Gabapentin for the symptomatic treatment of painful neuropathy in patients with diabetes mellitus: a randomized controlled trial. Gabapentin in traumatic nerve injury pain: a randomized, double-blind, placebo-controlled, cross-over, multi-center study. Gabapentin in neuropathic pain syndromes: a randomised, double-blind, placebo-controlled trial. Gabapentin for neuropathic cancer pain: a randomized controlled trial from the Gabapentin Cancer Pain Study Group. Gabapentin in the treatment of neuropathic pain after spinal cord injury: a prospective, randomized, double-blind, crossover trial. Gabapentin for the treatment of postherpetic neuralgia: a randomized controlled trial. Morphine, gabapentin, or their combination for neuropathic pain. Gabapentin is a first line drug for the treatment of neuropathic pain in spinal cord injury. Efficient assessment of neuropathic pain drugs in patients with small fiber sensory neuropathies. Efficacy of gabapentin in treating chronic phantom limb and residual limb pain. Comparison of the effectiveness of amitriptyline and gabapentin on chronic neuropathic pain in persons with spinal cord injury. Efficacy of gabapentin in the management of chemotherapy-induced peripheral neuropathy: a phase 3 randomized, double-blind, placebo-controlled, crossover trial (N00C3). Randomized double-blind study comparing the efficacy of gabapentin with amitriptyline on diabetic peripheral neuropathy pain. Efficacy and tolerability of gastric-retentive gabapentin for the treatment of postherpetic neuralgia: results of a double-blind, randomized, placebo-controlled clinical trial. Gabapentin extended-release tablets for the treatment of patients with postherpetic neuralgia: a randomized, double-blind, placebo-controlled, multicentre study. Gabapentin in the treatment of fibromyalgia: a randomized, double-blind, placebo-controlled, multicenter trial. Gabapentin extended release for the treatment of painful diabetic peripheral neuropathy: efficacy and tolerability in a double-blind, randomized, controlled clinical trial. Gabapentin in postherpetic neuralgia: a randomised, double blind, placebo controlled study. Gabapentin vs. amitriptyline in painful diabetic neuropathy: an open-label pilot study. Gabapentin and venlafaxine for the treatment of painful diabetic neuropathy. Double-blind, placebo-controlled trial of lamotrigine in combination with other medications for neuropathic pain. A placebo-controlled trial of gabapentin for painful HIV-associated sensory neuropathies. Nortriptyline and gabapentin, alone and in combination for neuropathic pain: a double-blind, randomised controlled crossover trial. Prolonged-release oxycodone enhances the effects of existing gabapentin therapy in painful diabetic neuropathy patients. Gabapentin in postamputation phantom limb pain: a randomized, double-blind, placebo-controlled, cross-over study. Gabapentin (Neurontin) as add-on therapy in patients with partial seizures: a double-blind, placebo-controlled study. The International Gabapentin Study Group.
Pain is the most disturbing symptom of diabetic peripheral neuropathy. As many as 45% of patients with diabetes mellitus develop peripheral neuropathies.
                To evaluate the effect of gabapentin monotherapy on pain associated with diabetic peripheral neuropathy.
                Randomized, double-blind, placebo-controlled, 8-week trial conducted between July 1996 and March 1997.
                Outpatient clinics at 20 sites.
                The 165 patients enrolled had a 1- to 5-year history of pain attributed to diabetic neuropathy and a minimum 40-mm pain score on the Short-Form McGill Pain Questionnaire visual analogue scale.
                Gabapentin (titrated from 900 to 3600 mg/d or maximum tolerated dosage) or placebo.
                The primary efficacy measure was daily pain severity as measured on an 11-point Likert scale (0, no pain; 10, worst possible pain). Secondary measures included sleep interference scores, the Short-Form McGill Pain Questionnaire scores, Patient Global Impression of Change and Clinical Global Impression of Change, the Short Form-36 Quality of Life Questionnaire scores, and the Profile of Mood States results.
                Eighty-four patients received gabapentin and 70 (83%) completed the study; 81 received placebo and 65 (80%) completed the study. By intent-to-treat analysis, gabapentin-treated patients' mean daily pain score at the study end point (baseline, 6.4; end point, 3.9; n = 82) was significantly lower (P<.001) compared with the placebo-treated patients' end-point score (baseline, 6.5; end point, 5.1; n = 80). All secondary outcome measures of pain were significantly better in the gabapentin group than in the placebo group. Additional statistically significant differences favoring gabapentin treatment were observed in measures of quality of life (Short Form-36 Quality of Life Questionnaire and Profile of Mood States). Adverse events experienced significantly more frequently in the gabapentin group were dizziness (20 [24%] in the gabapentin group vs 4 [4.9%] in the control group; P<.001) and somnolence (19 [23%] in the gabapentin group vs 5 [6%] in the control group; P = .003). Confusion was also more frequent in the gabapentin group (7 [8%] vs 1 [1.2%]; P = .06).
