Comparative study of the efficacy of captopril at a single daily dose of 100 mg and at a twice daily dose of 50 mg by measuring ambulatory pressure over 24 hours.

Variations in blood pressure were investigated by an automatic, non-invasive ambulatory method in 9 subjects with essential hypertension. Recordings were made after 6 week periods during which captopril was taken either once or twice daily, in a double-blind cross-over study. Although the effects of captopril administration either once or twice daily were broadly similar, there was a significant decrease in diastolic blood pressure values on the once-daily regimen. These results suggests that treatment once a day can advantageously replace twice-daily treatment.