cognitive effects were found for both AEDs compared with the nondrug average condition. The magnitude of difference between the two AEDs across the cognitive variables was modest. Self-reported mood was not significantly affected by either AED. However, overall tolerability and side-effect profile of CBZ were poorer than those of GBP in senior adults at doses and titration rates reported in this study. [source] CLINICAL STUDY: Proof-of-concept human laboratory study for protracted abstinence in alcohol dependence: effects of gabapentinADDICTION BIOLOGY, Issue 1 2009Barbara J. Mason ABSTRACT There is a need for safe medications that can effectively support recovery by treating symptoms of protracted abstinence that may precipitate relapse in alcoholics, e.g. craving and disturbances in sleep and mood. This proof-of-concept study reports on the effectiveness of gabapentin 1200 mg for attenuating these symptoms in a non-treatment-seeking sample of cue-reactive, alcohol-dependent individuals. Subjects were 33 paid volunteers with current Diagnostic and Statistical Manual of Mental Disorders-IV alcohol dependence and a strength of craving rating 1 SD or greater for alcohol than water cues. Subjects were randomly assigned to gabapentin or placebo for 1 week and then participated in a within-subjects trial where each was exposed to standardized sets of pleasant, neutral and unpleasant visual stimuli followed by alcohol or water cues. Gabapentin was associated with significantly greater reductions than placebo on several measures of subjective craving for alcohol as well as for affectively evoked craving. Gabapentin was also associated with significant improvement on several measures of sleep quality. Side effects were minimal, and gabapentin effects were not found to resemble any major classes of abused drugs. Results suggest that gabapentin may be effective for treating the protracted abstinence phase in alcohol dependence and that a randomized clinical trial would be an appropriate next step. The study also suggests the value of cue-reactivity studies as proof-of-concept screens for potential antirelapse drugs. [source] The use of gabapentin in chronic cluster headache patients refractory to first-line therapyEUROPEAN JOURNAL OF NEUROLOGY, Issue 6 2007S. Schuh-Hofer Chronic cluster headache (CCH) is a rare but challenging condition. About 20% of CCH patients get refractory to treatment. Gabapentin has recently been reported to be efficacious in the treatment of CCH. To test the potential of gabapentin as second-line drug, we prospectively studied the efficacy of gabapentin as add-on drug in eight patients suffering from CCH refractory to first-line treatment. Six of eight CCH patients responded to treatment. After the end of the study phase, the patients' clinical course was further followed up until January 2006. The longest period of being continuously pain-free under gabapentin treatment was 18 months. In some individuals, increasing doses were needed with time. We conclude that gabapentin may be offered as treatment trial in patients refractory to first-line treatment. However, patients may fail to respond to treatment and drug tolerance may occur with time. [source] Antiepileptic Drugs in Migraine PreventionHEADACHE, Issue 2001Ninan T. Mathew MD Migraineurs may continue to experience attacks, despite daily use of one or more agents from a wide range of drugs, including , -blockers, calcium channel blockers, serotonin antagonists, tricyclic antidepressants, monoamine oxidase inhibitors, and antiepileptic agents. Divalproex sodium is the only antiepileptic drug approved for migraine prevention. Gabapentin, topiramate, and other antiepileptic agents are being evaluated for migraine prevention and treatment. Prospective, double-blind, placebo-controlled clinical trials of divalproex, gabapentin, and topiramate for migraine prevention generally were composed of a prospective baseline period, a dose titration period, and a fixed-dose treatment period. The primary efficacy variable was a reduction in the 28-day frequency of migraine headache. Patients receiving divalproex for 12 weeks at doses up to 1500 mg/day achieved significant decreases in the migraine frequency (P<.05), corresponding to reductions of 30% to 40% compared with baseline. Nearly half of the divalproex-treated patients had a 50% or more reduction from baseline in headache frequencies (P.05). Asthenia, vomiting, somnolence, tremor, and alopecia were common adverse events associated with divalproex. Significant reductions in migraine frequency were also observed with gabapentin (1800 to 2400 mg/day) when compared with placebo (P<.01), and nearly half of all patients treated at the highest dose experienced a reduction in headache rate of 50% or more. Somnolence was the most commonly reported adverse event among the gabapentin-treated patients. Two single-center, double-blind, placebo-controlled clinical trials evaluated topiramate for migraine