                Gabapentin monotherapy appears to be efficacious for the treatment of pain and sleep interference associated with diabetic peripheral neuropathy and exhibits positive effects on mood and quality of life. A double-blind, randomized, placebo-controlled cross-over multi-center study was conducted to evaluate the efficacy and safety of gabapentin in the treatment of neuropathic pain caused by traumatic or postsurgical peripheral nerve injury, using doses up to 2400 mg/day. The study comprised a run-in period of two weeks, two treatment periods of five weeks separated by a three weeks' washout period. The primary efficacy variable was the change in the mean pain intensity score from baseline to the last week of treatment. Other variables included pain relief, health related quality of life (SF-36), interference of sleep by pain, Clinician and Patient Global Impression of Change, and adverse effects. Nine centers randomized a total of 120 patients, 22 of whom withdrew. There was no statistically significant difference between the treatments for the primary outcome efficacy variable. However, gabapentin provided significantly better pain relief (p=0.015) compared with placebo. More patients had at least a 30% pain reduction with gabapentin compared with placebo (p=0.040) and pain interfered significantly less with sleep during gabapentin treatment compared with placebo (p=0.0016). Both the Patient (p=0.023) and Clinician (p=0.037) Global Impression of Change indicated a better response with gabapentin compared with placebo. Gabapentin was well tolerated. The most common adverse effects were dizziness and tiredness. A double-blind, randomised, placebo-controlled 8-week study was conducted to evaluate the efficacy and safety of gabapentin in the treatment of neuropathic pain, using doses up to 2400 mg/day. The study used a novel design that was symptom- rather than syndrome-based; an approach that aimed to reflect the realities of clinical practice. Participants had a wide range of neuropathic pain syndromes, with at least two of the following symptoms: allodynia, burning pain, shooting pain, or hyperalgesia. Patients were randomised to gabapentin (n=153) or placebo (n=152). Gabapentin was given in three divided doses, initially titrated to 900 mg/day over 3 days, followed by two further increases, to a maximum of 2400 mg/day if required by the end of week 5. The primary outcome measure was changed in average daily pain diary score (baseline versus final week). Over the 8 week study, this score decreased (i.e. improved) by 1.5 (21%) in gabapentin treated patients and by 1.0 (14%) in placebo treated patients (P=0.048, rank-based analysis of covariance). Significant differences were shown in favour of gabapentin (P<0.05) for the Clinician and Patient Global Impression of Change, and some domains of the Short Form-McGill Pain Questionnaire. Improvements were also shown in patient-reported outcomes in quality of life, as seen by significant differences in favour of gabapentin in several domains of the Short-Form-36 Health Survey. Gabapentin was well tolerated and the majority of patients completed the study (79 versus 73% for placebo). The most common adverse events were mild to moderate dizziness and somnolence, most of which were transient and occurred during the titration phase. This study shows that gabapentin reduces pain and improves some quality-of-life measures in patients with a wide range of neuropathic pain syndromes. To determine the analgesic effect of the addition of gabapentin to opioids in the management of neuropathic cancer pain.
                One hundred twenty-one consecutive patients with neuropathic pain due to cancer, partially controlled with systemic opioids, participated in a multicenter, randomized, double-blind, placebo-controlled, parallel-design, 10-day trial from August 1999 to May 2002. Gabapentin was titrated from 600 mg/d to 1,800 mg/d in addition to stable opioid dose. Extra opioid doses were available as needed. Zero to 10 numerical scale was used to rate average daily pain. The average pain score over the whole follow-up period was used as main outcome measure. Secondary outcome measures were: intensity of burning pain, shooting/lancinating pain, dysesthesias (also scored on 0 to 10 numerical scale), number of daily episodes of lancinating pain, presence of allodynia, and daily extra doses of opioid analgesics.
                Overall, 79 patients received gabapentin and 58 (73%) completed the study; 41 patients received placebo and 31 (76%) completed the study. Analysis of covariance (ANCOVA) on the intent-to-treat population showed a significant difference of average pain intensity between gabapentin (pain score, 4.6) and placebo group (pain score, 5.4; P =.0250). Among secondary outcome measures, dysesthesia score showed a statistically significant difference (P =.0077; ANCOVA on modified intent-to-treat population = 115 patients with at least 3 days of pain assessments). Reasons for withdrawing patients from the trial were adverse events in six patients (7.6%) receiving gabapentin and in three patients receiving placebo (7.3%).
                Gabapentin is effective in improving analgesia in patients with neuropathic cancer pain already treated with opioids. Neuropathic pain is a common complaint after traumatic spinal cord injury (SCI). Gabapentin, a synthetic structural analogue of GABA, has been shown to have beneficial effects in the treatment of neuropathic pain in other diagnostic groups; however, no standardized clinical trial has been performed to evaluate its efficacy after SCI.
                A 10-week, prospective, randomized, double-blind, crossover, and placebo-controlled clinical trial.
                To determine the efficacy of gabapentin in the treatment of SCI-related neuropathic pain.
                Seven subjects with neuropathic pain, who were more than 30 days post-SCI, completed the study. Two groups received a 4-week course of gabapentin and placebo in a randomized crossover design with a 2-week washout period. The Neuropathic Pain Scale was used to record daily pain levels. Data were analyzed using the Wilcoxon signed rank test.
