phentolamine mesylate

Also found in: Dictionary, Thesaurus.
Related to phentolamine mesylate: Regitine

phentolamine mesylate

Rogitine (CA) (UK)

Therapeutic class: Diagnostic agent, antihypertensive agent in pheochromocytoma

Pregnancy risk category C


Competitively blocks postsynaptic (alpha1) and presynaptic (alpha2) adrenergic receptors. Acts on arterial tree and venous bed, reducing total peripheral resistance and lowering venous return to heart.


Powder for injection: 5 mg

Indications and dosages

To prevent or control hypertensive episodes before or during pheochromocytomectomy

Adults: 5 mg I.V. or I.M. 1 to 2 hours before surgery, then 5 mg I.V. during surgery as indicated

Children: 1 mg I.V. or I.M. 1 to 2 hours before surgery, then 1 mg I.V. during surgery as indicated

To aid pheochromocytoma diagnosis

Adults: 2.5 or 5 mg (in 1 ml of sterile water) by I.V. injection; record blood pressure q 30 seconds for 3 minutes, then q minute for next 7 minutes. Or 5 mg (in 1 ml sterile water) I.M.; record blood pressure q 5 minutes for 30 to 45 minutes.

To prevent or treat dermal necrosis after norepinephrine extravasation

Adults: For prevention, add 10 mg to each liter of I.V. solution containing norepinephrine. For treatment, inject 5 to 10 mg in 10 ml of normal saline solution into extravasated area within 12 hours.

Off-label uses

• Hypertensive crisis caused by MAO inhibitors

• Rebound hypertension caused by withdrawal of clonidine, propranolol, or other antihypertensives

• Erectile dysfunction (given with papaverine)


• Hypersensitivity to drug

• Coronary artery disease

• Myocardial infarction (MI) or history of MI

• Coronary insufficiency

• Angina


Use cautiously in:

• patients receiving cardiac glycosides concurrently

• pregnant or breastfeeding patients.


• Reconstitute powder by diluting with 1 ml of sterile water for injection.

• For pheochromocytoma diagnosis, withhold sedatives, analgesics, and nonessential drugs for 24 to 72 hours before test (until hypertension returns). Keep patient supine until blood pressure stabilizes; then rapidly inject drug I.V. Maximum effect usually occurs within 2 minutes of dosing.

Adverse reactions

CNS: weakness, dizziness

CV: tachycardia, acute and prolonged hypotension, orthostatic hypotension, arrhythmias

EENT: nasal congestion

GI: nausea, vomiting, diarrhea

Skin: flushing


Drug-drug. Ephedrine, epinephrine: antagonism of these drugs' effects

Drug-herbs. Ephedra (ma huang): antagonism of vasoconstrictive effects

Patient monitoring

• When using for norepinephrine extravasation, monitor injection site closely and assess blood pressure, heart rate, and respiratory rate.

• For pheochromocytoma diagnosis, monitor blood pressure. In pheochromocytoma, systolic and diastolic pressures drop immediately and steeply. Monitor and record blood pressure immediately after injection, at 30-second intervals for first 3 minutes, and at 1-minute intervals for next 7 minutes. Systolic decrease of 60 mmHg and diastolic decrease of 25 mmHg within 2 minutes after I.V. administration indicates a positive reaction for pheochromocytoma.

Patient teaching

• Explain drug administration procedure.

Instruct patient to promptly report adverse reactions. Assure him he'll be monitored closely.

• Tell patient to withhold other drugs (especially sedatives and analgesics) for at least 24 hours before pheochromocytoma testing, if appropriate.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and herbs mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved