Gabapentin as add-on therapy in children with refractory partial seizures: a 12-week, multicentre, double-blind, placebo-controlled study. Gabapentin Paediatric Study Group. Gabapentin as add-on therapy in refractory partial epilepsy: a double-blind, placebo-controlled, parallel-group study. The US Gabapentin Study Group No. 5. Double-blind study of Gabapentin in the treatment of partial seizures. A randomized open-label study of gabapentin and lamotrigine in adults with learning disability and resistant epilepsy.
To evaluate the efficacy and safety of gabapentin (Neurontin; GBP) as add-on therapy for refractory partial seizures in paediatric patients aged 3-12 years.
                After a 6-week baseline period, 247 patients (54 centres) entered a 12-week double-blind phase and were randomized to receive either GBP (t.i.d., titrated to 23-35 mg/kg/ day) or placebo. Seizure activity and type were recorded daily. Efficacy variables included Response Ratio (RRatio), responder rate, and percentage change in frequency (PCH) for all partial seizures; PCH and RRatio for individual types of partial seizures; and investigator and parent/guardian global assessments of seizure frequency and patient well-being.
                RRatio for all partial seizures was significantly lower (better) for GBP-treated patients (p = 0.0407). Responder rate favored GBP, but the difference between treatment groups was not statistically significant. Median PCH for all partial seizures for the GBP treatment group (-17.0%) was better than that for the placebo group (-6.5%). Median PCH for specific seizure types showed GBP to be most effective in controlling complex partial seizures (-35%) and secondarily generalized seizures (-28%) when compared with placebo (-12%, +13%, respectively). A greater percentage of GBP-treated patients exhibited improvement according to investigator and parent/guardian global assessments, with a statistically significant difference observed in the parent/guardian global assessment of seizure-frequency reduction (p = 0.046). Three GBP patients and one placebo patient were seizure free during the double-blind treatment period. GBP was well tolerated.
                GBP was effective and well tolerated as an add-on therapy for partial seizures in paediatric patients with previously drug-resistant seizures. Gabapentin, administered as add-on therapy, was safe and effective in this 12-week, multicenter, placebo-controlled, parallel-group study in 306 patients with refractory partial epilepsy. For patients in each gabapentin treatment group (600, 1,200, or 1,800 mg/d), the mean response ratio was significantly better than that of a placebo group. The percentage of patients achieving at least a 50% reduction in seizure frequency was 8% among placebo-treated patients and ranged from 18% to 26% for patients who received gabapentin. Adverse events were generally mild and transient and occurred at a slightly higher frequency among patients receiving gabapentin than among those receiving placebo. Gabapentin did not affect the serum concentrations of concurrent antiepileptic drugs and was not regularly associated with any deviations in clinical laboratory values. Gabapentin's low inherent toxicity and its lack of drug interactions make it an ideal candidate for use as add-on therapy in patients with refractory partial epilepsy. Forty-three patients completed a double-blind, placebo-controlled study of Gabapentin (GBP) as add-on therapy in partial and secondarily generalized seizures. All patients were followed for an initial 3-month baseline period, after which they were randomly allocated to receive either a placebo or 900 or 1,200 mg/day GBP for 3 months. A statistically significant difference in seizure frequency from the baseline to the treatment phase was noted between patients receiving placebo and GBP 1,200 mg, in whom seizure frequency decreased 57%. The GBP dosage of 900 mg appeared to be ineffective. A close relationship was observed between the serum GBP concentrations and the GBP dosage based on the seizure frequency. Serum GBP concentrations greater than 2 micrograms/ml resulted in a lower frequency of seizures. The adverse effects were minor and consisted mainly of transient drowsiness. GBP appears to be effective in the treatment of partial epileptic seizures in a dosage-related manner. The aim of this study was to evaluate the efficacy and safety of gabapentin in patients with learning disabilities and resistant epilepsy, comparing the effects of gabapentin with lamotrigine on efficacy, behaviour and mood. An open-label, randomized, parallel group, multicentre add-on study comparing gabapentin with lamotrigine in 109 patients with drug-resistant localization-related epilepsy and learning disabilities was conducted: 39 patients were randomized to gabapentin and 44 to lamotrigine. The study population had a range of learning disabilities and severe partial epilepsy. The percentage of patients achieving a greater than or equal to 50% reduction in seizure frequency on gabapentin was 50%, (mean reduction in seizures was 51%). Compared to 48.6% of lamotrigine patients, no statistically significant treatment differences could be identified. The safety profile of both drugs was consistent with that seen in previous clinical trials. Carer-rated visual analogue scales detected significant improvements (P< 0.05) for the gabapentin-treated patients in seizure severity, attention, general health and sleeping pattern, while for lamotrigine seizure severity improved significantly. For learning disabled patients with resistant epilepsy, gabapentin and lamotrigine provide safe and effective treatment, with positive benefits on behaviour.
Gabapentin has efficacy as an add-on treatment in people with drug-resistant partial epilepsy. However, trials reviewed were of relatively short duration, and provide no evidence for the long-term efficacy of gabapentin. Results cannot be extrapolated to monotherapy or people with other epilepsy types.