prevention. A lower 28-day migraine frequency was seen during 18 weeks of administration at a maximum daily dose of 200 mg (P = .09). In a second study, a significantly lower mean 28-day migraine frequency was observed during 16 weeks of treatment with topiramate (P = .0015). Mean reduction in migraine frequency was also significantly greater in topiramate-treated patients (P = .0037). Paresthesias, diarrhea, somnolence, and altered taste were commonly reported adverse events in the topiramate-treated patients. Unlike some patients given divalproex or gabapentin, some given topiramate reported weight loss. Large, double-blind, placebo-controlled trials may prove the effectiveness of novel antiepileptic drugs in migraine prevention. [source] Adding Gabapentin to a multimodal regimen does not reduce acute pain, opioid consumption or chronic pain after total hip arthroplastyACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2009H. CLARKE Background: Gabapentin (GPN) is effective in reducing post-operative pain and opioid consumption, but its effects with regional anesthesia for total hip arthroplasty (THA) are not known. We designed this study to determine whether (1) gabapentin administration reduces pain and opioid use after THA using a multimodal analgesic regimen including spinal anesthesia; (2) pre-operative administration of gabapentin is more effective than post-operative administration. Methods: After REB approval and informed consent, 126 patients were enrolled in a double-blinded, randomized-controlled study. Patients received acetaminophen 1 g per os (p.o.), celecoxib 400 mg p.o. and dexamethasone 8 mg intravenously, 1,2 h pre-operatively. Patients were randomly assigned to one of three treatment groups (G1: Placebo/Placebo; G2: GPN/Placebo; G3: Placebo/GPN). Patients received gabapentin 600 mg (G2) or placebo (G1 and G3) 2 h before surgery. All patients had spinal anesthesia [15 mg (3cc) of 0.5% hypobaric bupivacaine with 10 ,g of fentanyl]. In the post-anesthetic care unit, patients received gabapentin 600 mg (G3) or placebo (G1 and G2). On the ward, patients received acetaminophen 1000 mg p.o. q6h, celecoxib 200 mg p.o. q12h and a morphine PCA device. Patients were interviewed 6 months post-surgery to determine the incidence and severity of chronic post-surgical pain. Results: Mean±SD cumulative morphine (mg) consumption (G1=49.4±24.8, G2=47.2±30.1 and G3=56.1±38.2) at 48 h and pain scores at 12, 24, 36 and 48 h post-surgery were not significantly different among the groups [G1 (n=38), G2 (n=38) and G3 (n=38)]. Side effect profiles were similar across groups. Six months after surgery, the number of patients who reported chronic post-surgical pain (G1=10, G2=12 and G3=9) and the severity of the pain (G1=4.2±2.9, G2=4.1±2.2 and G3=4.9±2.2) did not differ significantly among the groups (P>0.05). Conclusions: A single 600 mg dose of gabapentin given pre-operatively or post-operatively does not reduce morphine consumption or pain scores in hospital or at 6 months after hip arthroplasty within the context of spinal anesthesia and a robust multimodal analgesia regimen. [source] The pharmacology and epidemiology of post-market surveillance for suicide: the case of gabapentinJOURNAL OF PHARMACEUTICAL HEALTH SERVICES RESEARCH, Issue 2 2010Jill E. Lavigne Abstract Objectives, To describe the challenges in measurement of suicidal thoughts and behaviours and any causal relationship to prescription drug exposures. Recent US Food and Drug Administration (FDA) investigations of potential provocation of suicidal ideation and behaviour have led to black-box warnings of suicidal thoughts and behaviour on drugs ranging from smoking cessation to urinary incontinence agents. We describe the challenges faced in studying the effects of specific drug exposures on suicidal thoughts and behaviours using gabapentin (Neurontin) as an example because it has been implicated by the FDA as a drug that may induce suicidal thoughts or behaviours, offers more than 20 diverse indications including several known to be associated with an increase in suicide risk, and derives its clinical effect from 2 divergent mechanisms. Key findings, Gabapentin has two primary mechanisms: GABAergic neurotransmission and interruption of sodium and calcium channels. An increase in GABAergic neurotransmission is expected to improve anxiety and essential tremor, but to have no effect on pain, specifically migraine and neuropathic pain. Improvements in pain after gabapentin exposure are likely the result of the interruption of calcium and sodium channels. Neither mechanism is expected to affect bipolar disorder or schizophrenia, serious mental illnesses associated with a risk of suicide. Conclusions, These two independent mechanisms are expected to have mutually exclusive effects on a wide range of indications, only some of which are associated with increased risk of suicide. This very complexity and heterogeneity may present fertile ground