Phentolamine Mesylate for Injection Side Effects Center

Last updated on RxList: 8/3/2022
Phentolamine Mesylate for Injection Side Effects Center

What Is Phentolamine Mesylate?

Phentolamine Mesylate for Injection is an antihypertensive indicated for the prevention or control of hypertensive (high blood pressure) episodes that may occur in a patient with pheochromocytoma as a result of stress or manipulation during preoperative preparation and surgical excision, for the prevention or treatment of dermal necrosis and sloughing following intravenous administration or extravasation of norepinephrine, and for the diagnosis of pheochromocytoma by the phentolamine blocking test. Phentolamine mesylate for injection is available in generic form.

What Are Side Effects of Phentolamine Mesylate?

Common side effects of phentolamine mesylate for injection include:

The most common side effects of Phentolamine Mesylate for Injection include:

  • bruising or bleeding at the place of injection,
  • mild burning along the penis,
  • difficulty ejaculating, and
  • swelling or irritation at the injection site

Tell the doctor if you have any side effect that bothers you or that does not go away.

Seek medical care or call 911 at once if you have the following serious side effects:

  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheartedness, or passing out;
  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

Dosage for Phentolamine Mesylate

For preoperative reduction of elevated blood pressure, a dose of 5 mg of phentolamine mesylate (1 mg for children) is injected intravenously or intramuscularly 1 or 2 hours before surgery.

What Drugs, Substances, or Supplements Interact with Phentolamine Mesylate?

Phentolamine mesylate may interact with other drugs. Tell your doctor all medications and supplements you use.

Phentolamine Mesylate During Pregnancy or Breastfeeding

During pregnancy, phentolamine mesylate should be used only if prescribed. It is unknown if this drug is excreted in human milk. Consult your doctor before breastfeeding.

Additional Information

Our Phentolamine Mesylate for Injection Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Salt and sodium are the same. See Answer
Phentolamine Mesylate for Injection Professional Information


Acute and prolonged hypotensive episodes, tachycardia, and cardiac arrhythmias have been reported. In addition, weakness, dizziness, flushing, orthostatic hypotension, nasal stuffiness, nausea, vomiting, and diarrhea may occur.


See DOSAGE AND ADMINISTRATION. Diagnosis of pheochromocytoma, Preparation.

Read the entire FDA prescribing information for Phentolamine Mesylate for Injection (Phentolamine Mesylate)


How to Lower Blood Pressure: Exercise Tips See Slideshow

© Phentolamine Mesylate for Injection Patient Information is supplied by Cerner Multum, Inc. and Phentolamine Mesylate for Injection Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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