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Minipress Side Effects

Generic name: prazosin

Medically reviewed by Last updated on Mar 29, 2022.

Note: This document contains side effect information about prazosin. Some of the dosage forms listed on this page may not apply to the brand name Minipress.


Common side effects of Minipress 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 capsules

Side effects include:

Dizziness, lightheadedness, headache, drowsiness, lack of energy, weakness, palpitation, nausea.

For Healthcare Professionals

Applies to prazosin: compounding powder, oral capsule


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


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]


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

Rare (less than 0.1%): Fever, pain

Frequency not reported: Malaise[Ref]


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]


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


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

Uncommon (0.1% to 1%): Insomnia

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


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]


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

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


Common (1% to 10%): Rash

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

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


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


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


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


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


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


1. "Product Information. Minipress (prazosin)." Pfizer U.S. Pharmaceuticals (2001):

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

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

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.