for research aimed at not only improving our understanding of drug action, but also at expanding our knowledge of suicidal thoughts and behaviours. [source] A Double-Blind Trial of Gabapentin Versus Lorazepam in the Treatment of Alcohol WithdrawalALCOHOLISM, Issue 9 2009Hugh Myrick Introduction:, Some anticonvulsants ameliorate signs and symptoms of alcohol withdrawal, but have an unacceptable side effect burden. Among the advantages of using anticonvulsant agents in this capacity is their purported lack of interaction with alcohol that could increase psychomotor deficits, increase cognitive impairment, or increase intoxication. The aim of this study was to evaluate alcohol use and symptom reduction of gabapentin when compared with lorazepam in the treatment of alcohol withdrawal in a double-blinded randomized clinical trial. Methods:, One hundred individuals seeking outpatient treatment of alcohol withdrawal with Clinical Institute Withdrawal Assessment for Alcohol,Revised (CIWA-Ar) ratings ,10 were randomized to double-blind treatment with 2 doses of gabapentin (900 mg tapering to 600 mg or 1200 tapering to 800 mg) or lorazepam (6 mg tapering to 4 mg) for 4 days. Severity of alcohol withdrawal was measured by the CIWA-Ar on days 1 to 4 of treatment and on days 5, 7, and 12 post-treatment and alcohol use monitored by verbal report and breath alcohol levels. Results:, CIWA-Ar scores decreased over time in all groups; high-dose gabapentin was statistically superior but clinically similar to lorazepam (p = 0.009). During treatment, lorazepam-treated participants had higher probabilities of drinking on the first day of dose decrease (day 2) and the second day off medication (day 6) compared to gabapentin-treated participants (p = 0.0002). Post-treatment, gabapentin-treated participants had less probability of drinking during the follow-up post-treatment period (p = 0.2 for 900 mg and p = 0.3 for 1200 mg) compared to the lorazepam-treated participants (p = 0.55). The gabapentin groups also had less craving, anxiety, and sedation compared to lorazepam. Conclusions:, Gabapentin was well tolerated and effectively diminished the symptoms of alcohol withdrawal in our population especially at the higher target dose (1200 mg) used in this study. Gabapentin reduced the probability of drinking during alcohol withdrawal and in the immediate postwithdrawal week compared to lorazepam. [source] Pharmacokinetic profile and behavioral effects of gabapentin in the horseJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 5 2010R. L. TERRY Terry, R. L., McDonnell, S. M., van Eps, A. W., Soma, L. R., Liu, Y., Uboh, C. E., Moate, P. J., Driessen, B. Pharmacokinetic profile and behavioral effects of gabapentin in the horse. J. vet. Pharmacol. Therap. 33, 485,494. Gabapentin is being used in horses although its pharmacokinetic (PK) profile, pharmacodynamic (PD) effects and safety in the equine are not fully investigated. Therefore, we characterized PKs and cardiovascular and behavioral effects of gabapentin in horses. Gabapentin (20 mg/kg) was administered i.v. or p.o. to six horses using a randomized crossover design. Plasma gabapentin concentrations were measured in samples collected 0,48 h postadministration employing liquid chromatography-tandem mass spectrometry. Blood pressures, ECG, and sedation scores were recorded before and for 12 h after gabapentin dosage. Nineteen quantitative measures of behaviors were evaluated. After i.v. gabapentin, the decline in plasma drug concentration over time was best described by a 3-compartment mammillary model. Terminal elimination half-life (t1/2,) was 8.5 (7.1,13.3) h. After p.o. gabapentin terminal elimination half-life () was 7.7 (6.7,11.9) h. The mean oral bioavailability of gabapentin (±SD) was 16.2 ± 2.8% indicating relatively poor absorption of gabapentin following oral administration in horses. Gabapentin caused a significant increase in sedation scores for 1 h after i.v. dose only (P < 0.05). Among behaviors, drinking frequency was greater and standing rest duration was lower with i.v. gabapentin (P < 0.05). Horses tolerated both i.v. and p.o. gabapentin doses well. There were no significant differences in and . Oral administration yielded much lower plasma concentrations because of low bioavailability. [source] ,Protective premedication': an option with gabapentin and related drugs?ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2004A review of gabapentin, pregabalin in the treatment of post-operative pain Substantial progress has been made during the last decades in our understanding of acute pain mechanisms, and this knowledge has encouraged the search for novel treatments. Of particular interest has been the observation that tissue injury initiates a number of modulations of both the peripheral and the central pain pathways, which convert the system from a ,physiological' to a ,pathological' mode of processing afferent information. Gabapentin, which binds to the ,2, subunit of the voltage-dependent calcium channel, is active in animal models of ,pathological' but not in models of ,physiological' pain. Consequently, attention has so far been focused on neuropathic pain as a target for the clinical use of gabapentin and analogues. Recently, several reports have indicated that gabapentin may have a place in the treatment of post-operative pain. This article presents a brief summary of the potential mechanisms of post-operative pain, and a systematic review of the available data of gabapentin and pregabalin for post-operative analgesia. It is concluded that the results with gabapentin and pregabalin in post-operative pain treatment published so far are promising. It is suggested that future studies should explore the effects of ,protective premedication' with combinations of various antihyperalgesic and analgesic drugs for post-operative analgesia. [source] Painful neuropathy alters the effect of gabapentin on sensory neuron excitability in ratsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2004A. Kanai Background:, Pain following peripheral nerve injury is associated with increased excitability of sensory neurons. Gabapentin (GBP), a novel anticonvulsant with an uncertain mechanism of action, is an effective treatment for neuropathic pain. We therefore investigated the effect of GBP on dorsal root ganglion (DRG) neurons from normal rats and those with painful peripheral nerve injury. Methods:, Dorsal root ganglions were excised from rats with neuropathic pain behaviour following chronic constriction injury (CCI) of the sciatic nerve, and from normal rats. Intercellular recordings were made from myelinated sensory neuron somata using a microelectrode technique from DRGs bathed in artificial CSF with or without GBP (100 µM). Results:, Compared with normal neurons, injury decreased the refractory interval (RI) for repeat action potential (AP) generation increased the number of APs during sustained depolariza- tion, and shortened the after hyperpolarization following an AP. In normal neurons, GBP decreased the RI and increased the AP number during sustained depolarization. In an opposite fashion, the result of GBP application to injured neurons was a decreased number of APs during depolarization and no change in RI. In injured neurons only, GBP increased the time-to-peak for AP depolarization. Conclusions:, Nerve injury by CCI is associated with increased sensory neuron excitability, associated with a decreased AHP. In normal peripheral sensory neurons, GBP has pro-excitatory effects, whereas GBP decreases excitability in injured neurons, possibly on the basis of altered sodium channel function. [source] Effects of gabapentin on postoperative morphine consumption and pain after abdominal hysterectomy: A randomized, double-blind trialACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2004G. Dierking Background: Preliminary clinical studies have suggested that gabapentin may produce analgesia and reduce the need for opioids in postoperative patients. The aim of the present study was to investigate the opioid-sparing and analgesic effects of gabapentin administered during the first 24 h after abdominal hysterectomy. Methods: In a randomized, double-blind study, 80 patients received oral gabapentin 1200 mg or placebo 1 h before surgery, followed by oral gabapentin 600 mg or placebo 8, 16 and 24 h after the initial dose. Patients received patient-controlled analgesia with morphine at doses of 2.5 mg with a lock-out time of 10 min for 24 h postoperatively. Pain was assessed on a visual analogue scale (VAS) at rest and during mobilization, nausea, somnolence and dizziness on a four-point verbal scale, and vomiting as present/not present at 2, 4, 22 and 24 h postoperatively. Results: Thirty-nine patients in the gabapentin group, and 32 patients in the placebo group completed the study. Gabapentin reduced total morphine consumption from median 63 (interquartile range 53,88) mg to 43 (28,60) mg (P < 0.001). We observed a significant inverse association between plasma levels of gabapentin at 2 h postoperatively, and morphine usage from 0 to 2 h, and from 0 to 4 h postoperatively (R2 = 0.30, P = 0.003 and R2 = 0.24 P = 0.008, respectively). No significant differences in pain at rest or during mobilization, or in side-effects, were observed between groups. Conclusion: Gabapentin in a total dose of 3000 mg, administered before and during the first 24 h after abdominal hysterectomy, reduced morphine consumption with 32%, without significant effects on pain scores. No significant differences in side-effects were observed between study-groups. [source] Gabapentin can improve postural stability and quality of life in primary orthostatic tremorMOVEMENT DISORDERS, Issue 7 2005Julian P. Rodrigues MD Abstract Primary orthostatic tremor (OT) is characterized by leg tremor and instability on standing. High frequency (13,18 Hz) tremor bursting is present in leg muscles during