Pharmacological basis of the antihypertensive action of calcium entry blockers.

Calcium entry blockers or calcium antagonists have been recognized as useful antihypertensive drugs, although their definite position in the management of hypertensive disease remains to be established. The present survey deals with the pharmacological basis of their antihypertensive action, side effects, contraindications, and interactions with other drugs. The antihypertensive effect of the various calcium entry blockers is fully explained by arteriolar dilatation, thus leading to a reduction in total peripheral resistance. At a cellular level this effect is assumed to be induced by the selective inhibition of the slow inward current that is carried by calcium ion fluxes. Furthermore, the interaction with vascular postsynaptic alpha 2-adrenoceptor-mediated vasoconstriction may also contribute to vasodilatation.