What is the use of Phentolamine (Regitine)?

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Last updated: April 24, 2025 • View editorial policy

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From the Guidelines

Phentolamine is recommended as a first-line treatment for hypertensive emergencies caused by pheochromocytoma or catecholamine excess, with an initial IV bolus dose of 5 mg, and additional bolus doses every 10 min as needed to lower BP to target. This recommendation is based on the most recent and highest quality study available, which is the 2020 international society of hypertension global hypertension practice guidelines 1.

Key Points

  • Phentolamine is an alpha-adrenergic blocking agent that works by blocking alpha-1 and alpha-2 adrenergic receptors, preventing catecholamines like norepinephrine from binding, which results in vasodilation and decreased blood pressure.
  • The typical adult dosage for hypertensive emergencies is 5 mg administered intravenously, with effects beginning within 2 minutes and lasting 10-15 minutes.
  • Phentolamine is used to treat hypertensive emergencies induced by catecholamine excess, such as pheochromocytoma, interactions between monoamine oxidase inhibitors and other drugs or food, cocaine toxicity, amphetamine overdose, or clonidine withdrawal.
  • Common side effects include hypotension, tachycardia, dizziness, and flushing.

Clinical Considerations

  • Phentolamine should be used with caution in patients with coronary artery disease, myocardial infarction, or cerebrovascular disease.
  • Beta-blockers should only be used once alpha-blockers have been introduced to avoid acceleration of hypertension in patients with pheochromocytoma.
  • Phentolamine can be used locally to treat tissue damage from extravasation of vasoconstrictive drugs and has a specialized dental formulation (OraVerse) to reverse local anesthetic-induced numbness.

Evidence Summary

The 2020 international society of hypertension global hypertension practice guidelines 1 recommend phentolamine as a first-line treatment for hypertensive emergencies caused by pheochromocytoma or catecholamine excess. The 2019 esc council on hypertension position document on the management of hypertensive emergencies 1 also supports the use of phentolamine in these situations. The 2018 acc/aha/aapa/abc/acpm/ags/apha/ash/aspc/nma/pcna guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1 provides additional guidance on the use of phentolamine in hypertensive emergencies.

From the FDA Drug Label

Phentolamine Mesylate for Injection is indicated for the prevention or control of hypertensive episodes that may occur in a patient with pheochromocytoma as a result of stress or manipulation during preoperative preparation and surgical excision. Phentolamine Mesylate for Injection is indicated for the prevention or treatment of dermal necrosis and sloughing following intravenous administration or extravasation of norepinephrine. Phentolamine Mesylate for Injection is also indicated for the diagnosis of pheochromocytoma by the phentolamine blocking test.

The primary uses of phentolamine are:

  • Prevention or control of hypertensive episodes in patients with pheochromocytoma
  • Prevention or treatment of dermal necrosis and sloughing following intravenous administration or extravasation of norepinephrine
  • Diagnosis of pheochromocytoma by the phentolamine blocking test 2 2

From the Research

Phentolamine Overview

  • Phentolamine is an intravenous antihypertensive agent used for the treatment of hypertensive emergencies 3
  • It is characterized by a short onset and offset of action and predictable responses during dosage adjustments to reach blood pressure goals 3

Clinical Uses

  • Phentolamine has been used to treat congestive heart failure due to its vasodilating action and positive inotropic effects 4
  • It has also been used to improve left ventricular function in acute myocardial infarction and to suppress ventricular premature beats and supraventricular premature beats 4
  • Phentolamine can be used as a provocative test in idiopathic hypertrophic subaortic stenosis and has been advocated for the treatment of shock 4

Limitations and Interactions

  • Phentolamine has no clinically useful anti-hypertensive effect in conjunction with beta-blockers in patients with essential hypertension 5
  • The experience with phentolamine as an antiarrhythmic agent is still limited, and its use in relieving angina pectoris requires confirmation by additional clinical studies 4

Current Guidelines and Management

  • The selection of phentolamine as an antihypertensive agent should be based on its pharmacology and patient-specific factors, such as comorbidity and the presence of end-organ damage 3
  • Current guidelines emphasize the importance of careful and effective strategies to reduce blood pressure and diminish the effects of pressure-mediated injury in hypertensive emergencies 6

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

3
Research

Intravenous therapy for hypertensive emergencies, part 2.

American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists, 2009

4
Research

Phentolamine.

American heart journal, 1976

6
Research

Evaluation and management of hypertensive emergency.

BMJ (Clinical research ed.), 2024

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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