stance, and posturography has shown greater than normal sway. We report on an open-label add-on study of gabapentin in 6 patients with OT. Six patients were studied with surface electromyography, force platform posturography, and a modified Parkinson's disease questionnaire (PDQ-39) quality of life (QOL) scale before and during treatment with gabapentin 300 mg t.d.s. If on other medications for OT, these were continued unchanged. Of the 6 patients, 4 reported a subjective benefit of 50 to 75% with gabapentin, 3 of whom showed reduced tremor amplitude and postural sway of up to 70%. Dynamic balance improved in all 3 patients who completed the protocol. QOL data from 5 patients showed improvement in all cases. No adverse effects were noted. Gabapentin may improve tremor, stability, and QOL in patients with OT, and symptomatic response correlated with a reduction in tremor amplitude and postural sway. The findings confirm previous reports of symptomatic benefit with gabapentin and provide justification for larger controlled clinical trials. Further work is required to establish the optimal dosage and to validate the methods used to quantify the response to treatment. © 2005 Movement Disorder Society [source] Using gabapentin to treat failed back surgery syndrome caused by epidural fibrosis: A report of 2 cases. (University of Pennsylvania Health System, School of Medicine, Pennsylvania, PA).PAIN PRACTICE, Issue 4 2001Arch Phys Med Rehabil. Failed back surgery syndrome (FBSS) is a long-lasting often disabling, and relatively frequent (5% to 10%) complication of lumdosacral spine surgery. Epidural fibrosis is among the most common causes of FBSS, and it is often recalcitrant to treatment. Repeated surgery for fibrosis has only a 30% to 35% success rate, whereas 15% to 20% of patients report worsening of their symptoms. Long-term outcome studies focusing on pharmacologic management of chronic back pain secondary to epidural fibrosis are lacking in the literature. This report presented 2 cases of severe epidural fibrosis managed successfully with gabapentin monotherapy. In both cases, functional status improved markedly and pain was significantly diminished. Gabapentin has an established, favorable safety profile and has been shown to be effective in various animal models and human studies of chronic neuropathic pain. Conclude clinicians should consider gabapentin as a pharmacological treatment alternative in the management of FBSS caused by epidural fibrosis. [source] Gabapentin in Comorbid Anxiety and Substance UseTHE AMERICAN JOURNAL ON ADDICTIONS, Issue 2 2007Marcia L. Verduin MD No abstract is available for this article. [source] Effect of Gabapentin on the Sensation and Impact of Tinnitus,THE LARYNGOSCOPE, Issue 5 2006Carol A. Bauer MD Abstract Objectives/Hypothesis: This study evaluated the effectiveness of gabapentin in treating chronic tinnitus in two populations: participants with tinnitus with associated acoustic trauma and participants with tinnitus without associated acoustic trauma. The hypothesis was that gabapentin would decrease both subjective and objective features of tinnitus in the trauma group but would be less effective in the nontrauma group. Study Design: Prospective, placebo-controlled, single-blind clinical trial. Methods: Pure-tone audiograms and personal histories were used to categorize tinnitus etiology as either secondary to acoustic trauma or not associated with acoustic trauma. Participants were restricted to those with moderate to severe tinnitus for at least 1 year. All participants received gabapentin in a graduated ascending-descending dose series extending over 20 weeks (peak dose of 2,400 mg/d). Results: There was a significant improvement in tinnitus annoyance for the trauma group (P = .05). Other subjective aspects of tinnitus were not significantly affected in either group. Between-subject variability of therapeutic response was considerable. Nevertheless, in consideration of subjective loudness ratings, 4 of 19 nontrauma participants and 6 of 20 trauma participants showed an improvement of 20% or better. In consideration of psychoacoustic loudness estimates, 3 of 19 nontrauma and 6 of 20 trauma participants showed an improvement of 20 dB HL or greater. Evenly dividing each group into high and low responders revealed significant improvement in loudness at 1,800 and 2,400 mg/day for the trauma high-response subgroup (P = .007). No significant improvement was obtained for other subgroups. Conclusion: Gabapentin is effective in reducing subjective and objective aspects of tinnitus in some individuals, with the best therapeutic response obtained in individuals with associated acoustic trauma. [source] Gabapentin withdrawal syndrome in the presence of a taperBIPOLAR DISORDERS, Issue 3 2005Kien T Tran Objective:, To report a case report of a geriatric patient with a 5-year history of gabapentin use for enhanced bipolar control, who was tapered off of gabapentin over 1 