• The frequency of extrapyramidal symptoms (EPS) attributed to chlorpromazine among 86 patients who received benztropine for the prevention of EPS (9.3%) was similar to that of the 568 patients who received chlorpromazine alone (10.6%). The data in this small sample indicated that the prophylactic use of benztropine had no effect in reducing the rate of EPS.
Swett C, Cole JO, Shapiro S, Slone D. Extrapyramidal Side Effects in Chlorpromazine RecipientsEmergence According to Benztropine Prophylaxis. Arch Gen Psychiatry. 1977;34(8):942-943. doi:10.1001/archpsyc.1977.01770200080009