Evaluation of intravenous clonidine in hypertensive emergencies

Parenteral chlorpromazine and frusemide: safe and effective treatment for hypertensive emergencies

Hypertensive emergencies present a difficult problem of management. Although many treatment regimens have been described over the years, their application has presented problems of adverse effects and all have required detailed and intensive supervision of patients. After favourable results obtained in a preliminary study using a combination of parenteral chlorpromazine and frusemide, a 5-year prospective study was conducted using this treatment to produce rapid reduction in blood pressure in patients with acute onset severe hypertension (blood pressure greater than 225/130 mmHg). The patients involved covered a wide range from 22 to 74 years (mean 47 years) and, on subsequent or previous investigation, were all considered to have essential hypertension. Twenty-seven patients were treated successfully with a single administration of the regimen. Two women required a second treatment before adequate control of blood pressure was achieved and 1 man died of extensive dissecting abdominal aortic aneurysm before the effects of the therapy could be fully assessed. The reduction in blood pressure was gradual but progressive over 4 hours and the pattern of response was uniform. No significant adverse effects related to the treatment were found. Only basic measurement of pulse and blood pressure was considered necessary and so this regimen of therapy is suitable for general use even when sophisticated monitoring facilities are not available and staff levels are limited.

Comparison of intramuscularly and intravenously administered clonidine in the treatment of severe hypertension

Twenty-four patients with severe hypertension (diastolic blood pressure (DBP) greater than 14.7 kPa (110 mmHg] were allocated at random to one of two treatment groups. All were given clonidine hydrochloride; twelve by intramuscular injection (Group 1), and 12 by intravenous injection (Group 2). The two routes were equally effective; diastolic blood pressure was reduced to less than 13.3 kPa (100 mmHg) in 11 patients in Group 1 and 10 patients in Group 2. The response in both groups was smooth, with no episodes of severe hypotension. Two patients in each group showed an initial transient pressor response. Clonidine hydrochloride, administered either intravenously or intramuscularly, is an effective treatment for severe hypertension but patients should be observed closely during the first hour after injection.