Clozapine for the control of hemiballismus.

Pharmacological agents used for the control of ballistic movements include chloral hydrate, barbiturates, paraldehyde, bromides, phenothiazines, progabide, haloperidol, pimozide, reserpine, tetrabenazine, sodium valproate, and dimethylaminoethanol. These agents are believed to act by different mechanisms, including modification of dopaminergic, GABAergic, or cholinergic mechanisms. We report a case where, after failure of haloperidol, phenobarbital, and pimozide, the hemiballistic movements were controlled with clozapine.