[Effect of droperidol on the creatine phosphokinase activity in acute myocardial infarct]

In 141 patients with acute myocardial infarction, creatine phosphokinase isoenzyme (CPK-MB) was determined by the activation method with dithiothreitol (RAO et al.: Clin. Chim. Acta 21, 1612 [1975]). 15 out of 16 patients with atypical negative CPK-MB values within the first 3 days after infarction had been treated with 5-10 mg droperidol, a neuroleptic drug dispensed for its antiemetic effect. In a prospective study in 7 patients, CPK-MB determined serially showed a decrease or persistently low or negative values within 1 minute after injection of 5 mg droperidol and lasting 24-36 hours after injection. In contrast, CPK-MB determined by immunoprecipitation did not change its typical pattern after use of droperidol. Hence, negative or low values of CPK-MB in acute myocardial infarction must be expected after droperidol if determination is by the activation method with dithiothreitol.