Over the past two decades, a number of small studies and case reports have suggested that calcium channel blockers (e.g. nifedipine, verapamil, diltiazem) may be beneficial in the treatment of neuroleptic-induced tardive dyskinesia (Suddath et al. Pharmacol Biochem Behav 1991; 39: 743-745; Duncan et al. J Clin Psychopharmacol 1990; 10: 414-416).