                Gabapentin has some beneficial effects on certain types of neuropathic pain. There was a significant decrease of "unpleasant feeling" and a trend toward a decrease in both the "pain intensity" and "burning sensation" at the fourth week of gabapentin treatment compared with those on the placebo. No significant difference was found among other pain descriptors during the gabapentin and placebo treatment, although this may have been limited by the small sample size and low maximum dosage of gabapentin.
                Gabapentin reduces certain types of neuropathic pain in the SCI population. Future studies with larger sample sizes, higher dosages, and quicker titration will help further determine the efficacy of gabapentin in the treatment of SCI-related neuropathic pain. Postherpetic neuralgia (PHN) is a syndrome of often intractable neuropathic pain following herpes zoster (shingles) that eludes effective treatment in many patients.
                To determine the efficacy and safety of the anticonvulsant drug gabapentin in reducing PHN pain.
                Multicenter, randomized, double-blind, placebo-controlled, parallel design, 8-week trial conducted from August 1996 through July 1997.
                Sixteen US outpatient clinical centers.
                A total of 229 subjects were randomized.
                A 4-week titration period to a maximum dosage of 3600 mg/d of gabapentin or matching placebo. Treatment was maintained for another 4 weeks at the maximum tolerated dose. Concomitant tricyclic antidepressants and/or narcotics were continued if therapy was stabilized prior to study entry and remained constant throughout the study.
                The primary efficacy measure was change in the average daily pain score based on an 11-point Likert scale (0, no pain; 10, worst possible pain) from baseline week to the final week of therapy. Secondary measures included average daily sleep scores, Short-Form McGill Pain Questionnaire (SF-MPQ), Subject Global Impression of Change and investigator-rated Clinical Global Impression of Change, Short Form-36 (SF-36) Quality of Life Questionnaire, and Profile of Mood States (POMS). Safety measures included the frequency and severity of adverse events.
                One hundred thirteen patients received gabapentin, and 89 (78.8%) completed the study; 116 received placebo, and 95 (81.9%) completed the study. By intent-to-treat analysis, subjects receiving gabapentin had a statistically significant reduction in average daily pain score from 6.3 to 4.2 points compared with a change from 6.5 to 6.0 points in subjects randomized to receive placebo (P<.001). Secondary measures of pain as well as changes in pain and sleep interference showed improvement with gabapentin (P<.001). Many measures within the SF-36 and POMS also significantly favored gabapentin (P< or =.01). Somnolence, dizziness, ataxia, peripheral edema, and infection were all more frequent in the gabapentin group, but withdrawals were comparable in the 2 groups (15 [13.3%] in the gabapentin group vs 11 [9.5%] in the placebo group).
                Gabapentin is effective in the treatment of pain and sleep interference associated with PHN. Mood and quality of life also improve with gabapentin therapy. The available drugs to treat neuropathic pain have incomplete efficacy and dose-limiting adverse effects. We compared the efficacy of a combination of gabapentin and morphine with that of each as a single agent in patients with painful diabetic neuropathy or postherpetic neuralgia.
                In this randomized, double-blind, active placebo-controlled, four-period crossover trial, patients received daily active placebo (lorazepam), sustained-release morphine, gabapentin, and a combination of gabapentin and morphine--each given orally for five weeks. The primary outcome measure was mean daily pain intensity in patients receiving a maximal tolerated dose; secondary outcomes included pain (rated according to the Short-Form McGill Pain Questionnaire), adverse effects, maximal tolerated doses, mood, and quality of life.
                Of 57 patients who underwent randomization (35 with diabetic neuropathy and 22 with postherpetic neuralgia), 41 completed the trial. Mean daily pain (on a scale from 0 to 10, with higher numbers indicating more severe pain) at a maximal tolerated dose of the study drug was as follows: 5.72 at baseline, 4.49 with placebo, 4.15 with gabapentin, 3.70 with morphine, and 3.06 with the gabapentin-morphine combination (P<0.05 for the combination vs. placebo, gabapentin, and morphine). Total scores on the Short-Form McGill Pain Questionnaire (on a scale from 0 to 45, with higher numbers indicating more severe pain) at a maximal tolerated dose were 14.4 with placebo, 10.7 with gabapentin, 10.7 with morphine, and 7.5 with the gabapentin-morphine combination (P<0.05 for the combination vs. placebo, gabapentin, and morphine). The maximal tolerated doses of morphine and gabapentin were lower (P<0.05) with the combination than for each drug as single agent. At the maximal tolerated dose, the gabapentin-morphine combination resulted in a higher frequency of constipation than gabapentin alone (P<0.05) and a higher frequency of dry mouth than morphine alone (P<0.05).
                Gabapentin and morphine combined achieved better analgesia at lower doses of each drug than either as a single agent, with constipation, sedation, and dry mouth as the most frequent adverse effects.
                Copyright 2005 Massachusetts Medical Society. Prospective, randomized, double blind, placebo-controlled, crossover clinical trial.
                To determine the efficacy of gabapentin in the treatment of neuropathic pain related to spinal cord injury.
                Neuropathic pain is initiated or caused by a primary lesion or dysfunction in the nervous system. Neuropathic pain associated with spinal cord injury is quite refractory, and current treatments are not effective. Gabapentin, an anticonvulsant, has become the first choice in the treatment of neuropathic pain. The place of gabapentin in the treatment of spinal cord injury-related neuropathic pain was questioned in only a few recent reports; however, they are retrospectively designed, nonstandardized, and uncontrolled studies, or involve a very small series of patients using less than optimum doses.
