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Flomax Side Effects

Generic name: tamsulosin

Medically reviewed by Drugs.com. Last updated on May 30, 2023.

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

Applies to tamsulosin: oral capsule.

Serious side effects of Flomax

Along with its needed effects, tamsulosin (the active ingredient contained in Flomax) 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 tamsulosin:

More common

Less common

Rare

Incidence not known

Other side effects of Flomax

Some side effects of tamsulosin 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

Incidence not known

For Healthcare Professionals

Applies to tamsulosin: oral capsule.

General

The most commonly reported side effects were abnormal ejaculation, influenza-like symptoms, headache, dizziness, and rhinitis.[Ref]

Immunologic

Very common (10% or more): Infection (up to 10.8%)

Uncommon (0.1% to 1%): Flu like symptoms

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

Cardiovascular

Common (1% to 10%): Chest pain

Uncommon (0.1% to 1%): Orthostatic hypotension

Rare (less than 0.1%): Syncope

Postmarketing reports: Palpitations, hypotension, atrial fibrillation, arrhythmia, tachycardia[Ref]

Dermatologic

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

Postmarketing reports: Stevens-Johnson syndrome, erythema multiforme, exfoliative dermatitis, skin desquamation[Ref]

Nervous system

Very common (10% or more): Headache (21%), dizziness (17%)

Common (1% to 10%): Somnolence, insomnia

Frequency not reported: Vertigo[Ref]

Genitourinary

Very common (10% or more): Abnormal ejaculation (18%)

Common (1% to 10%): Ejaculation disorders (e.g., retrograde ejaculation, ejaculation failure), decreased libido

Uncommon (0.1% to 1%): Semen volume reduced, ejaculation delayed

Postmarketing reports: Priapism[Ref]

Respiratory

Very common (10% or more): Rhinitis (up to 17.9%)

Common (1% to 10%): Pharyngitis, Increased cough, sinusitis

Uncommon (0.1% to 1%): Nasal congestion

Postmarketing reports: Dyspnea, epistaxis[Ref]

Musculoskeletal

Common (1% to 10%): Back pain[Ref]

Gastrointestinal

Common (1% to 10%): Diarrhea, nausea, tooth disorder

Uncommon (0.1% to 1%): Constipation, vomiting

Frequency not reported: Dry mouth[Ref]

Ocular

Common (1% to 10%): Blurred vision

Postmarketing reports: Visual impairment, intraoperative Floppy Iris Syndrome (IFIS)[Ref]

Other

Common (1% to 10%): Asthenia

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

Psychiatric

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

References

1. Product Information. Flomax (tamsulosin). Boehringer-Ingelheim. 2001;PROD.

2. Cerner Multum, Inc. UK Summary of Product Characteristics.

3. Cerner Multum, Inc. Australian Product Information.

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.