Urapidil. A reappraisal of its use in the management of hypertension.

UNLABELLED: Urapidil is a peripheral postsynaptic alpha 1-adrenoceptor antagonist with central agonistic action at serotonin 5-HT1A receptors. It reduces blood pressure by decreasing peripheral vascular resistance. Oral urapidil decreases blood pressure in patients with mild to moderate essential hypertension and associated risk factors such as hyperlipidaemia or type 2 (non-insulin-dependent) diabetes mellitus with no effect on heart rate. The antihypertensive efficacy of urapidil is similar to that of most comparators in patients with mild to moderate essential or secondary hypertension and no concomitant risk factors. However, the antihypertensive efficacy of urapidil was lower than that of hydrochlorothiazide in a well designed trial. Lipid levels and glucose metabolism are not adversely affected and may improve with urapidil in patients with lipid or glucose abnormalities. Urapidil can be safely combined with other antihypertensive agents such as hydrochlorothiazide and nifedipine and improves blood pressure control in previous nonresponders to monotherapy. Intravenous urapidil reduces blood pressure in patients with pre-eclampsia or hypertension in pregnancy and in patients with hypertensive crises or peri- or postoperative hypertension. The decrease in blood pressure is similar to that observed after nifedipine, enalaprilat, sodium nitroprusside and dihydralazine, greater than that of ketanserin according to 1 larger study, and greater than that of sublingual nitroglycerin in 1 trial in patients with nonsurgical hypertensive crises and pulmonary oedema. However, more patients responded to treatment with urapidil than with enalaprilat or nifedipine. Heart rate is less likely to be altered by urapidil than with some comparator drugs. Urapidil appears to be well tolerated, with most adverse events being mild and transient. The incidence of adverse events with urapidil is similar to that with prazosin, metoprolol, atenolol, sodium nitroprusside and hydrochlorothiazide and less than that with nifedipine and clonidine. Urapidil may not be as well tolerated as captopril and, in 1 study, more urapidil than nitrendipine recipients discontinued treatment because of adverse events.
CONCLUSIONS: urapidil reduces blood pressure without altering heart rate. The oral formulation is an effective choice in patients with hypertension and concomitant dyslipidaemia or type 2 diabetes mellitus, in whom the drug does not adversely affect and may improve lipid profiles and glucose metabolism. The intravenous formulation is effective in controlling various hypertensive crises and hypertension associated with pregnancy or surgery and is similar to or better than other first-line agents used in these conditions. Thus, urapidil may be a useful alternative to currently available antihypertensive agents.