Combined action drugs in the treatment of hypertension.

Combined action drugs is a term applied to describe antihypertensive agents which lower blood pressure by interference with more than one physiological mechanism contributing to the genesis and maintenance of hypertension. In this group numerous compounds have been developed which have an antagonistic effect on beta-adrenoceptors and at the same time achieve other effects, for example vasodilatation, usually through an antagonistic effect at alpha-adrenoceptor sites. In view of the multifactorial aetiology of essential hypertension, it is logical to try to reduce the elevated arterial pressure in this condition by interfering with more than one mechanism. It seems to be important that a vasodilating component is present, since the hallmark of established essential hypertension is increased total peripheral resistance. Thus, a combined action drug with a vasodilating component will lower blood pressure and at the same time maintain organ perfusion. A beta-adrenoceptor blocking component is also desirable in view of the proven secondary prevention against coronary heart disease obtained with beta-blockers and the proposed primary preventive effect attributable to beta-blockade. Finally, since the combination of beta-blockade and vasodilatation (e.g. due to peripheral alpha 1-blockade) usually does not induce metabolic disturbances, agents of this kind are not likely to elevate serum lipoproteins. Thus, this paper will briefly review the use of the combined action drug carvedilol in the treatment of hypertension.