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Introduction of
Phentolamine Mesylate
Prophylaxis or
treatment of hypertension in pheochromocytoma as a result of
stress or manipulation prior to or during surgery. Dermal
necrosis and sloughing following IV use or extravasation of
norepinephrine or dopamine. To test for pheochromocytoma (not
the method of choice). Investigational: Hypertensive
crisis secondary to MAO inhibitor/sympathomimetic amine
interactions; rebound hypertension due to withdrawal of
clonidine, propranolol, or other antihypertensive drugs. In
combination with papaverine as an intracavernous injection for
impotence.
Kinetics of Phentolamine Mesylate
Phentolamine competitively blocks both presynaptic (alpha-2)
and postsynaptic (alpha-1) adrenergic receptors producing
vasodilation and a decrease in peripheral resistance. The drug
has little effect on BP. In CHF, phentolamine reduces
afterload and pulmonary arterial pressure as well as increases
CO. Onset (parenteral): Immediate. Duration: Short. Poorly
absorbed from the GI tract. About 10% excreted unchanged in
the urine after parenteral use.
Side Effects of Phentolamine
Mesylate
CV:
Acute and prolonged hypotension, tachycardia,
MI, cerebrovascular spasm,
cerebrovascular occlusion
and arrhythmias, especially after parenteral administration.
Orthostatic hypotension, flushing. GI: N&V, diarrhea. Other:
Dizziness, weakness, nasal stuffiness.
Disclaimer:
Information on this page is provided for general
information purposes. You should not make a clinical treatment
decision based on information contained in this page without
consulting other references including the package insert of
the drug, textbooks and where relevant, expert opinion. We
cannot be held responsible for any errors you make in
administering drugs mentioned on this page, nor for use of any
erroneous information contained on this page.
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