The results of three large, placebo-controlled, multicenter clinical trials of gabapentin as add-on therapy in patients with refractory partial seizures are summarized in a report from the Departments of Neurology and Psychiatry and the International Center for Epilepsy, University of Miami School of Medicine, and the Veterans Affairs Medical Center, Miami, FL. In a total of 705 patients (646 evaluable), mean age 33 years, treated the responder rate (RR) ranged from 17.6 to 28% in those receiving 600 to 1800 mg gabapentin daily; the median seizure frequency decreased by 17.8 to 31.9% in gabapentin-treated compared with 0.3 to 12.5% in placebo-control patients. Based on the RR (the percentage of patients with >50% decrease in seizure frequency), a dose-response effect was present for simple partial, complex partial, and secondarily generalized tonic-clonic seizures. Adverse effects, primarily mild to moderate in severity and transient, mainly affected the CNS and included somnolence (24%), dizziness (20%), and ataxia (17%). Skin rash in only 0.54% gabapentin-treated patients compared to an average 5 to 10% incidence with traditional AEDs. No significant changes in liver function were noted. [1]

COMMENT. Gabapentin is approved for patients >12 years of age with partial and secondarily generalized seizures. The role of gabapentin in the management of epilepsy is the subject of five papers in the above Neurology supplement. In addition to efficacy and safety addressed by Ramsay RE, the profile of desirable properties of a new AED are outlined by Mattson RH, the mechanism of action of gabapentin is reviewed by Taylor CP, and its lack of drug interaction and advantageous pharmacokinetics are stressed by McLean MJ. The absence of interactions between gabapentin and other AEDs and the rarity of serious adverse effects should encourage the expansion of clinical trials to include children younger than 12 years of age.