Masking of tardive dyskinesia with four times-a-day administration of chlorpromazine

Two chronic schizophrenic out-patients with tardive dyskinesia were treated with chlorpromazine in 2 regimens -- once-daily and four times-daily -- using a cross-over design. Two "blind" raters evaluated the severity of symptoms of tardive dyskinesia, pseudoparkinsonism and schizophrenia on rating scales every week during the 14-week-trial period. Results showed that the intensity of dyskinesia was significantly lower, and that of pseudoparkinsonism higher (but not significantly) with Q.I.D. than with O.D. medication. Symptoms of schizophrenia did not vary in severity appreciably with the two frequencies of drug intake. It is suggested that multiple-dose administration of a phenothiazine maintains a steady level of dopamine blockade throughout the day and thus masks the manifestations of tardive dyskinesia.