Gabapentin In Patients Research Articles

The efficacy and safety of gabapentin in carpal tunnel patients: Open label trial

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy caused by median nerve compression at the wrist. It results in loss of considerable man days and the effectiveness the various treatment modalities are still debated. To study the efficacy of gabapentin in patients with CTS. The study aim is to investigate the efficacy of gabapentin in patients with CTS patients who were refractory to the other conservative measures or unwilling for the surgical procedure. Forty one patients diagnosed as idiopathic CTS were included in the study. Patients were assessed with symptom severity scale (SSS) and functional status scale (FSS) scores of Boston Carpal Tunnel Questionnaire (BCTQ) before and at 1, 3, and 6 months of the treatment. Response to therapy was determined by using SSS and FSS scores of BCTQ. The median dosage of gabapentin was 1800 mg/daily. Side effects were mild and transient. There was a statistically significant difference in both symptom SSS and FSS scores between before and after treatment in patient groups at the end of six months (P < 0.001). According to grading the changes in subscales of BCTQ, of 41 patients, 34.1 and 29.3 had a >or= 40% decrease in SSS and FSS, respectively. Gabapentin was found to be partially effective and safe in symptomatic treatment of CTS patients.

A single dose of preoperative gabapentin for pain reduction and requirement of morphine after total mastectomy and axillary dissection

Gabapentin has been recently found to be useful for reducing acute postoperative pain when administered preoperatively. Although various dose regimens have been tried in different surgical settings, the minimum effective dose is not established. We aimed to evaluate the analgesic efficacy of single low dose gabapentin in patients undergoing total mastectomy and axillary dissection. Prospective randomized placebo-controlled double-blind trial in a tertiary care teaching hospital. Fifty women scheduled for total mastectomy and axillary dissection were randomized to receive either gabapentin 600 mg or placebo orally 1 h preoperatively. The intraoperative and postoperative management was standardized. Postoperative pain was assessed at rest and on movement for 12 h using the numerical rating scale (NRS). Morphine was administered if NRS exceeded 30. Primary outcome measure was total morphine consumption. The morphine consumption was compared using independent t test while pain and sedation scores were analyzed using Mann-Whitney U test. Forty-six patients completed the trial. The postoperative morphine consumption was significantly less (5.8 +/- 4.2 vs. 11.0 +/- 3.4 mg; P 0.001) and the median [IQR] time to first analgesic was significantly longer (90 [37.5-120] vs. 0 [0-90] min; P 0.001) in the gabapentin group than in the placebo group. The incidence of side effects was similar in the two groups. A single low dose of 600 mg gabapentin administered 1 h prior to surgery produced effective and significant postoperative analgesia after total mastectomy and axillary dissection without significant side effects.

Effect of add‐on gabapentin on opioid withdrawal symptoms in opium‐dependent patients

Evaluation of the efficacy of gabapentin in patients undergoing out-patient treatment for opiate withdrawal. A 3-week double-blind, randomized, placebo-controlled trial of adjunctive gabapentin in methadone-assisted detoxification (MAD). Specialized Addictive Behaviors Unit, an out-patient unit for the treatment of patients with an addictive disorder serving the city of Isfahan (Iran). Forty out-patients, 37 males and three females, aged 21-61 years, who met DSM-IV criteria for opiate dependence. Random assignment of subjects to receive adjunctive treatment with either gabapentin (900 mg/day) or placebo under double-blind conditions. Severity of subjective withdrawal symptoms using the Subjective Opiate Withdrawal Scale at six stages. Despite the superiority of gabapentin on controlling some of withdrawal symptoms, no significant differences were reported between two groups. Dosage of 900 mg/day of gabapentin is not significantly superior to placebo in controlling opiate withdrawal symptoms.

Effects of Gabapentin in Patients with Neuropathic Pain Syndromes

Effects of Gabapentin in Patients with Neuropathic Pain Syndromes

The Analgesic Effects of Preemptive Gabapentin in Patients Undergoing Surgery for Brachial Plexus Injury—A Preliminary Study

