EFFICACY AND TOLERANCE OF LONG-TERM, HIGH-DOSE GABAPENTIN - ADDITIONAL OBSERVATIONS

Gabapentin (GBP) has shown antiepileptic efficacy and good tolerance i n clinical trials. Much remains to be learned about its clinical use. As a participating center in the US Gabapentin Study Group, we report observations that have practical implications for patient management. Twenty-three patients with intractable partial-onset seizures initiate d open-label treatment after a blinded placebo-controlled add-on dose efficacy study. In the titration phase, GBP and concurrent antiepilept ic drugs (AEDs) were adjusted to achieve optimal efficacy on maximally tolerated GBP doses. Nine patients had no significant improvement in seizure control and discontinued GBP. The remaining 14 patients were o bserved while treated long-term with stable-dose GBP and concurrent AE Ds. Improvement was maintained as long as patients were followed: less than or equal to 4 years. The protocol-allowed upper dose limit, 2,40 0 mg/day, was well tolerated by 16 of 23 patients, indicating that hig her doses may be tolerated. GBP discontinuation did net cause rebound increases in seizure frequency. The most common adverse events (AEs) ( in 14 of 23) were similar to those induced by concurrent AEDs and resp onded to reduction of concurrent AEDs. Many patients reported positive psychostimulatory effects. These observations extend previous finding s indicating that GBP is an effective and well-tolerated drug for trea tment of partial-onset seizures.