Alpha adrenergic receptor antagonists phenoxybenzamine Irreversibly block a and a receptors.Long-term a blocker. 【pharmacological properties】 attenuates catecholamine-induced vasoconstriction 【therapeutic uses】 pheochromocytoma peripheral vascular disease: Septic shockAlpha adrenergic receptor antagonists -- phenoxybenzamine • Irreversibly block 1 and 2 receptors. Long-term  blocker. 【pharmacological properties 】 • attenuates catecholamine-induced vasoconstriction 【therapeutic uses 】 • pheochromocytoma • peripheral vascular disease: • Septic shock