Alpha adrenergic receptor antagonists- phentolamine 【therapeutic uses.】 a.pheochromocytoma b.Hypertensive emergency C. peripheral vascular disease:vasospasm of Raynaud's disease and frostbite d.Local vasoconstrictor excessAlpha adrenergic receptor antagonists -- phentolamine 【therapeutic uses 】 a. pheochromocytoma b. Hypertensive emergency c. peripheral vascular disease: vasospasm of Raynaud's disease and frostbite d. Local vasoconstrictor excess