The beta-blocking effect of diacetolol in humans and its relationship to plasma levels.

The beta-blocking action of diacetolol was studied in six healthy subjects after oral administration of placebo, 200, 400, and 600 mg diacetol in random order by means of exercise tests. Diacetolol plasma levels were determined by the HPLC method. Drug administration had No significant influence on resting heart rate and resting systolic or diastolic blood pressure. The beta-adrenoreceptor blockade was expressed as percentage reduction of exercise heart rate (delta FC%). This value increased with the size of the dose. There was a linear relationship between delta FC% and log plasma levels of diacetolol for each subject, except one. Analysis of variance did not provide a common regression line for all subjects.