There are reports indicating that gabapentin may have place in the treatment of postoperative pain. No study has evaluated the effects of gabapentin on acute, postoperative pain in patients undergoing surgery for brachial plexus injuries. In this preliminary study, we evaluated gabapentin as preemptive analgesic for intraoperative period and during the acute postoperative period at rest and during movement. Twenty consecutive adult patients undergoing surgery for brachial plexus injury were enrolled for the study. Patients randomly received either oral gabapentin 800 mg or placebo capsules 2 hours before surgery. General anesthesia was induced and maintained with propofol, at bispectral index value between 40 and 60. Intraoperative fentanyl and propofol requirements were noted. Postoperatively, all patients were alert and pain was assessed using visual analog scale (VAS) for 24 hours, both during rest and movement. Whenever VAS score was more than 50 or on patients' demand, ketorolac 30 mg was given as rescue analgesic. The demographics, duration of surgery, and propofol consumption in both groups were comparable. Intraoperative and postoperative heart rate and mean blood pressure were also comparable. Significant difference was noted in intraoperative fentanyl consumption (P=0.03), total dose of rescue analgesic (P=0.004), and VAS score at rest and movement, between the 2 groups; less in gabapentin group as compared with placebo group (P=0.01 and 0.04, at rest and movement, respectively). A single oral dose of gabapentin 800 mg, as preemptive analgesic in patients undergoing surgery for brachial plexus injury is found to be an effective adjunct to intraoperative and postoperative pain. Pain is reduced not only at rest but also during movement.

(722): Initial use of pregabalin and gabapentin in patients with diabetic neuropathy or postherpetic neuralgia: Achieving the minimally effective dose

Pregabalin and gabapentin, two α 2-delta ligands, have demonstrated efficacy in neuropathic pain associated with diabetic peripheral neuropathy (DPN) and postherpetic neuralgia (PHN). However, pregabalin has nonsaturable absorption at clinically relevant doses, resulting in linear pharmacokinetics and a more predictable exposure compared to gabapentin. Our objective was to compare the attainment of labeled minimally effective dose levels among new users of pregabalin (≥150 mg/day in DPN and PHN) or gabapentin (≥1800 mg/day in PHN).

Gabapentin in the treatment of fibromyalgia: A randomized, double‐blind, placebo‐controlled, multicenter trial

To assess the efficacy and safety of gabapentin in patients with fibromyalgia. A 12-week, randomized, double-blind study was designed to compare gabapentin (1,200-2,400 mg/day) (n=75 patients) with placebo (n=75 patients) for efficacy and safety in treating pain associated with fibromyalgia. The primary outcome measure was the Brief Pain Inventory (BPI) average pain severity score (range 0-10, where 0=no pain and 10=pain as bad as you can imagine). Response to treatment was defined as a reduction of >or=30% in this score. The primary analysis of efficacy for continuous variables was a longitudinal analysis of the intent-to-treat sample, with treatment-by-time interaction as the measure of effect. Gabapentin-treated patients displayed a significantly greater improvement in the BPI average pain severity score (P=0.015; estimated difference between groups at week 12=-0.92 [95% confidence interval -1.75, -0.71]). A significantly greater proportion of gabapentin-treated patients compared with placebo-treated patients achieved response at end point (51% versus 31%; P=0.014). Gabapentin compared with placebo also significantly improved the BPI average pain interference score, the Fibromyalgia Impact Questionnaire total score, the Clinical Global Impression of Severity, the Patient Global Impression of Improvement, the Medical Outcomes Study (MOS) Sleep Problems Index, and the MOS Short Form 36 vitality score, but not the mean tender point pain threshold or the Montgomery Asberg Depression Rating Scale. Gabapentin was generally well tolerated. Gabapentin (1,200-2,400 mg/day) is safe and efficacious for the treatment of pain and other symptoms associated with fibromyalgia.

Should Gabapentin Be Dose Adjusted: What are the Clinical Consequences?

Objective: To review the clinical necessity of renal dose adjustment of gabapentin. Data Sources: Medical literature (1966–February 2006, week 2) was accessed through MEDLINE, EMBASE, Pre-MEDLINE, International Pharmaceutical Abstracts, and the manufacturer's package insert. Search terms included gabapentin, side effects/adverse effects, overdose, toxicity, and renal impairment. Literature references were consulted for relevant information. Study Selection and Data Extraction: All studies from the data sources that were published in English were evaluated. Case reports, case series, and clinical trials with primarily adult populations were included in the review to determine the clinical necessity of dosage adjustment, including morbidity and mortality associated with dose adjustment failure. Case reports of gabapentin overdose were evaluated for clinically significant outcomes. All reports were examined for clinical relevance and adequate information to address the issue of major clinical consequences of failure to dose adjust gabapentin in specific patient populations, including renally impaired and elderly patients. Data Synthesis: The package insert suggests dose adjustment of gabapentin in patients with decreased renal function, yet published information regarding clinical consequences of gabapentin in patients is limited. Although gabapentin possesses a favorable safety profile and is generally well tolerated, there have been cases reporting serious adverse effects. While clinical studies and the majority of case reports demonstrate minimal adverse effects, there is some concern that select patients may experience serious outcomes if the drug is not dose adjusted. Conclusions: The recommendation for dosage adjustment is suitably based upon the pharmacokinetic properties of gabapentin, yet healthcare practitioners should determine the need for gabapentin dosage adjustment in specific patients. There should be continued emphasis on recommending renal dose adjustments, with the most concern applied to the elderly and patients with significant renal impairment/end-stage renal disease.

The effect of oral gabapentin on postdural puncture headache

Summary Postdural puncture headache (PDPH) has been a vexing problem for patients undergoing dural puncture for spinal anaesthesia since Bier reported the first case in 1898. Gabapentin is a structural analogue of gamma-aminobutyricacid (GABA), which was first developed as an anticonvulsant drug. In this study, we investigated the efficacy and tolerability of administration of oral gabapentin in PDPH. Twenty ASA I–II patients who developed PDPH after spinal anaesthesia were included in this study. After PDPH was diagnosed by the postural component of the pain, all the patients were treated with bed rest and fluid hydration in postoperative care. Patients were randomised to receive either gabapentin (Group 1) or placebo (Group 2). Group 1 (n = 10) received 900 mg/day three times a day of gabapentin 300 mg (Neurontin; Pfizer) orally and the same dose was repeated every 8 h for 4 days. The patients’ headaches were evaluated by using the visual analogue scale (VAS) for 4 days. Other complications such as somnolence, ataxia, light-headedness, dizziness and visual disturbances were also followed. VAS scores were significantly lower in Group 1 than in Group 2 for the 4 days of the study. Administration of oral gabapentin in patients with PDPH after spinal anaesthesia is an effective and safe treatment.

22: The use of gabapentin in patients under intrathecal infusion of morphine and clonidine that developed opioid tolerance

22: The use of gabapentin in patients under intrathecal infusion of morphine and clonidine that developed opioid tolerance

Gabapentin in patients with the pruritus of cholestasis: A double-blind, randomized, placebo-controlled trial

Pruritus is defined as the second order of nociception, the first being pain; thus, there is a rationale to study gabapentin, a drug that increases the threshold to experience nociception. The aim of this double-blind, randomized, placebo-controlled trial was to study the effect of gabapentin on the perception of pruritus and its behavioral manifestation, scratching, in cholestasis. The participants were 16 women with chronic liver disease and chronic pruritus. Hourly scratching activity (HSA) was continuously recorded for up to 48 hours at baseline and on treatment for at least 4 weeks in an inpatient setting. The perception of pruritus was assessed by interviews and by a visual analog score (VAS) of pruritus recorded every hour while patients were awake. Patients were randomized to the study drug (gabapentin or placebo) at a starting dose of 300 mg orally per day in divided doses to a maximum of 2,400 mg or until relief from pruritus. Gabapentin was associated with an increase in mean HSA, in contrast to the placebo, which was associated with a decrease. The mean VAS decreased significantly among those taking the placebo and in some patients on gabapentin. In conclusion, gabapentin did not provide a significant therapeutic advantage over the placebo; in fact, it was associated with an increase in the perception of pruritus and in HSA in some patients.

A phase III double blinded, placebo controlled, randomized trial of gabapentin in patients with chemotherapy-induced peripheral neuropathy: A North Central Cancer Treatment Group study

8001 Background: The purpose of this study was to determine if gabapentin, an anti-convulsant used for neuropathic pain, is effective in improving pain and symptoms due to chemotherapy-induced peri...

The Safety and Effectiveness of Newer Antiepileptics: A Comparative Postmarketing Cohort Study

Clinical trials for the newer antiepileptic drugs (AEDs) have provided inconclusive information to evaluate comparative risk benefit. The authors use data from postmarketing observational cohort studies to compare the failure of treatment with lamotrigine, vigabatrin, and gabapentin in patients with refractory epilepsy. The Drug Safety Research Unit has conducted prescription event monitoring (PEM) studies for lamotrigine, vigabatrin, and gabapentin to monitor their safety when used in primary care. The primary outcome of this study was time to treatment failure in patients who had been prescribed the drug after the start of the PEM study. Patients on gabapentin had reduced time to treatment failure compared to those on the other 2 drugs. The age- and sex-adjusted hazard ratio of failure was 1.53 (95% confidence interval [CI] = 1.38-1.70) for gabapentin compared to lamotrigine and 1.19 (95% CI = 1.10-1.30) for vigabatrin compared to lamotrigine. The observed differences between the 3 study drugs might be confounded by a higher proportion of patients treated with gabapentin having refractory epilepsy, a shorter duration of the gabapentin PEM study, and a lower relative dose of gabapentin (approved at the time of the PEM study). The current study provides information about the routine usage of newer AEDs, which complements evidence from clinical trials regarding the efficacy and safety of these AEDs. Although this study showed differences on times to treatment failure between lamotrigine, vigabatrin, and gabapentin, the results are only useful when considered together with results from other studies seeking to answer the same questions.

