Nifedipine in hypertensive emergencies.

Abstract

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 1 20/89 12 mm Hg after 30 minutes, p <0001). Heart rate increased from 74 11 to 84-+ 11 beats/minute (p<001); 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-=067, 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.

Pharmacological interventions for hypertensive emergencies: a Cochrane systematic review

“…43 One trial did not report any of the outcomes of interest (1 trial). 44 Two trials did not fulfil blood pressure threshold criteria. 45,46 One was a cross-over trial.…”

Clinical presentation and management of patients with uncontrolled, severe hypertension: results from a public teaching hospital

“…Accordingly, in the absence of detailed management guidelines and algorithms supported by data from the appropriate clinical trials, practitioners employ a number of diverse protocols, with quite varied results. [22][23][24][25][26][27][28][29][30][31][32][33] …”

Acute treatment of hypertensive crisis with nifedipine.

“…An extra advantage of a calcium antagonist in comparison with other vasodilators might be, that it selectively increases cerebral and cardiac blood flow as has been shown in animal experiments (Aboul-Khair et al, 1981). Recently, Bertel et al (1983) demonstrated in five patients with severe hypertension, that cerebral blood flow remained constant or increased after emergency treatment with nifedipine. The observed increases in heart rate and the absence of an increase of the P-R interval were somewhat unexpected, since nifedipine has a direct negative chronotropic effect.…”

“…Most of the patients investigated until now had a normal renal function. Nifedipine has been used in only a few cases of hypertensive crisis (Murakami et al, 1972;Ueda et al, 1979;Bertel et al, 1983 iosonde 1217) from 30 min before until 60 min after the administration of nifedipine. With this device diastolic pressure is determined at a level comparable to Korotkoff sound V. Heart rates were calculated from ECG-strips taken immediately before and at 10 min intervals during 1 h after the nifedipine administration.…”