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Phenoxybenzamine Side Effects

Medically reviewed by Drugs.com. Last updated on Aug 13, 2024.

Applies to phenoxybenzamine: oral capsule.

In rats and mice, phenoxybenzamine has been found to increase the risk of development of malignant tumors. It is not known if phenoxybenzamine increases the chance of tumors in humans.

Common side effects of phenoxybenzamine

Some side effects of phenoxybenzamine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common side effects

  • dizziness or lightheadedness, especially when getting up from a lying or sitting position
  • fast heartbeat
  • pinpoint pupils
  • stuffy nose

Less common side effects

  • confusion
  • drowsiness
  • dryness of mouth
  • headache
  • lack of energy
  • sexual problems in males
  • unusual tiredness or weakness

Serious side effects of phenoxybenzamine

Along with its needed effects, phenoxybenzamine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Managing side effects (general information)

For healthcare professionals

Applies to phenoxybenzamine: compounding powder, oral capsule.

Cardiovascular adverse events

Cardiovascular side effects have included postural hypotension and tachycardia. These symptoms are evidence of adrenergic blockade and vary according to the degree of blockade.[Ref]

Genitourinary

Genitourinary side effects have included inhibition of ejaculation. This symptom is indicative of adrenergic blockade and varies according to the degree of blockade.[Ref]

Respiratory

Respiratory side effects have included nasal congestion. This symptom is indicative of adrenergic blockade and varies according to the degree of blockade.[Ref]

Ocular

Ocular side effects have included miosis. This symptom is indicative of adrenergic blockade and varies according to the degree of blockade.[Ref]

Nervous system

Nervous system side effects have included drowsiness and fatigue.[Ref]

Gastrointestinal

Gastrointestinal side effects have included gastrointestinal irritation.[Ref]

References

1. "Product Information. Dibenzyline (phenoxybenzamine)." SmithKline Beecham

Further information

Phenoxybenzamine side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer