enalaprilat-anhydrous and urapidil

Hypertensive crises are a commonly observed problem in an emergency department. The aim of the study was to evaluate the efficacy and safety of different antihypertensive agents in the treatment of patients with hypertensive crises. 168 patients (mean age: 52 +/- 12 years) admitted to the emergency department with a hypertensive urgency (systolic (SBP) blood pressure > 210 mm Hg and/or diastolic (DBP) blood pressure > 110 mm Hg) or a hypertensive emergency (DBP > 100 mm Hg and evidence of end-organ damage) were included into the study protocol. Blood pressure (BP) was measured every 5 min automatically using a noninvasive BP measurement unit. After a resting period of 30 min the patients received the following drugs: 5 mg enalaprilat intravenous (n = 43) or 25 mg urapidil intravenous (n = 48) or 10 mg nifedipine-capsule sublingual (n = 47) or 2 x 5 mg nifedipine-spray sublingual (n = 30). The aim of treatment was to reduce SBP below 180 mm Hg and DBP below 95 mm Hg within 45 min after start of treatment. When evaluating the response rates the highest rate was observed in the urapidil group (96%). The response rate of enalaprilat and both preparations of nifedipine were similar (70-72%). The rate of major side effects was higher in the urapidil compared to the other drugs (4% vs 2% in the nifedipine-group or 0% in the enalaprilat-group). All four drugs are suitable in the treatment of patients with hypertensive crisis in the emergency department. Urapidil should be used as a first choice drug in critically ill patients with hypertensive crisis due to its higher response rate.

Topics: Adult; Aged; Antihypertensive Agents; Blood Pressure; Emergency Medical Services; Enalaprilat; Female; Humans; Hypertension; Male; Middle Aged; Nifedipine; Piperazines; Treatment Outcome

Topics: Antihypertensive Agents; Brain Diseases; Enalaprilat; Humans; Hypertension; Piperazines

The adrenoceptor blocking properties and hypotensive effects of the alpha-1 blocking agents urapidil and prazosin were compared in conscious instrumented rats. Both urapidil and prazosin in i.v. doses of 3 and 6 mg/kg and 0.125 and 0.25 mg/kg, respectively, blocked the pressor response to the alpha-1 adrenoceptor agonist phenylephrine. The hypotensive effects of urapidil and prazosin in these doses were equivalent. Mechanisms of the blood pressure compensation to urapidil-induced hypotension were examined with the arginine vasopressin (AVP) antagonist, d(CH2)5Tyr(Me)AVP, and the angiotensin converting enzyme inhibitor, MK-422. Urapidil alone (6 mg/kg i.v.) and after the AVP antagonist caused a similar degree of hypotension (22 and 15% decrease, respectively, in mean blood pressure). When the alpha-1 antagonist was administered after converting enzyme inhibition, it caused a significantly greater decrease in blood pressure (37%) than in the previous two groups, but not different from that obtained after combined AVP antagonism and converting enzyme inhibition (30% decrease). These results indicate that the renin-angiotensin system compensates for the hypotensive effect due to alpha-1 adrenoceptor blockade, whereas AVP, even assuming that the circulating level was increased by urapidil, was without effect on blood pressure.

Topics: Adrenergic alpha-Antagonists; Analysis of Variance; Animals; Antihypertensive Agents; Arginine Vasopressin; Blood Pressure; Enalapril; Enalaprilat; Male; Phenylephrine; Piperazines; Prazosin; Rats; Rats, Inbred Strains; Renin-Angiotensin System