Pregabalin add-on treatment in patients with partial seizures: A novel evaluation of flexible-dose and fixed-dose treatment in a double-blind, placebo-controlled study

Purpose: To evaluate pregabalin as add-on therapy for patients with partial seizures administered as fixed dose or as flexible dose adjusted to optimal seizure reduction and tolerability. Methods: Patients receiving antiepileptic drugs (98.8% between 1 and 3 AEDs; 1.2% on more than 3 AEDs) and experiencing >= 4 partial seizures during the 6-week baseline period and no 4-week seizure-free interval were randomized (1:2:2) to placebo (n = 73), pregabalin fixed dose (600 mg/day BID; n = 137), or pregabalin flexible dose (n = 131; 150 and 300 mg/day for 2 weeks each; 450 and 600 mg/day for 4 weeks each, BID) for 12 weeks. Dosage could be adjusted based on tolerability and maintained when a 4-week seizure-free period was achieved. Primary efficacy parameter was reduction in seizure frequency from baseline. Results: Both pregabalin regimens significantly reduced seizure frequency compared with placebo, by 35.4%, for flexible dose (p = 0.0091) and 49.3% for fixed dose (p = 0.0001) versus 10.6% for placebo, and the fixed-dose group was superior to the flexible-dose group (p = 0.0337). Most adverse events were mild or moderate. Discontinuation rates due to adverse events were 6.8% (placebo), 12.2% (pregabalin flexible dose), and 32.8% (pregabalin fixed dose). Patients receiving pregabalin fixed dose discontinued due to adverse event earlier than other groups. Conclusions: Pregabalin administered twice daily, either as fixed (600 mg/day), or as flexible (150-600 mg/day) dose, was highly effective and generally well-tolerated as add-on therapy for partial seizures with or without secondary generalization. Lower incidence of adverse events and discontinuations were achieved in patients receiving pregabalin when dosing was individualized to optimize efficacy and tolerability.