Chronic melperone administration does not enhance oral movements in rats.

Melperone and haloperidol were compared in a rat model for tardive dyskinesia. Drugs were given chronically for 12 months with the drinking water and the frequency of oral movements was measured at monthly intervals. Haloperidol (0.2 and 0.4 mg/kg/d) produced an increase in vacuous chewing movements, whereas melperone (2.4, 5.1 and 11.0 mg/kg/d) did not differ from untreated controls.