Valproate-induced Parkinsonism in epilepsy patients.

We systematically examined 226 epilepsy patients in a tertiary-referral center and found 6 (5.04%) to have valproate-induced Parkinsonism. There was a significantly higher prevalence of patients with Parkinsonism in the group of patients treated with valproate compared to those who were on other antiepileptic drugs (6 [5.04%] of 119 vs. 0 [0%] of 107; chi2 = 5.54; P = 0.025). These six patients had been on valproate for more than 3 years (mean, 75.67 +/- 25.32 months) at an average dose of 750 +/- 273.86 mg/day. The valproate doses were decreased or discontinued with supplementation from another antiepileptic medication. The mean UPDRS motor score significantly improved from 10.67 +/- 5.1 to 4.75 +/- 2.75 (P < 0.05). There was no relapse of seizures. Clinicians working in tertiary-referral centers should have a high index of suspicion for valproate-induced Parkinsonism. Early recognition and switching into another antiepileptic medication may help reduce unnecessary suffering in these patients.