Skip to Content

Flomax Side Effects

Generic Name: tamsulosin

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

In Summary

Common side effects of Flomax include: dizziness, nasal congestion, rhinitis, rhinorrhea, sinus congestion, and seasonal allergic rhinitis. Other side effects include: drowsiness. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to tamsulosin: oral capsule

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
  • Cough or hoarseness
  • fever or chills
  • lower back or side pain
  • painful or difficult urination
Less common
  • Chest pain
Rare
  • Dizziness or lightheadedness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fainting
  • feeling of constant movement of self or surroundings
  • painful or prolonged erection of the penis
  • sensation of spinning
Incidence not known
  • Blistering, peeling, or loosening of the skin
  • blurred vision
  • confusion
  • diarrhea
  • difficult or labored breathing
  • fast, pounding, or irregular heartbeat or pulse
  • itching
  • joint or muscle pain
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • sore throat
  • sores, ulcers, or white spots in the mouth or on the lips
  • sweating
  • tightness of the chest
  • unusual tiredness or weakness

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
  • Abnormal ejaculation
  • back pain
  • body aches or pain
  • congestion
  • headache
  • lack or loss of strength
  • sneezing
  • stuffy or runny nose
  • tender, swollen glands in the neck
  • trouble swallowing
  • voice changes
Less common
  • Decreased interest in sexual intercourse
  • decreased sexual drive or performance
  • drowsiness
  • inability to have or keep an erection
  • increased cough
  • loss in sexual ability, desire, drive, or performance
  • nausea
  • pain or tenderness around the eyes and cheekbones
  • sleepiness or unusual drowsiness
  • tooth disorder
  • trouble sleeping
Incidence not known
  • Constipation
  • hives or welts, skin rash
  • redness of the skin
  • vomiting

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
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 (up to 21.1%), dizziness (up to 17.1%)
Common (1% to 10%): Somnolence, insomnia
Rare (less than 0.1%): Syncope
Frequency not reported: Vertigo[Ref]

Genitourinary

Very common (10% or more): Abnormal ejaculation (up to 18.1%)
Common (1% to 10%): Ejaculation disorders, including retrograde ejaculation and ejaculation failure
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, decreased libido
Uncommon (0.1% to 1%): Fatigue[Ref]

Psychiatric

Common (1% to 10%): Insomnia[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. Flomax (tamsulosin)." Boehringer-Ingelheim, Ridgefield, CT.

Some side effects of Flomax may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

Hide