                A total of 18-week study period included a 4-week medication/placebo titration period. This was followed by a 4-week stable dosing period when the patients continued to receive maximum tolerated doses, a 2-week washout period, then a crossover of 4 weeks of medication/placebo titration, and another 4 weeks of stable dosing period. Twenty paraplegic patients (female/male: 7/13) with complete spinal cord injury at the thoracic and lumbar level, aged between 20 and 65 years, with neuropathic pain for more than 6 months were recruited for the study.
                All patients completed the study. Gabapentin reduced the intensity as well as the frequency of pain, relieved all neuropathic pain descriptors except the itchy, sensitive, dull, and cold types, and improved the quality of life (P < 0.05).
                Gabapentin can be added to the list of first-line medications for the treatment of chronic neuropathic pain in spinal cord injury patients. It is a promising new agent and offers advantages over currently available treatments. We sought to develop an enrichment crossover study design that would allow us to efficiently evaluate and compare promising candidate neuropathic pain drugs. We evaluated the efficacy of gabapentin or tramadol vs. active placebo (diphenhydramine) in subjects with biopsy-proven painful idiopathic small fiber neuropathy (SFN) who were self-reported gabapentin responders. Eligible subjects entered two single blind run-in phases. In the first phase (Period A), subjects were treated with single blinded gabapentin at their prestudy dose followed by a second run-in phase (Period B) in which they were treated with diphenhydramine active placebo. Subjects with >or=3 pain and a >or=30% increase in pain intensity in Period B compared to Period A were then randomized to a double-blind three period cross over trial of gabapentin at pre study dosage, tramadol 50mg QID and diphenhydramine 50mgqhs. Of the 59 subjects enrolled, 41 subjects were excluded: Twenty-three had an insufficient rise in pain intensity in Period B; eight had skin biopsies that did not confirm SFN. Eighteen subjects were randomized into the double-blind, crossover phase. There was a significant treatment effect of gabapentin vs. diphenhydramine (p=0.001) and tramadol vs. diphenhydramine (p=0.018) by the before-bed daily pain score averaged over the final 7 days of each treatment period. We conclude that gabapentin and tramadol were effective in the treatment of painful SFN and that this experimental enrichment paradigm is attractive to screen potential neuropathic pain compounds for efficacy in proof-of-concept studies. Twenty-four adults with phantom limb pain (PLP) and/or residual limb pain (RLP) participated in a double-blind crossover trial. Participants were randomly assigned to receive gabapentin or placebo and later crossed over to the other treatment, with a 5-week washout interval in which they did not receive medication. Gabapentin was titrated from 300 mg to the maximum dose of 3,600 mg. Measures of pain intensity, pain interference, depression, life satisfaction, and functioning were collected throughout the study. Analyses revealed no significant group differences in pre- to posttreatment change scores on any of the outcome measures. More than half of the participants reported a meaningful decrease in pain during the gabapentin phase compared with about one-fifth who reported a meaningful decrease in pain during the placebo phase. In this trial, gabapentin did not substantially affect pain. More research on the efficacy of gabapentin to treat chronic PLP and RLP is needed. To test the hypotheses that both amitriptyline and gabapentin are more effective in relieving neuropathic pain than an active placebo, diphenhydramine.
                Randomized, controlled, double blind, triple crossover 8-week trial.
                Veterans Affairs medical center.
                Community dwelling adults with spinal cord injury (N=38) were recruited by telephone, letters, and flyers.
                Eight-week trial each of amitriptyline, gabapentin, and diphenhydramine.
                Pain intensity measured with a 10-cm visual analog scale (VAS) and an 11-point (0-10) numeric rating scale (NRS) and depressive symptomatology measured with the Center for Epidemiologic Studies Depression Scale-Short Form (CESD-SF).
                Baseline VAS scores for participants with low (< 10) CESD-SF scores was 4.61 and for those with high scores (> or = 10) it was 7.41. At week 8, in participants with high baseline CESD-SF scores, amitriptyline (mean, 4.21) was more effective than diphenhydramine (mean, 6.67; P=.035), and there was a nonsignificant trend suggesting that amitriptyline may be more effective than gabapentin (mean, 6.68; P=.061). Gabapentin was no more effective than diphenhydramine (P=.97). There was no significant difference among the medications for those with lower CESD-SF scores. Results could not be attributed to dropout rates, order or dose of medications, amount of medication taken for breakthrough pain, or side effects.
                Amitriptyline is more efficacious in relieving neuropathic pain than diphenhydramine at or below the level of spinal cord injury in people who have considerable depressive symptomatology. The antiepileptic agent, gabapentin, has been demonstrated to relieve symptoms of peripheral neuropathy due to various etiologies. On the basis of these data, a multicenter, double-blind, placebo-controlled, crossover, randomized trial was conducted to evaluate the effect of gabapentin on symptoms of chemotherapy-induced peripheral neuropathy (CIPN).