week. The patient displayed unique withdrawal symptoms after the taper of gabapentin. Methods:, The patient is an 81-year-old white female with a life-long history of schizoaffective disorder with bipolar type I tendencies who had been prescribed gabapentin for 5 years. Results:, The patient displayed moderate upper respiratory tract infection symptoms and somatic complaints 1 day after termination of gabapentin. These symptoms gradually worsened until 10 days after, at which time she acutely developed severe mental status changes, severe somatic chest pain, and hypertension. Physical examination, electrolytes, electrocardiogram, computerized tomography, magnetic resonance imaging, and magnetic resonance angiography were all normal. Upon reintroduction of gabapentin, the patient returned to baseline within 1,2 days. Conclusions:, Gabapentin is widely utilized currently for the chronic treatment of recalcitrant migraines, bipolar illness, pain, and epilepsy. It has a wide therapeutic index with few side effects and drug interactions, is not hepatically metabolized, and is excreted by the kidneys. Past reports have suggested that some withdrawal symptoms can present after 1,2 days upon abrupt discontinuation of gabapentin after chronic use within young to middle-aged patients. These symptoms mimic that of alcohol and benzodiazepine withdrawal purportedly due to a similar mechanism of action. Unique to this case is that this geriatric patient developed debilitating withdrawal symptoms after a gradual, week-long taper of gabapentin along with flu-like symptoms. It is proposed herein that a gabapentin taper should follow a course similar to that of a benzodiazepine taper , slowly and over a period of weeks to months. [source] A comparison of Ca2+ channel blocking mode between gabapentin and verapamil: implication for protection against hypoxic injury in rat cerebrocortical slicesBRITISH JOURNAL OF PHARMACOLOGY, Issue 2 2003Michiko Oka The mode of Ca2+ channel blocking by gabapentin [1-(aminomethyl)cyclohexane acetic acid] was compared to those of other Ca2+ channel blockers, and the potential role of Ca2+ channel antagonists in providing protection against hypoxic injury was subsequently investigated in rat cerebrocortical slices. mRNA for the ,2, subunits of Ca2+ channels was found in rat cerebral cortex. Nitric oxide (NO) synthesis estimated from cGMP formation was enhanced by KCl stimulation, which was mediated primarily by the activation of N- and P/Q-type Ca2+ channels. Gabapentin blocked both types of Ca2+ channels, and preferentially reversed the response to 30 mM K+ stimulation compared with 50 mM K+ stimulation. In contrast, verapamil preferentially inhibited the response to depolarization by the higher concentration (50 mM) of K+. Gabapentin inhibited KCl-induced elevation of intracellular Ca2+ in primary neuronal culture. Hypoxic injury was induced in cerebrocortical slices by oxygen deprivation in the absence (severe injury) or presence of 3 mM glucose (mild injury). Gabapentin preferentially inhibited mild injury, while verapamil suppressed only severe injury. , -Conotoxin GVIA (, -CTX) and , -agatoxin IVA (, -Aga) were effective in both models. NO synthesis was enhanced in a manner dependent on the severity of hypoxic insults. Gabapentin reversed the NO synthesis induced by mild insults, while verapamil inhibited that elicited by severe insults. , -CTX and , -Aga were effective in both the cases. Therefore, the data suggest that gabapentin and verapamil cause activity-dependent Ca2+ channel blocking by different mechanisms, which are associated with their cerebroprotective actions and are dependent on the severity of hypoxic insults. British Journal of Pharmacology (2003) 139, 435,443. doi:10.1038/sj.bjp.0705246 [source] Retention rates of new antiepileptic drugs in localization-related epilepsy: a single-center studyACTA NEUROLOGICA SCANDINAVICA, Issue 1 2009J. Peltola Objectives,,, We evaluated long-term retention rates of newer antiepileptic drugs (AED) in adults with localization-related epilepsy retrospectively. Methods,,, We estimated retention rates by Kaplan,Meier method in all 222 patients (age , 16) with localization-related epilepsy exposed to new AED at the Tampere University Hospital. Results,,, There were 141 patients exposed to lamotrigine, 78 to levetiracetam, 97 to topiramate, 68 to gabapentin, and 69 to tiagabine. Three-year retention rate for lamotrigine was 73.5%, levetiracetam 65.4%, topiramate 64.2%, gabapentin 41.7%, and tiagabine 38.2%. The most common cause for withdrawal of these AED was lack of efficacy. Conclusions,,, Our study suggests that there are clinically significant differences among gabapentin, lamotrigine, levetiracetam, tiagabine, and topiramate as treatment for focal epilepsy in everyday practice. Gabapentin and tiagabine seem to be less useful than the other three AED. Furthermore, our study supports the value of retention rate studies in assessing