Tamsulosin is a generic prescription drug that relieves urination retention in men with an enlarged prostate. As an alpha blocker, tamsulosin relaxes the smooth muscle cells in the prostate and bladder neck, allowing patients to more completely empty the bladder when urinating. Doses are taken once daily, one-half hour following the same meal each day.
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Flomax
Tamsulosin HCl
Treats the urinary symptoms of benign prostatic hyperplasia (enlarged prostate).
Alpha blocker
Capsule
By mouth
Tamsulosin is FDA-approved to treat men with urinary retention caused by an enlarged prostate. Doctors sometimes use it off-label to treat urinary retention in women or to help patients pass kidney stones.
Capsule
0.4 mg
For the urinary symptoms of benign prostatic hyperplasia (enlarged prostate): 0.4–0.8 mg taken once per day, ½ hour after the same meal each day
Tamsulosin HCl
0.4mg capsule
Follow all the prescriber’s instructions.
Please read the Patient Information sheet before taking this medicine.
Take only one dose daily.
Take each dose 30 minutes after the same meal each day.
For instance, if you take the first dose after breakfast, take all other daily doses after breakfast.
Swallow the capsule whole. Do not crush, chew, or open it.
Store tamsulosin capsules at room temperature.
If you miss a dose, take it as soon as you remember.
If it’s the next day, skip the missed dose. Take the next dose when you usually would.
If several doses in a row are missed, call the prescriber for advice before taking another dose.
Do not take extra medicine to make up for a missed dose.
This medicine is not right for everyone.
Do not use it if you have had an allergic reaction to tamsulosin.
Inform other healthcare professionals treating you that you are taking tamsulosin.
The prescriber needs regular visits to check your progress and the effects of tamsulosin therapy. Keep all appointments.
Before starting tamsulosin, make sure the prescriber knows your medical history and current medical problems, particularly:
Kidney problems
Liver problems
A history of low blood pressure
Sulfa drug allergies
Tell the healthcare provider if you’ve been diagnosed as a poor CYP2D6 metabolizer. This is a genetic condition that affects your ability to break down certain drugs like tamsulosin.
Tamsulosin can cause problems during cataract or glaucoma surgery. Tell the ophthalmologist before the procedure that you’re using tamsulosin.
Tamsulosin can cause dizziness, lightheadedness, or fainting when standing up or changing position.
To manage this, stand or sit up slowly.
Sit back down if you feel dizzy until the lightheadedness passes.
Avoid driving or other potentially hazardous activities until you know how the medicine affects you.
In rare cases, tamsulosin can cause persistent, painful erections. Get immediate medical attention when this happens.
Tell the prescriber about all the drugs and supplements you regularly take. In particular, tamsulosin can cause problems in people taking:
Other alpha blockers
Erectile dysfunction medications
Blood pressure medications
HIV/AIDS drugs called protease inhibitors
Cimetidine, erythromycin, itraconazole, ketoconazole, paroxetine, terbinafine
Tell other healthcare providers you are using tamsulosin before they prescribe new medications.
Serious side effects
Talk to a doctor if you notice any signs or symptoms of a possible serious side effect, including:
Lightheadedness, dizziness, fainting
Painful, prolonged erection of your penis
Blistering, peeling, red skin rash
Allergic reaction: Itching, skin rash, hives, swelling in your face, mouth, or throat, chest tightness, trouble breathing, trouble swallowing
Less serious side effects
Headache
Problems with ejaculation
Runny or stuffy nose
Dizziness
Infection
Alpha blockers for nephrolithiasis, American Family Physician
Female urinary retention, StatPearls
Flomax drug summary, Prescriber’s Digital Reference (PDR)
Tamsulosin hydrochloride capsule prescribing information, DailyMed (NIH National Library of Medicine)
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Blog articles are not medical advice. They are intended for general informational purposes and are not meant to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. If you think you may have a medical emergency, immediately call your physician or dial 911.
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© 2025 SingleCare Administrators. All rights reserved