                Patients with symptomatic CIPN who complained of 'average' daily pain scores of either 1) >/=4 on a 0-10 numerical rating scale (NRS); or 2) >/=1 on the 0-3 Eastern Cooperative Oncology Group neuropathy scale (ENS) were eligible (higher numbers indicate greater severity of symptoms in both scales). Patients were randomized to receive gabapentin (target dose, 2700 mg) or placebo for 6 weeks. Crossover occurred after a 2-week washout period. CIPN-related symptoms were evaluated weekly by questionnaires. Statistical methods followed established methods for crossover designs, including Student t tests to compare average intrapatient differences between treatments and linear models to adjust for potential concomitant covariates.
                There were 115 patients who were randomly assigned to the treatment or control arm. Both groups were well matched by symptoms at study entry. Changes in symptom severity were statistically similar between the 2 groups during the study. Adverse events were mild and similar in both groups.
                This trial failed to demonstrate any benefit to using gabapentin to treat symptoms caused by CIPN. 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.
                To determine the efficacy of gabapentin compared with amitriptyline in treating diabetic peripheral neuropathy pain.
                Prospective, randomized, double-blind, double-dummy, crossover study.
                Veterans Affairs San Diego Healthcare System, Ambulatory Care Clinic.
                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.
                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.
                Pain relief measured by pain scale with verbal descriptors and global pain score assessment at treatment end.
                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).
                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. To determine the efficacy and safety of a gastric-retentive, extended-release gabapentin (gabapentin ER) taken once or twice daily for treatment of postherpetic neuralgia.
                Using an enrichment design, a randomized, double-blind, placebo-controlled study was conducted in 158 patients who had experienced pain for at least 3 months after healing of acute herpes zoster skin rash and who had a baseline average daily pain (ADP) score of > or =4 on a 0 to 10 Numerical Rating Scale. Patients received gabapentin ER either once daily (1800 mg PM) or twice daily (600 mg AM, 1200 mg PM) or placebo for 4 weeks. Efficacy measures included changes from baseline to end point in ADP score and average daily sleep interference score.
                Mean (SEM) changes for ADP score were -1.93 (0.28), -2.24 (0.29), and -1.29 (0.29) in the gabapentin ER once daily, twice daily, and placebo groups, respectively (P=0.089 and 0.014 for gabapentin ER once daily and twice daily, respectively, vs. placebo), with 25.5%, 28.8%, and 11.8% of patients, respectively, reporting > or =50% decrease from baseline in ADP score. Mean (SEM) changes in sleep interference scores were -1.94 (0.30), -2.28 (0.30), and -1.16 (0.30), respectively (P=0.048 and 0.006 for gabapentin ER once daily and twice daily, respectively, vs. placebo). Common adverse events in the gabapentin ER once daily, twice daily, and placebo groups, respectively, were dizziness (22.2%, 11.3%, and 9.8%) and somnolence (9.3%, 7.5%, and 7.8%).
                Gabapentin ER administered twice daily is effective and safe for the treatment of pain associated with postherpetic neuralgia. Postherpetic neuralgia (PHN) is a neuropathic pain syndrome that may develop subsequent to healing of herpes zoster rash.
                This study aimed to determine the efficacy and safety of gabapentin extended-release (gabapentin ER) tablets for the treatment of patients with PHN and to determine whether optimal benefits might be achieved with once-daily (QD) or divided-dose (DD) administration.
                This was a 10-week, randomized, double-blind, placebo-controlled, multicentre trial comparing gabapentin ER (total daily dose 1800 mg) either QD or as an asymmetrical DD with placebo in 407 patients with post-zoster pain for >or=3 months and a baseline average daily pain score (ADP)>or=4 on a 0-10 Likert numerical rating scale. The primary efficacy outcome was the ADP score mean change from baseline to week 10 using baseline observation carried forward (BOCF). Secondary efficacy outcomes included changes to week 10 in last observation carried forward (LOCF) ADP score, LOCF average daily sleep interference score, Short-Form McGill Pain Questionnaire score, Neuropathic Pain Scale score, and Brief Pain Inventory score.
                Of 407 randomized patients, 400 were included in the intent-to-treat population (gabapentin ER QD, n=134; gabapentin ER DD, n=135; placebo, n=131). Between-group differences in the least squares (LS) mean changes in BOCF ADP scores did not reach statistical significance (gabapentin ER QD -1.85 [p=0.110 vs placebo]; gabapentin ER DD -1.72 [p=0.255 vs placebo]; placebo -1.42). In the LOCF analysis, the LS mean ADP score for the gabapentin ER QD group, but not for the DD group, improved compared with placebo (gabapentin ER QD, -2.28; p=0.032 vs placebo). Improvements compared with placebo were also observed in the gabapentin ER QD group, but not for the DD group, for mean daily sleep interference scores (gabapentin ER QD, -2.49; placebo, -1.63; p<0.001). Most adverse events (AEs) were mild or moderate. Among gabapentin-treated patients, 12% and 11% withdrew due to AEs, most commonly for dizziness (2% and 3%), in the gabapentin ER QD and DD groups, respectively. Treatment-related AEs in the gabapentin ER-treated groups occurred in 31% of patients. The most common AEs in the gabapentin ER QD and DD groups included dizziness (10% and 15%), headache (4% and 7%), somnolence (3% and 7%) and peripheral oedema (5% and 5%), respectively.
