Information about Phenoxybenzamine

Phenoxybenzamine Uses

Phenoxybenzamine is used in the treatment of Hypertension (high blood pressure).

How Phenoxybenzamine works

Phenoxybenzamine is an alpha blocker which helps reduce blood pressure in pheochromocytoma (a tumour of the adrenal gland). It works by opposing the action of certain hormones released from the tumor that cause the blood vessels to narrow and raise blood pressure.

Common side effects of Phenoxybenzamine

Ejaculation disorder, Constriction of pupil, Orthostatic hypotension (sudden lowering of blood pressure on standing), Nasal congestion (stuffy nose), Increased heart rate, Vomiting, Nausea
Written By
Reviewed By
MD (Pharmacology), MBBS
Last updated:
18 Feb 2020 | 11:51 AM (UTC)
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Available Medicine for Phenoxybenzamine

FenoxeneSamarth Life Sciences Pvt Ltd
484 to ₹23852 variant(s)
BiophenoxUnited Biotech Pvt Ltd
17051 variant(s)
ZaxybenMolekule India Pvt Ltd
17681 variant(s)

Expert advice for Phenoxybenzamine

  • Phenoxybenzamine can be taken with or without food or as advised by the doctor.
  • Take it in addition to lifestyle modification with regular exercise, a balanced diet, and smoking cessation.
  • To lower the chance of feeling dizzy or passing out, rise slowly if you have been sitting or lying down.
  • It may cause dizziness or sleepiness. Do not drive or do anything that requires concentration until you know how it affects you.
  • Inform your doctor if you are pregnant, planning pregnancy or breastfeeding.

Frequently asked questions for Phenoxybenzamine


Q. How long should Phenoxybenzamine be taken?

You should take it as long as your doctor has recommended it to you. Do not stop taking it without talking to you doctor first. Long-term use of Phenoxybenzamine is not recommended as cases of developing cancer have been reported. Consult your doctor before starting the treatment.

Q. Who should not use Phenoxybenzamine?

Phenoxybenzamine should not be given to patients who are allergic to it. Additionally, in patients with a recent history (within the last month) of stroke or heart attack, Phenoxybenzamine should be avoided. Tell your doctor if any of these conditions apply to you.

Q. How does Phenoxybenzamine cause tachycardia?

Phenoxybenzamine belongs to alpha receptor blockers class of medicines. Alpha receptors blockade decreases resistance thereby increasing blood flow to the skin, mucosa (membrane that lines various cavities of the body), and abdominal viscera (membrane lining the abdomen). This results in lowering of blood pressure. This reduced blood pressure and increased release of chemical messenger (noradrenaline) results in reflex tachycardia.

Q. Why is Phenoxybenzamine used for pheochromocytoma?

Phenoxybenzamine helps in reducing the increased blood pressure caused by Pheochromocytoma. It is a tumor of the adrenal glands. It causes the release of certain substances (catecholamines) from the adrenal glands into the bloodstream in large quantities, causing high blood pressure. Phenoxybenzamine works by blocking alpha receptors, thereby decreasing blood pressure.

Q. What are the advantages of using Phenoxybenzamine in pheochromocytoma?

Using Phenoxybenzamine in pheochromocytoma is beneficial due to its long duration of action leading to twice daily dosing. Along with that, it prevents episodic increase of catecholamine releases during pre- and post-operative period which helps in keeping the blood pressure under control during surgical procedures.

Q. What are other uses of Phenoxybenzamine?

Phenoxybenzamine is sometimes effective in treating Raynaud’s phenomenon. This condition results in discoloration of the fingers and/or toes after exposure to changes in temperature (cold or hot) or emotional events. Phenoxybenzamine is also useful in treating frostbite.

Q. Can Phenoxybenzamine affect sex life?

Yes, use of Phenoxybenzamine may affect sex life. It may cause inhibition of ejaculation and may make the patient impotent. However, these effects are generally mild and lasts for only a short time. Discuss with your doctor if you experience this.

Q. What are the symptoms of overdose of Phenoxybenzamine?

Taking more than the recommended dose of Phenoxybenzamine may cause significant decrease in blood pressure which may last for several hours, increased heartbeat, and one may even collapse. If you accidentally take an overdose of this medicine, contact your doctor and seek immediate medical help.


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