Abstract

Hypertension can be controlled by reducing cardiac output or peripheral resistance or a combination of both. Diazoxide (Eudemine), hydralazine* (Apresoline) and minoxidil all reduce peripheral resistance by direct arteriolar vasodilatation, without sympathetic blockade. They all therefore cause a rise in cardiac output, and a compensatory tachycardia through reflex baroreceptor activity. This increase in cardiac output tends to restore the blood pressure and is associated with palpitations; both can be reduced by using these drugs with a β-blocker whose hypotensive effect is additive.