Treatment of hypertensive emergencies: classic and newer approaches

Serious complications of treatment in hypertensive crises have been reported for nearly all drugs, so that testing of further antihypertensive drugs in the management of hypertensive emergencies is desirable. In the present study, the clinical efficacy and effects on cardiac function of intravenously infused clonidine were tested in 20 hypertensives with severely elevated blood pressure (diastolic blood pressure over 130 mm Hg). In all patients, the normalization of blood pressure was achieved together with a reduction in total and peripheral vascular resistance. Heart rate showed a slight and brief decrease. Cardiac performance (determined by radionuclide angiocardiography) was improved as indicated by the significant increase in ejection fraction and decrease in both end-diastolic and end-systolic volumes. The dosage of clonidine was progressively increased until a normal blood pressure (mean blood pressure less than or equal to 105 mm Hg) was obtained. The total mean dose required for control of blood pressure was 403 +/- 97.8 micrograms, administered over a mean period of 32 +/- 5.9 min. Side effects, represented by dry mouth and drowsiness, were well tolerated and of short duration. It is concluded that clonidine is an effective and safe alternative in the treatment of hypertensive emergencies.