Accumulated evidence has indicated that the failure of blood pressure control with antihypertensive therapy to reduce the incidence of myocardial infarction may be due to unfavorable effects of drug therapy on other cardiovascular risk factors, particularly lipid concentrations. Several studies have demonstrated that beta-blocking drugs increase serum triglyceride concentration and reduce high-density lipoprotein cholesterol concentration, both of which are risk factors for coronary artery disease. However, several investigators have reported that prazosin, an alpha-adrenergic blocking agent, does not cause adverse changes in those lipid parameters or in the cholesterol ratio. If one considers the net effect of antihypertensive therapy to be the reduction of blood pressure plus the alterations in lipid metabolism, the metabolic response to a drug may be an important determinant of the overall effectiveness of treatment and a deciding factor in the choice among available antihypertensive agents.