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Prazosin Side Effects

In Summary

Commonly reported side effects of prazosin include: dizziness. Other side effects include: syncope and drowsiness. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to prazosin: oral capsule, oral tablet

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

Check with your doctor immediately if any of the following side effects occur while taking prazosin:

More Common

  • Dizziness or lightheadedness, especially when getting up from a lying or sitting position
  • fainting (sudden)

Less Common

  • Loss of bladder control
  • pounding heartbeat
  • swelling of the feet or lower legs

Rare

  • Chest pain
  • trouble breathing

Incidence Not Known

  • Painful or prolonged erection of the penis

Some side effects of prazosin 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

Less Common

  • Dryness of the mouth
  • nervousness
  • unusual tiredness or weakness

Rare

  • Frequent urge to urinate
  • nausea

For Healthcare Professionals

Applies to prazosin: compounding powder, oral capsule

General

The most common adverse reactions were postural hypotension, dizziness, headache, drowsiness, lack of energy, weakness, palpitations, and nausea.[Ref]

Cardiovascular

Very common (10% or more): Postural hypotension (up to 14%)

Common (1% to 10%): Palpitations, tachycardia, orthostatic hypotension

Uncommon (0.1% to 1%): Angina pectoris

Rare (less than 0.1%): Bradycardia, flushing, hypotension, vasculitis

Frequency not reported: Angina exacerbation, myocardial infarction[Ref]

Nervous system

Very common (10% or more): Dizziness (up to 10.3%)

Common (1% to 10%): Drowsiness, headache, faintness, syncope, vertigo

Uncommon (0.1% to 1%): Paresthesia, tinnitus

Rare (less than 0.1%): Narcolepsy worsened[Ref]

Other

Common (1% to 10%): Lack of energy, weakness, asthenia

Rare (less than 0.1%): Fever, pain

Frequency not reported: Malaise[Ref]

Gastrointestinal

Common (1% to 10%): Constipation, diarrhea, dry mouth, nausea, vomiting

Uncommon (0.1% to 1%): Abdominal discomfort and/or pain

Rare (less than 0.1%): Pancreatitis[Ref]

Respiratory

Common (1% to 10%): Dyspnea, nasal congestion, epistaxis[Ref]

Psychiatric

Common (1% to 10%): Depression, nervousness

Uncommon (0.1% to 1%): Insomnia

Rare (less than 0.1%): Hallucinations[Ref]

Ocular

Common (1% to 10%): Blurred vision, sclera reddened

Uncommon (0.1% to 1%): Eye pain

Frequency not reported: Pigmentary mottling, serious retinopathy, cataract development, cataract disappearance[Ref]

Genitourinary

Common (1% to 10%): Urinary frequency, impotence

Rare (less than 0.1%): Incontinence, priapism[Ref]

Dermatologic

Common (1% to 10%): Rash

Uncommon (0.1% to 1%): Diaphoresis, pruritus, urticaria

Rare (less than 0.1%): Alopecia, lichen planus[Ref]

Metabolic

Common (1% to 10%): Edema[Ref]

Musculoskeletal

Uncommon (0.1% to 1%): Arthralgia[Ref]

Immunologic

Rare (less than 0.1%): Allergic reaction, positive antinuclear antibody titer[Ref]

Endocrine

Rare (less than 0.1%): Gynecomastia[Ref]

Hepatic

Rare (less than 0.1%): Liver function abnormalities[Ref]

References

1. Cerner Multum, Inc. "Australian Product Information." O 0

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. "Product Information. Minipress (prazosin)." Pfizer US Pharmaceuticals, New York, NY.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

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