outcome of the drugs in clinical practice. [source] The P/Q-type voltage-dependent calcium channel: a therapeutic target in spinocerebellar ataxia type 6ACTA NEUROLOGICA SCANDINAVICA, Issue 5 2007J. Gazulla Background,,, Voltage-dependent calcium channels (VDCCs) are heteromultimeric complexes that mediate calcium influx into cells; the ,1A subunit is the pore-forming subunit specific to the neuronal P/Q-type VDCCs. Spinocerebellar ataxia type 6 (SCA 6) is caused by an abnormal expansion of a CAG repeat in CACNA1A, which encodes the ,1A subunit. Heterologous expression of mutated ,1A subunits resulted in increased channel inactivation in electrophysiological tests. Gabapentin and pregabalin interact with the ,2, subunit of the VDCCs and improved ataxia in cases of cortical cerebellar atrophy (CCA) and ataxia-telangiectasia. Materials and methods,,, A bibliographical review was performed in order to find out if gabapentin and pregabalin coud prove useful in the treatment of SCA 6. Results,,, Gabapentin and pregabalin slowed the rate of inactivation in recombinant P/Q-type VDCCs. SCA 6 shares neuropathological findings with CCA. Conclusions,,, On the basis of the neuropathological identity of SCA 6 with CCA, and of the effect of gabapentin and pregabalin on recombinant VDCCs the authors put forward the hypothesis that these drugs might prove beneficial in SCA 6, as the ataxia would be expected to improve. The authors hope that researchers working with this illness will be encouraged to undertake the appropriate clinical and experimental work. [source] Therapeutic Hotline: Treatment of prurigo nodularis and lichen simplex chronicus with gabapentinDERMATOLOGIC THERAPY, Issue 2 2010Gulsum Gencoglan ABSTRACT Psychocutaneous conditions are frequently encountered in dermatology practice. Prurigo nodularis and lichen simplex chronicus are two frustrating conditions that are classified in this category. They are often refractory to classical treatment with topical corticosteroids and antihistamines. Severe, generalized exacerbations require systemic therapy. Phototherapy, erythromycine, retinoids, cyclosporine, azathiopurine, naltrexone, and psychopharmacologic agents (pimozide, selective serotonin reuptake inhibitor antidepressants) were tried with some success. Here five cases with lichen simplex chronicus and four cases with prurigo nodularis, who responded well to gabapentin, are presented. [source] Weight gain in bipolar disorder: pharmacological treatment as a contributing factorACTA PSYCHIATRICA SCANDINAVICA, Issue 1 2008C. Torrent Objective:, The aim of this paper was to review the association of most commonly used psychopharmacological drugs with weight gain in bipolar disorder. Method:, Information was retrieved from a PubMed/Medline literature search reviewing weight gain in pharmacological studies in bipolar disorder. Results:, Obesity and overweight in bipolar disorder are partly related to prescribed drugs with a strong effect of clozapine and olanzapine. Lesser but still relevant weight gain is caused by quetiapine, risperidone, lithium, valproate, gabapentin and by some antidepressants. Ziprasidone, aripiprazole, carbamazepine and lamotrigine do not seem to cause significant overweight. Conclusion:, Careful monitoring of weight changes in patients before and after drug prescription should be implemented in the clinical routine and drugs which potentially cause weight gain should be avoided in overweight patients with bipolar disorder. Furthermore, eating habits and daily activities should be targeted as they may also have a significant impact on overall health and weight-related issues. [source] Antiepileptic drugs in the preventive treatment of migraine in children and adolescentsDRUG DEVELOPMENT RESEARCH, Issue 6 2007Catello Vollono Abstract Migraine prevalence in childhood ranges from 2.7 to 10% causing a significant impact on quality of life. No drugs are currently approved for use in the prevention of pediatric migraine. Antiepileptic drugs such as valproate and topiramate have been approved for the preventive treatment of migraine in adults. The present study aimed at reviewing evidence on the efficacy and safety of antiepileptic drugs in the preventive treatment of migraine in children and adolescents. We searched PubMed from 1988 to May 2007 and reviewed, abstracted, and classified relevant literature. Thirteen studies were reviewed. Data from randomized controlled trials are available only for valproate and topiramate. They show that both topiramate and valproate are effective in reducing headache frequency, intensity, and duration. As for safety and tolerability, topiramate is well tolerated, while there are insufficient data regarding the tolerability of valproate. Open-label or retrospective studies suggest that levetiracetam, zonisamide, and gabapentin are effective, but further evidence is warranted to confirm these data. Drug Dev Res 68:355,359, 2007. © 2007 Wiley-Liss, Inc. [source] Antiepileptic drugs combined with high-frequency electrical stimulation in the ventral hippocampus modify pilocarpine-induced status epilepticus in ratsEPILEPSIA, Issue 3 2010Manola Cuellar-Herrera Summary Purpose:, To evaluate the effects of high-frequency electrical stimulation (HFS) in both ventral hippocampi, alone and combined with a subeffective dose of antiepileptic drugs, during the status epilepticus (SE) induced by lithium-pilocarpine (LP). Methods:, Male Wistar rats, stereotactically implanted in both ventral hippocampi, were injected with pilocarpine (30 mg/kg, i.p.) 24 h after lithium (3 mEq/kg) administration. One minute following pilocarpine injection, HFS (pulses of 60 ,s width at 130 Hz at subthreshold intensities and applied during 3 h) was applied alone or combined with subeffective doses of antiepileptic drugs. Results:, HFS alone reduced the incidence of severe generalized seizures. This effect was not evident when HFS was combined with phenytoin (33.3 mg/kg, i.p.). HFS combined with diazepam (0.41 mg/kg, i.p.) or phenobarbital (10 mg/kg, i.p.) reduced the incidence of severe generalized seizures and mortality rate, and augmented the latency to first forelimb clonus, generalized seizure, and status epilepticus (SE). When combined with gabapentin (46 mg/kg, i.p.), HFS reduced the incidence of severe generalized seizures, enhanced latency to SE, and decreased mortality rate. Discussion:, Subeffective doses of antiepileptic drugs that increase the ,-aminobutyric acid (GABA)ergic neurotransmission may represent a therapeutic tool to augment the HFS-induced anticonvulsant effects. [source] Clinical picture of EPM1-Unverricht-Lundborg diseaseEPILEPSIA, Issue 4 2008Reetta Kälviäinen Summary Unverricht-Lundborg disease (ULD), progressive myoclonic epilepsy type 1 (EPM1, OMIM254800), is an autosomal recessively inherited neurodegenerative disorder characterized by age of onset from 6 to 16 years, stimulus-sensitive myoclonus, and tonic,clonic epileptic seizures. Some years after the onset ataxia, incoordination, intentional tremor, and dysarthria develop. Individuals with EPM1 are mentally alert but show emotional lability, depression, and mild decline in intellectual performance over time. The diagnosis of EPM1 can be confirmed by identifying disease-causing mutations in a cysteine protease inhibitor cystatin B (CSTB) gene. Symptomatic pharmacologic and rehabilitative management, including psychosocial support, are the mainstay of EPM1 patients' care. Valproic acid, the first drug of choice, diminishes myoclonus and the frequency of generalized seizures. Clonazepam and high-dose piracetam are used to treat myoclonus, whereas levetiracetam seems to be effective for both myoclonus and generalized seizures. There are a number of agents that aggravate clinical course of EPM1 such as phenytoin aggravating the associated neurologic symptoms or even accelerating cerebellar degeneration. Sodium channel blockers (carbamazepine, oxcarbazepine) and GABAergic drugs (tiagabine, vigabatrin) as well as gabapentin and pregabalin may aggravate myoclonus and myoclonic seizures. EPM1 patients need lifelong clinical follow-up, including evaluation of the drug-treatment and comprehensive rehabilitation. [source] Pregabalin Exerts Oppositional Effects on Different Inhibitory Circuits in Human Motor Cortex: A Double-blind, Placebo-controlled Transcranial Magnetic Stimulation StudyEPILEPSIA, Issue 5 2006Nicolas Lang Summary:,Purpose: To explore acute effects of pregabalin (PGB) on human motor cortex excitability with transcranial magnetic stimulation (TMS). Methods: PGB, 600 mg/day, was orally administered in 19 healthy subjects twice daily in a randomized, double-blind, placebo-controlled crossover design. Several measures of motor cortex excitability were tested with single- and paired-pulse TMS. Results: Mean short-interval intracortical inhibition (SICI) was reduced after PGB (74 ± 7% of unconditioned response) compared with placebo (60 ± 6% of unconditioned response). In contrast, mean long-interval intracortical inhibition (LICI) was increased by PGB (26 ± 4% of unconditioned response) compared with placebo (45 ± 8% of unconditioned response), and mean cortical silent period (CSP) showed an increase from 139 ± 8 ms or 145 ± 8 ms after placebo to 162 ± 7 ms or 161 ± 10 ms after PGB. Motor thresholds, intracortical facilitation, and corticospinal excitability were unaffected. Conclusions: The observed excitability changes with oppositional effects on SICI and LICI or CSP suggest ,-aminobutyric acid (GABA)B -receptor activation. They are markedly distinct from those induced by gabapentin, although both PGB and gabapentin are thought to mediate their function by binding to the ,(2)-, subunit of voltage-gated calcium channels. Conversely, the TMS profile of PGB shows striking similarities with the pattern evoked by the GABA-reuptake inhibitor tiagabine. [source] | |||||||||||||||||||||||||||||||||||||||||||