                The primary efficacy endpoint for this study of gabapentin ER was not met, most likely due to the unexpectedly large placebo response. Outcomes on secondary endpoints suggest the potential efficacy of gabapentin ER QD. Gabapentin ER was well tolerated in this study. [Clinicaltrials.gov identifier NCT00335933]. 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. nan A multicentre double blind, randomised, placebo controlled 7-week study evaluated the efficacy and safety of gabapentin 1800 or 2400 mg/day in treating postherpetic neuralgia. Three hundred and thirty-four men and women aged at least 18 years (mean 73) received gabapentin 1800 or 2400 mg daily or placebo in three divided doses with a forced titration schedule. The primary outcome measure was change in average daily pain diary score (baseline week v final week). Secondary outcomes included mean weekly sleep interference score; Short Form-McGill Pain Questionnaire (SF-MPQ); Clinician and Patient Global Impression of Change (CGIC/PGIC); Short Form-36 Health Survey (SF-36). From week 1, pain scores showed a significantly greater improvement with gabapentin: the final difference v baseline was -34.5% for the 1800 mg dose, -34.4% for the 2400 mg dose compared with -15.7% for the placebo group. The difference vs. placebo was 18.8% for the 1800 mg dose (95% confidence interval 10.9-26.8%; P<0.01) and 18.7% for the 2400 mg dose (10.7-26.7%; P<0.01). Sleep interference diaries showed a similar pattern. There were significant differences in favour of gabapentin for number of patients reporting >50% reduction in their pain intensity, in the CGIC and PGIC, in the sensory and total scores of the SF-MPQ (both doses), in the visual analogue scale of pain of the SF-MPQ (2400 mg only) and in the vitality, bodily pain and mental health domains of the SF-36. Overall gabapentin was well tolerated. The most common adverse events were dizziness and somnolence, particularly during the titration phase. Thus, this study confirms the role of gabapentin as an efficacious and well-tolerated treatment for postherpetic neuralgia. The objective of this study was to compare the efficacy and tolerability of gabapentin and amitriptyline monotherapy in painful diabetic neuropathy. This was a 12-week, open-label, prospective, randomized trial. Twenty-five type-II diabetic patients with pain attributed to diabetic neuropathy and a minimum score of 2 on a pain intensity scale ranging from 0 (no pain) to 4 (excruciating pain) were randomized to receive either gabapentin, titrated from 1,200 mg/day to a maximum of 2,400 mg/day, or amitriptyline, titrated from 30 mg/day to a maximum of 90 mg/day. Both drugs were titrated over a 4-week period and maintained at the maximum tolerated dose for 8 weeks. The main outcome measures were weekly pain intensity and paresthesia intensity, measured on two categorical scales. Thirteen patients received gabapentin and 12 received amitriptyline. All 25 patients completed the trial. Gabapentin produced greater pain reductions than amitriptyline (mean final scores were 1.9 vs. 1.3 points below baseline scores; P = 0.026). Decreases in paresthesia scores also were in favor of gabapentin (1.8 vs. 0.9 points; P = 0. 004). Adverse events were more frequent in the amitriptyline group than in the gabapentin group: they were reported by 11/12 (92%) and 4/13 (31%) of patients, respectively (P = 0.003). Side effects were the main limiting factor preventing dose escalation. Gabapentin produced greater improvements than amitriptyline in pain and paresthesia associated with diabetic neuropathy. Additionally, gabapentin was better tolerated than amitriptyline. Further controlled trials are needed to confirm these preliminary results. To evaluate the safety and efficacy of gabapentin and venlafaxine in the treatment of painful diabetic neuropathy in patients whose pain did not improve with gabapentin monotherapy.
                (1) A randomized, double-blind, placebo-controlled, 8-week clinical trial comparing gabapentin versus placebo to define a patient population whose pain did not improve with monotherapy; (2) a second 8-week trial comparing gabapentin plus venlafaxine with gabapentin plus placebo; (3) a third uncontrolled 8-week trial of patients who did not improve on gabapentin monotherapy and then received venlafaxine in addition to gabapentin.
                (1) Gabapentin-treated patients showed statistically significant improvement in pain reduction as well as improvement in quality of life and mood disturbance when compared with placebo-treated patients; (2) patients who received gabapentin plus venlafaxine showed significant improvement in pain reduction, mood disturbance, and quality of life when compared with patients treated with gabapentin plus placebo; (3) patients who received gabapentin plus venlafaxine showed significant improvement in pain reduction, mood disturbance, and quality of life.
