[Dynamics of the anti-anginal effect and of the concentrations of verapamil and its metabolites in the blood serum of patients with stenocardia of exertion].

Anti-anginal effect of verapamil was examined in 17 patients with angina of effort (a 120 mg single dose in 10 patients and a 200 mg dose in 7), using repeated identical treadmill exercise with ECG monitoring. Serum levels of verapamil and its three primary metabolites were measured simultaneously. A correlation was demonstrated between verapamil's anti-ischemic effect and serum concentrations, while no significant contribution of the metabolites to the effect could be shown. In most patients, a marked anti-ischemic effect was observed where blood levels of verapamil exceeded 100 ng/ml. A considerable variability was noted in both the maximum concentrations of the drug and its individual concentrations corresponding to the same anti-anginal effect.