phentolamine /fentol″əmēn/ , an alpha1-adrenergic receptor blocker. ▪ INDICATIONS: It is prescribed in the control of symptoms of pheochromocytoma before and during surgery and for dermal necrosis and sloughing after extravasation of parenteral drugs with alpha-adrenergic effects (e.g., norepinephrine, epinephrine, dopamine). ▪ CONTRAINDICATIONS: History of myocardial infarction, angina, coronary artery disease, cerebrovascular disease, renal impairment, or known hypersensitivity to this drug prohibits its use. ▪ ADVERSE EFFECTS: Among the more serious adverse effects are tachycardia, cardiac arrhythmias, anginal pain, and hypotension.