                (1) Gabapentin is efficacious in the treatment of painful diabetic neuropathy; (2) and (3) in patients who do not respond to gabapentin monotherapy, the addition of venlafaxine is also efficacious. This randomized, double-blind, placebo-controlled study was undertaken to evaluate the efficacy and tolerability of lamotrigine added to gabapentin, a tricyclic antidepressant, or a nonopioid analgesic in patients whose neuropathic pain was inadequately controlled with these medications. Patients with neuropathic pain from diabetic peripheral neuropathy, postherpetic neuralgia, traumatic/surgical nerve injury, incomplete spinal cord injury, trigeminal neuralgia, multiple sclerosis, or HIV-associated peripheral neuropathy, who had a mean weekly pain score > or =4 on an 11-point numerical rating scale, were randomized to receive a flexible dose of lamotrigine 200, 300, or 400mg daily (n=111) or placebo (n=109) for up to 14 weeks (including eight weeks of dose escalation) in addition to their prestudy regimen of gabapentin, a tricyclic antidepressant, or a nonopioid analgesic. No statistically significant difference in the mean change in pain-intensity score from baseline to Week 14 (primary endpoint) was detected between lamotrigine and placebo (P=0.67). Differences between lamotrigine and placebo were not statistically significant for secondary efficacy assessments, including mean changes from baseline in the Short-Form McGill Pain Questionnaire, the Neuropathic Pain Scale, rescue medication use, and the percentages of patients rated as much improved or very much improved at the end of treatment on the Clinician Global Impression of Change scale and the Patient Global Impression of Change scale. Lamotrigine was generally well tolerated. Lamotrigine (up to 400 mg/day) added to gabapentin, a tricyclic antidepressant, or a nonopioid analgesic did not demonstrate efficacy as an adjunctive treatment of neuropathic pain but was generally safe and well tolerated. Painful HIV-associated sensory neuropathies (HIV-SN) are a common complication of HIV infection. The pathogenesis is unknown and the treatment very limited. Gabapentin (GBP) is effective in painful diabetic neuropathy and postherpetic neuralgia and its effectiveness on painful HIV-SN has been reported anecdotally.
                Multicenter, prospective, randomised, double-blind, placebo-controlled study.
                Patients were followed for a 1-week screening, a 4-week double-blind and a 2-week open treatment phase. GBP was initiated at 400 mg/d, titrated over 2 weeks to 1200 mg/d, and then either maintained at this level or-if not beneficial-titrated to 2400 mg/d. After 4 weeks the medication was unblinded and the patient had the choice to begin, to maintain or to increase GBP to 3600 mg/d. The primary outcome measure was an improvement in median pain on the Visual Analogue Scale (VAS) from the screening week compared to the 4(th) treatment week. A secondary efficacy measure was the median sleep score (VAS).
                15 patients received GBP and 11 placebo. In each group one patient dropped out during the doubleblind phase. Median pain (GBP 5.1; placebo 4.7) and sleep score (GBP 4.5; placebo 5.6) did not differ between both groups at baseline. In the GBP-group there was a significant decrease of the pain to 2.85 (-44.1 %) as well as of the sleep VAS to 2.3 (-48.9 %). No significant decrease in the pain (median VAS=3.3, -29.8 %) as well as in the sleep score (median VAS=4.95, -11.6 %) was observed in the placebo-group. GBP was generally well tolerated. The most frequent side effect was somnolence reported in 80% of GBP-treated patients.
                GBP was more effective than placebo in reducing pain and sleep interference in patients with HIV-SN. Drugs for neuropathic pain have incomplete efficacy and dose-limiting side-effects when given as monotherapy. We assessed the efficacy and tolerability of combined nortriptyline and gabapentin compared with each drug given alone.
                In this double-blind, double-dummy, crossover trial, patients with diabetic polyneuropathy or postherpetic neuralgia, and who had a daily pain score of at least 4 (scale 0-10), were enrolled and treated at one study site in Canada between Nov 5, 2004, and Dec 13, 2007. 56 patients were randomised in a 1:1:1 ratio with a balanced Latin square design to receive one of three sequences of daily oral gabapentin, nortriptyline, and their combination. In sequence, a different drug was given to each randomised group in three treatment periods. During each 6-week treatment period, drug doses were titrated towards maximum tolerated dose. The primary outcome was mean daily pain at maximum tolerated dose. Analysis was by intention to treat. This trial is registered, number ISRCTN73178636.
                45 patients completed all three treatment periods; 47 patients completed at least two treatment periods and were analysed for the primary outcome. Mean daily pain (0-10; numerical rating scale) was 5.4 (95% CI 5.0 to 5.8) at baseline, and at maximum tolerated dose, pain was 3.2 (2.5 to 3.8) for gabapentin, 2.9 (2.4 to 3.4) for nortriptyline, and 2.3 (1.8 to 2.8) for combination treatment. Pain with combination treatment was significantly lower than with gabapentin (-0.9, 95% CI -1.4 to -0.3, p=0.001) or nortriptyline alone (-0.6, 95% CI -1.1 to -0.1, p=0.02). At maximum tolerated dose, the most common adverse event was dry mouth, which was significantly less frequent in patients on gabapentin than on nortriptyline (p<0.0001) or combination treatment (p<0.0001). No serious adverse events were recorded for any patients during the trial.
                Combined gabapentin and nortriptyline seems to be more efficacious than either drug given alone for neuropathic pain, therefore we recommend use of this combination in patients who show a partial response to either drug given alone and seek additional pain relief. Future trials should compare other combinations to their respective monotherapies for treatment of such pain.
                Canadian Institutes of Health Research. Neuropathic pain remains one of the most challenging pain syndromes; under-diagnosed, poorly managed and associated with significant co-morbidity. With standard therapeutic treatments, responders rarely exceed 50% pain relief and the majority suffer from residual pain. Titration to optimum dose is often limited by dose-related adverse events.
