Long-term safety and efficacy of gabapentin (neurontin) as add-on therapy in patients with refractory partial seizures

Abstract In an international, multicenter, open-label study, the long-term efficacy and safety of gabapentin (GBP, Neurontin) as add-on therapy were investigated in 203 patients with partial seizures refractory to standard antiepileptic drugs (AEDs). All patients enrolled in this study had experienced improved seizure control with GBP in one of four previous, short-term studies. Patients received mean GBP dosages of 1,283 to 2,220 mg/day for periods of ⩽1,894 days (mean, 385 days). For purposes of efficacy analyses, data were divided into 12-week treatment periods. During long-term treatment, the efficacy of GBP was shown to be maintained by several primary efficacy measures. In all of the 12-week treatment periods, the percentage of change in seizure frequency from baseline was equal to or less than −24%, responder rate was >35%, and response ratio ranged between −0.2 and −0.338. Results for secondary efficacy measures also indicated that efficacy was maintained. The favorable safety profile of GBP also was maintained during long-term treatment. Our results suggest that GBP is an effective, safe, and well-tolerated add-on treatment for long-term use in patients with partial seizures refractory to standard AEDs.