Phenoxybenzamine is a non-selective, irreversible alpha-adrenergic antagonist primarily used to manage pheochromocytoma-related hypertension and conditions involving excessive sympathetic activity. By blocking alpha-1 and alpha-2 receptors, it causes vasodilation and reduces blood pressure, helping to control the severe hypertensive episodes associated with catecholamine-secreting tumors. Developed in the 1950s, phenoxybenzamine was one of the first long-acting alpha blockers, representing a significant advance in cardiovascular pharmacology by providing a tool for preoperative management of pheochromocytoma and other hyperadrenergic states. Over time, its use expanded to treat Raynaud’s phenomenon, benign prostatic hyperplasia symptoms, and certain cases of chronic hypertension, although newer selective alpha blockers have largely replaced it for routine therapy. Its introduction highlighted the therapeutic potential of irreversible receptor blockade, offering prolonged efficacy and establishing a foundation for the development of modern adrenergic antagonists.
