[Evaluation of the 24-hour effect of a once-daily antihypertensive drug on the diurnal blood pressure profile].

The efficacy and duration of action of antihypertensive drugs can be objectively investigated by means of non-invasive 24-hour blood pressure profiles. Nocturnal measurements, however, are at times not well accepted by the patients, due to the sleep disturbances which may occur, and the results may therefore be difficult to interpret. To overcome this problem we used diurnal (8 am to 10 pm) profiles in the study of the efficacy of isradipine SRO (5 mg). 22 patients were included in this open, cross-over study; isradipine was given at either 9 am or 9 pm. The results demonstrate that isradipine SRO lowers blood pressure over a period of 24 hours. The magnitude of this effect is reduced, however, 22 or 13 hours (for systolic and diastolic blood pressure respectively) subsequent to ingestion of the drug. In conclusion, we have shown that diurnal blood pressure profiles minimize the risk of incomplete recordings and render the investigation more acceptable to the patient. The methodology is, therefore, practical and useful in daily medical practice.