Pheochromocytoma 3 adrenergic receptor antagonists

Epinephrine can produce severe hypertension when used with a nonselective P receptor antagonist due to the unopposed stimulation of a receptors when vascular receptors are blocked. Such paradoxical hypertensive responses to p adrenergic receptor antagonists have been observed in patients with hypoglycemia or pheochromocytoma, during withdrawal from clonidine, following administration of Epi as a therapeutic agent, or in association with the iUicit use of cocaine. 

Trade names Dibenyline Dibenzyline (Wellspring) Dibenzyran Indications Pheochromocytoma Category Adrenergic alpha-receptor antagonist Half-life 24 hours... 

Receptor antagonists are not the drugs of choice in patients with pheochromocytoma, because a vasoconstrictor response to epinephrine can still result from activation of unblocked vascular (X2 adrenergic receptors, Receptor antagonists are attractive drugs for hypertensive patients with benign prostatic hyperplasia, since they also improve urinary symptoms. 

---