Levetiracetam-induced parkinsonism in a Huntington disease patient.

The authors present a man with Huntington disease who was treated with levetiracetam (Keppra) in an effort to reduce chorea. Chorea was markedly reduced, but the patient developed parkinsonism and lethargy after 6 weeks of treatment. Symptoms consisted of resting tremor, rigidity, increased dystonia, and gait difficulty. Side effects from levetiracetam resolved completely within 7 days of levetiracetam discontinuation, and chorea returned to baseline.