Enthusiastic acceptance of the more potent phenothiazines is still somewhat tempered by the relatively high incidence in phenothiazinetreated patients of what AYD describes as "a variety of disconcerting, occasionally alarming extrapyramidal reactions" (AYD, 1961). AYD reports that among 3,775 of his patients treated with phenothiazines, 38.9~ developed the following drug-induced extrapyramidal reactions: akathisia (21.2%); parkinsonism, including moderate to severe akinesia, (15.4%); and dyskinesia (2.3~
According to F~E~A~ (1959), less severely ill patients are particularly likely to appear worse on the more potent phenothiazines because of akinetic and hyperkinetie manifestations with accompanying experiences of subjective distress.
Both clinical and controlled studies have consistently shown extrapyramidal reactions to be related to drug potency and dependent to a large extent on individual susceptibility (MYx~T~OPOULOS et al., 1962). Evidence so far indicates that they appear to be reversible effects, ehminated or controlled by reduction of dosage, mild sedation, or anti-parkinson drugs (AYD, 1960; MED~A et al, 1962).
The present investigation undertook to explore further the question of extrapyramidM sensitivity and phenothiazine drug action. Since there was already evidence of the reversibility of phenothiazine extrapyramidal effects, the study attempted to determine the extent to which such effects could be controlled by the prophylactic use of an anti-parkinson agent. For this purpose, effects with the drug perphenazine were considered typical of the kind of extrapyramidM action clinicians have come to expect of the more potent phenothiazinesL Benztropine mesylate, one