The Efficacy of Gabapentin in Patients with Failed Back Surgery: A Prospective Case Series

Objective: Failed back surgery syndrome [FBSS] causes persistent low back problems in approximately 15 percent of patients who undergo spinal surgery for lumbar disc herniation. As reported by recent clinical data, gabapentin, an antiepileptic agent, is increasingly being used for chronic pain, with a favorable side effect profile. The aim of this study was to investigate the efficacy of gabapentin in patients with FBSS associated chronic back painMethods: Nine patients with chronic back pain diagnosed with FBSS according to clinical, lumbar spinal magnetic resonance imaging and electrodiagnostic findings were studied. Each patient received titrated dosage of gabapentin from 900 to 2400 mg/day. Pretreatment levels of pain and the degree of disability were measured using a visual analog scale and the Oswestry disability index. All nine patients were re-evaluated at six weeks and six monthsResults: Eight of nine patients reported significant decrease in pain and disability scores at six weeks and six months...

The effectiveness of gabapentin in patients with chronic radiculopathy

This study was carried out to determine the efficacy of gabapentin in patients with radiculopathy. Fifty patients (32 women, 18 men) with lumbosciatalgia secondary to L5 or S1 radiculopathy were evaluated. MRI showed L4-5 and/or L5-S1 bulging and/or protrusion without significant spinal stenosis. Baseline assessments for each patient included a standard neurological examination and radiological investigation. The patients were randomly assigned into two groups: group 1 was treated with oral gabapentin from a total of 900 mg per day up a total of 3600 mg per day divided in 3 doses; group 2 received placebo for the 8-week trial period. In group 1 we observed statistically significant improvement in pain at rest (p < 0.001), motor function (p < 0.01), limitation of spinal flexion (p < 0.001), straight leg raising test (p < 0.001) and sensory function (p < 0.001). Stretch reflexes instead did not significantly change. In group 2 we observed significant improvement in all clinical parameters, muscle strength and stretch reflexes excluded. The results of group 1 were significantly better than those of group 2.

Gabapentin: The First Preemptive Anti-Hyperalgesic for Opioid Withdrawal Hyperalgesia?

Departments of Anesthesiology and Pharmacology &amp; Toxicology, Queen's University, Kingston, Ontario, Canada. gilroni@post.queensu.caIn Reply:—The above letter responds to the provocative question of whether gabapentin is a “broad spectrum” analgesic 1and appropriately points out that things are not quite so simple.Gustorff et al. postulate that the effects of gabapentin reported by Dirks et al. 2are not due to antinociception but, rather, to the suppression of hyperalgesia caused by withdrawal from intraoperative opioids. This is a reasonable hypothesis; however, it should be noted that Fassoulaki et al. recently observed similar reductions in pain and opioid consumption with gabapentin in patients who received no intraoperative opioids. 3Therefore, gabapentin's effects cannot be solely due to suppression of opioid withdrawal hyperalgesia.Nevertheless, this raises questions central to understanding the modulation of pain by gabapentin. While Gustorff et al. correctly indicate that postoperative pain is predominantly nociceptive, they fail to emphasize the importance of spinal sensitization, 4which contributes to hyperalgesia and allodynia and which may be suppressed by gabapentin. Indeed, although gabapentin has little antinociceptive effect in the uninjured organism, it has been shown, in the absence of opioids, to reduce pain responses after surgical tissue injury. 5The latter comments by Gustorrf et al. illustrate the complexities of interpreting gabapentin's effect when administered with opioids. Ethical conduct of most postoperative trials requires the provision of rescue analgesia, often in the form of patient-controlled analgesia with morphine, which necessitates the integration of pain measures with morphine consumption as co-relevant outcome measures. 6Although trials have been equivocal thus far, 7,8the possibility that mechanisms of opioid tolerance 9contribute to postoperative hyperalgesia and increased opioid requirements may confound results of analgesic trials. Therefore, gabapentin trials involving concomitant morphine administration must be interpreted in light of a possible interaction between these drugs. In this regard, we have observed in the rat that gabapentin prevents the development of morphine tolerance and partially reverses established tolerance indicating that such an interaction indeed exists. 10Thus, although follow-up studies will further characterize the role of gabapentin in postoperative pain, even more sophisticated strategies are needed to distinguish between its specific pharmacological effects (e.g. , analgesia, antihyperalgesia, antiallodynia and reversal of opioid tolerance).

