Effects of phencyclidine and stress on plasma creatine phosphokinase (CPK) and aldolase activities in man

Phencyclidine (Sernyl, Phen) is a potent psychotomimetic drug in man. In conjunction with restraint stress, Phen produces increased plasma creatine phosphokinase (CPK) and aldolase (Ald) activities and skeletal muscle pathology in rats. Increased plasma CPK and Ald activities and skeletal muscle pathology are found in some acutely psychotic patients. It was therefore of interest to determine if Phen increased plasma CPK or Ald levels in man. Four of seven subjects had no elevations of plasma CPK or Ald activity either before or after Phen, 0.1 mg/kg, i.v. One subject had increased CPK levels which began 1 h after Phen. Two subjects had increased Ald and/or CPK levels which began within 24 h before Phen administration and which persisted or increased for at least 24 h after Phen. The plasma enzyme changes occurred in those subjects who showed the most pronounced cognitive disruption after Phen. The effects of stress and Phen on plasma CPK and Ald levels and its implications for the study of muscle abnormalities in psychotic patients are discussed.