Nifedipine In Hypertensive Emergencies

• Published in: British medical journal (Clinical research ed.) Vol. 286; no. 6358; pp. 19 - 21
• Main Authors: Bertel, O., Conen, D., Radü, E. W., Müller, J., Lang, C., Dubach, U. C.
• Format: Journal Article
• Language: English
• Published: England British Medical Association 01.01.1983; BMJ Publishing Group LTD
• Subjects: Adult; Aged; Antihypertensives; Blood flow; Blood pressure; Blood Pressure - drug effects; Cerebrovascular Circulation - drug effects; Clinical Trials as Topic; Clonidine - therapeutic use; Diastolic blood pressure; Emergencies; Emergency departments; Heart rate; Heart Rate - drug effects; Humans; Hypertension; Hypertension - drug therapy; Hypertensive emergency; Middle Aged; Nifedipine - therapeutic use; Placebos; Pyridines - therapeutic use; Random Allocation; Sodium
• ISSN: 0267-0623
• DOI: 10.1136/bmj.286.6358.19

The effects and safety of using oral nifedipine 10-20 mg as acute antihypertensive treatment were studied in a single-blind placebo-controlled study of 25 consecutive patients with very high blood pressure requiring emergency reduction. In addition the effect of this treatment on cerebral blood flow was investigated using xenon-133 in 10 patients randomly allocated to receive oral nifedipine or intravenous clonidine. Whereas placebo did not alter the blood pressure, oral nifedipine significantly reduced the systolic and diastolic blood pressures in all 25 patients (from 221 ± 22/126±14 mm Hg to 152±20/89±12 mm Hg after 30 minutes, p <0.001). Heart rate increased from 74±11 to 84±11 beats/minute (p <0.01); this effect was inversely related to age (r=-0.65, p <0.01). The falls in systolic and diastolic blood pressures were closely related to the blood pressures before treatment (r=0.67, p <0.001 for systolic, and r=-0.58, p <0.01 for diastolic values). No serious unwanted effects were observed. Measurement of cerebral blood flow after nifedipine showed an increase in flow in four out of five patients. Clonidine, by contrast, reduced cerebral blood flow in all patients by up to 28%. Nifedipine is a simple, effective, and safe alternative drug for managing hypertensive emergencies, especially when continuous monitoring of the patient cannot be guaranteed.