A study on the action of two calcium channel blockers (verapamil and flunarizine) upon an experimental model of tardive dyskinesia in rats.

Tardive dyskinesia (TD), a serious complications of neuroleptic chronic use, has no effective therapy yet. We performed an experiment to study the action on TD, of the calcium channel blockers (CCB) drugs, verapamil and flunarizine. We obtained the TD model in rats, administering haloperidol for a 21-day period. After this, the stereotyped movement induced by apomorphine was rated. The CCB drugs were administered in acute (in the 28th day) and chronic (for 8 days, after the 25th day) experiments. Acutely, verapamil increased the stereotyped behaviour, and promoted a reduction of it in the chronic experiment. The results suggest that CCB drugs should be tested in clinical trials of TD.