Adrenergic blockade

Traditionally, a combination of peripherally acting a- and b-receptor blockers have been used. Phenoxybenzamine, phentolamine, bethanidine, and chlorpromazine can block a receptors. Chlorpromazine is probably the best because of its additional central sedative effects. Propranolol (pure b-receptor blocker) and labetalol (a-and b-receptor blocker) have had limited success. We do not advise unopposed b-blockade as deaths from acute congestive cardiac failure have occurred. Removal of b-mediated vasodilatation in the muscle causes a rise in systemic vascular resistance, and the b-blocked myocardium may not be able to maintain cardiac output. The short-acting intravenous b-blocker esmolol is useful for controlling the tachycardia and hypertension of the crises; however, catecholamine levels remain raised (Lipman jnd Oh 1.9.9.6). This is worrying because excessive catecholamine secretion is associated with myocardial damage.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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