OBJECTIVE To determine whether pregabalin reduces SGTC seizures in clinically refractory epilepsy. METHODS METHODS Post hoc analysis performed on pooled data from three double-blind, placebo-controlled trials of similar design. METHODS Patients with partial seizures who failed > or =2 antiepileptic drugs at maximally tolerated doses. This analysis excluded those who did not have an SGTC seizure during baseline or treatment periods. METHODS Absolute and conditional reduction analyses examined change from baseline in SGTC seizure rates. The absolute reduction analysis used response ratio (RRatio) to compare reduction in seizure-frequency from baseline (B) during a 12-week treatment (T) period [RRatio=((T-B)/(T+B))x100]. The conditional analysis examined proportional risk of having SGTC seizure if a partial seizure had occurred. RESULTS Of 1052 intent-to-treat patients, 409 were included. Sixteen were seizure-free during treatment and not included in the conditional analysis. A significant reduction in absolute SGTC seizures from baseline was observed in patients receiving pregabalin 600 mg/day (treatment RRatio, -33 versus placebo, -3.7; P=0.0005). A lower dose of pregabalin (300mg/day), administered in one study, demonstrated a trend (nonsignificant) toward reduced SGTC seizures (treatment, -24.7 versus placebo, -10.0; P=0.2493). CONCLUSIONS As adjunctive therapy, pregabalin 600 mg/day is effective in reducing the absolute frequency of SGTC seizures in patients with refractory partial epilepsy, but not secondary generalization.