                This randomized, double-blind, placebo-controlled study assessed the potential benefit of adding oxycodone (OxyContin tablets) to gabapentin. The primary endpoint was to evaluate the analgesic efficacy of co-administration of gabapentin and prolonged-release oxycodone, whilst also evaluating the use of escape medication, sleep quality and global assessment of pain.
                Three hundred and thirty eight patients with moderate to severe painful diabetic neuropathy despite receiving their maximum tolerated dose of gabapentin, had oral prolonged-release oxycodone or placebo tablets added to their therapy for up to 12 weeks.
                Oxycodone-gabapentin reduced pain score by 33% from baseline to end of treatment. The overall treatment effect was greater with oxycodone-gabapentin than with placebo-gabapentin (P = 0.007). Oxycodone-gabapentin also significantly improved pain relief vs gabapentin alone (P = 0.003). Oxycodone-gabapentin co-administration was associated with less escape medication use (P = 0.03) and fewer nights of disturbed sleep (P < 0.05). Discontinuations due to lack of therapeutic effect were much lower (14% vs 54%) with oxycodone-gabapentin. The commonly seen opiate-induced adverse events were not exacerbated by the combination of oxycodone and gabapentin.
                This study provides the first evidence that co-administration of prolonged-release oxycodone and existing gabapentin therapy has a clinically meaningful effect in painful diabetic neuropathy. Severe phantom limb pain after surgical amputation affects 50% to 67% of patients and is difficult to treat. Gabapentin is effective in several syndromes of neuropathic pain. Therefore, we evaluated its analgesic efficacy in phantom limb pain.
                Patients attending a multidisciplinary pain clinic with phantom limb pain were enrolled into this randomized, double-blind, placebo-controlled, cross-over study. Other anticonvulsant therapy was discontinued. Each treatment was 6 weeks separated by a 1-week washout period. Codeine/paracetamol was allowed as rescue analgesia. The daily dose of gabapentin was titrated in increments of 300 mg to 2400 mg or the maximum tolerated dose. Patients were assessed at weekly intervals. The primary outcome measure was visual analog scale (VAS) pain intensity difference (PID) compared with baseline at the end of each treatment. Secondary measures were indices of sleep interference, depression (Hospital Anxiety and Depression [HAD] scale), and activities of daily living (Bartel Index).
                Nineteen eligible patients (mean age, 56 years; range, 24 to 68 years; 16 men) were randomized, of whom 14 completed both arms of the study. Both placebo and gabapentin treatments resulted in reduced VAS scores compared with baseline. PID was significantly greater than placebo for gabapentin therapy at the end of the treatment (3.2 +/- 2.1 v 1.6 +/- 0.7, P =.03). There were no significant differences between placebo and gabapentin therapy in terms of the number of tablets of rescue medication required, sleep interference, HAD scale, or Bartel Index. The medication was well tolerated with few reports of adverse effects.
                After 6 weeks, gabapentin monotherapy was better than placebo in relieving postamputation phantom limb pain. There were no significant differences in mood, sleep interference, or activities of daily living, but a type II error cannot be excluded for these variables. A multicenter, double-blind, randomized, placebo-controlled study evaluated the efficacy and safety of gabapentin (Neurontin, GBP) as add-on therapy in 272 patients with refractory partial seizures who were receiving one to two standard antiepileptic drugs (AEDs). Efficacy assessments compared the frequency of partial seizures during the 12-week treatment phase (T) and the 12-week baseline period (B). The primary analysis compared data for patients receiving GBP 900 mg/day with placebo; the GBP 1,200-mg/day group provided dose-response data. Efficacy criteria were percentage of change in seizure frequency (PCH), responder rate (percentage of patients with > or = 50% reduction in seizure frequency), and response ratio, where RRatio = (T-B)/(T + B). Median PCH was -21.8% in the 900-mg/day group and -17.8% in the 1,200-mg/day group as compared with -0.3% in the placebo group. Responder rate was 22.9% in the 900-mg/day group and 10.1% in the placebo group (p = 0.020, Fisher's exact test). Adjusted mean RRatio was -0.136 in the 900-mg/day group and -0.025 in the placebo group (p = 0.0046, analysis of variance ANOVA). Results showed slightly greater improvement for the 1,200-mg/day than for the 900-mg/day group (RRatio = -0.157, responder rate 28.0%). Adverse events (AE) occurred in 69% of patients in the 900-mg/day group and in 64% in the 1,200-mg/day group as compared with 52% in patients receiving placebo as add-on therapy. The most frequent AE among patients treated with GBP were somnolence, dizziness, and fatigue. Clinical laboratory evaluations showed no clinically important trends and no evidence of hepatic or hematopoietic effects.(ABSTRACT TRUNCATED AT 250 WORDS)
Gabapentin provides pain relief of a high level in about a third of people who take if for painful neuropathic pain. Adverse events are frequent, but mostly tolerable. More conservative estimates of efficacy resulted from using better definitions of efficacy outcome at higher, clinically important, levels, combined with a considerable increase in the numbers of studies and participants available for analysis.