Gabapentin: in postherpetic neuralgia.

Gabapentin is a structural analogue of the neurotransmitter gamma-aminobutyric acid (GABA) approved for use in adults with postherpetic neuralgia. Gabapentin does not bind to GABA(A) or GABA(B) receptors. Its mechanism of action in humans is unclear, but may involve binding to alpha2delta calcium channel subunits in animal models. Reductions in the mean daily pain score from baseline to week 7 or 8 of treatment (primary endpoint) were significantly greater with gabapentin 1800-3600 mg/day than placebo therapy in two well designed trials in patients with postherpetic neuralgia. The proportion of responders (patients showing a > or =50% reduction in mean daily pain score at endpoint versus baseline) was significantly greater with gabapentin than placebo. Daily sleep rating scores, the Short Form McGill Pain Questionnaire (total pain scores), Patient and Clinician Global Impression of Change and measures on the Short Form-36 Health Survey (including physical functioning, role-physical, bodily pain, vitality or mental health) improved to a significantly greater extent with gabapentin than placebo. Adverse events associated with gabapentin in patients with postherpetic neuralgia were usually mild to moderate in intensity, with dizziness, somnolence and peripheral oedema being commonly reported.

Pilot Evaluation of Gabapentin for Treating Hot Flashes

To obtain pilot prospective data regarding the efficacy and tolerability of gabapentin for alleviating hot flashes. This prospective single-arm clinical trial was conducted between July 26, 2001, and November 30, 2001. Patients underwent a baseline week and then 4 weeks of gabapentin treatment, with increasing doses during the first 3 weeks, from 300 to 600 to 900 mg/d. Data were obtained primarily from patient-completed questionnaires. Data from 20 evaluable women (of 24 entered in the trial) were available. Four patients discontinued use of gabapentin for perceived drug-related untoward symptoms, primarily related to light-headedness and dizziness. The 16 patients who completed this clinical trial had a mean reduction in hot flash frequency, in the fourth treatment week compared to the baseline week, of 66%. Their corresponding hot flash score (frequency times average severity) reduction was 70%. Additionally, patients who completed the 4 treatment weeks had a strong tendency to report an improvement in several other symptoms. Although a double-blind placebo-controlled clinical trial should be conducted to better elucidate the efficacy and toxicity of gabapentin in patients with hot flashes, the available data suggest that gabapentin is a reasonable treatment to consider in patients with hot flashes if they do not wish to use hormonal therapy.

Gabapentin for Relief of Neuropathic Pain Related to Anticancer Treatment: A Preliminary Study

The aim of our study was to explore a potential analgesic effect of gabapentin in patients with neuropathic pain caused by anticancer treatment. A total of 23 outpatients without active disease and with chronic, treatment-related pain were included in this single-center, open-label, exploratory, non-controlled study. The primary end-points were pain intensity and pain relief following a 4-week treatment period. A total of 15 patients (65%) completed the study, 5 (22%) discontinued the study due to treatment failure and 3 (13%) due to toxicity. More than 50% reduction in pain intensity was obtained in 11 of 23 patients (48%, 95% CI 30-66%). Pain relief increased from 8.33% (±13.64) to 66.58% (±18.35) (p <0.01). Somnolence, mental clouding, and headache were the most frequently reported adverse events. We concluded that gabapentin should be accepted for further investigation in this important setting of supportive care.

Adjunctive gabapentin in patients with intellectual disability and bipolar spectrum disorders.

The aim of the present study was to assess the efficacy of adjunctive gabapentin (GBP) in the treatment of patients with intellectual disability (ID) and bipolar spectrum disorders. Ten affected subjects with demonstrable increases in symptomatology during 'significant' life events which had interfered with or induced the interruption of their rehabilitation programmes were chosen for this study. The meaning of 'significant' was defined for each patient as a frequently repeated life event which had elicited a marked increase in symptoms on at least two occasions. Gabapentin (300-900 mg day-1) was added to the standard therapy. The subjects' psychopathological conditions during the significant life event were assessed by means of standardized tools both before and after adjunctive therapy with GBP. A positive response to therapy was observed, with subsequent improvement of psychopathological conditions, particularly for anxiety and depressive symptoms. The promising results obtained with GBP suggest the need for further trials. Adjunctive GBP may become an alternative treatment approach for patients with ID in whom traditional mood-stabilizing agents have frequent contraindications.