Phentolamine

Phentolamine Uses, Dosage, Side Effects, Food Interaction and all others data.

A nonselective alpha-adrenergic antagonist. It is used in the treatment of hypertension and hypertensive emergencies, pheochromocytoma, vasospasm of raynaud disease and frostbite, clonidine withdrawal syndrome, impotence, and peripheral vascular disease.

Phentolamine is indicated for the control of episodes of hypertension and sweating that occur with a disease called pheochromocytoma. If tachycardia is excessive, it may be necessary to use a beta-blocking agent concomitantly. Phentolamine is a long-acting, adrenergic, alpha-receptor blocking agent which can produce and maintain "chemical sympathectomy" by oral administration. It increases blood flow to the skin, mucosa and abdominal viscera, and lowers both supine and erect blood pressures. It has no effect on the parasympathetic system. Phentolamine works by blocking alpha receptors in certain parts of the body. Alpha receptors are present in the muscle that lines the walls of blood vessels. When the receptors are blocked by Phentolamine, the muscle relaxes and the blood vessels widen. This widening of the blood vessels results in a lowering of blood pressure.

Phentolamine
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Dosage
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Interactions
Uses during Pregnancy
Uses during Breastfeeding
Accute Overdose
Food Interaction
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Interaction With other Medicine
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Trade Name	Phentolamine
Availability	Prescription only
Generic	Phentolamine
Phentolamine Other Names	Fentolamina, Phentolamin, Phentolamine, Phentolaminum
Related Drugs	propranolol, labetalol, Inderal, phenoxybenzamine, Normodyne, Trandate, Regitine
Type	Injection
Formula	C₁₇H₁₉N₃O
Weight	Average: 281.3523 Monoisotopic: 281.152812245
Groups	Approved
Therapeutic Class
Manufacturer
Available Country	United States
Last Updated:	September 19, 2023 at 7:00 am

Uses

Phentolamine is an alpha adrenergic antagonist used to reverse soft tissue anesthesia.

Used as an aid for the diagnosis of pheochromocytoma, and may be administered immediately prior to or during pheochromocytomectomy to prevent or control paroxysmal hypertension resulting from anesthesia, stress, or operative manipulation of the tumor. Phentolamine has also been used to treat hypertensive crisis caused by sympathomimetic amines or catecholamine excess by certain foods or drugs in patients taking MAO inhibitors, or by clonidine withdrawal syndrome. Other indications include the prevention of dermal necrosis and sloughing following IV administration or extravasation of norepinephrine, decrease in impedance to left ventricular ejection and the infarct size in patients with MI associated with left ventricular failure, treatment of erectile dysfunction through self-injection of small doses combined with papaverine hydrochloride into the corpus cavernosum, and as an adjunct to the management of cocaine overdose to reverse coronary vasoconstriction following use of oxygen, benzodiazepines,and nitroglycerin.

Phentolamine is also used to associated treatment for these conditions: Hypertensive crisis, Necrosis caused by Administration site extravasation, Norepinephrine, Pheochromocytomas, Anesthesia reversal

How Phentolamine works

Phentolamine produces its therapeutic actions by competitively blocking alpha-adrenergic receptors (primarily excitatory responses of smooth muscle and exocrine glands), leading to a muscle relaxation and a widening of the blood vessels. This widening of the blood vessels results in a lowering of blood pressure. The action of phentolamine on the alpha adrenergic receptors is relatively transient and the blocking effect is incomplete. The drug is more effective in antagonizing responses to circulating epinephrine and/or norepinephrine than in antagonizing responses to mediator released at the adrenergic nerve ending. Phentolamine also stimulates β-adrenergic receptors and produces a positive inotropic and chronotropic effect on the heart and increases cardiac output.