Alpha Blockers

Non-selective alpha-adrenergic antagonists

Phenoxybenzamine(Dibenzyline) is an irreversible, non-selective alpha blocker,

classically used in the pre-operative treatment of pheochromocytoma

Phentolamine (OraVerse) is like phenoxybenzamine, but is reversible. It may

also be used in pheochromocytoma.

Effects

• Alpha-1 blockade results in widespread vasodilation, causing a decrease in blood pressure and a reflex tachycardia
• Mild increase in cardiac output