Tamsulosin

Alpha-1A adrenoceptor antagonist, relatively selective for the prostate and bladder neck rather than vascular smooth muscle, so it relieves obstruction with less hypotension than older alpha blockers.

• Lower urinary tract symptoms from benign prostatic hyperplasia
• Medical expulsive therapy for ureteric stones

Bioavailability

~90% fasting, reduced by food

Half-life

9 to 13 h

Elimination

hepatic: CYP3A4 and CYP2D6; strong inhibitors raise exposure

Protein binding

~99%

• Dizziness and orthostatic hypotensioncommon
• Retrograde or absent ejaculationcommonCommon, distressing if unexpected, and reversible on stopping.
• Intraoperative floppy iris syndromeseriousComplicates cataract surgery and persists long after the drug is stopped.
• Rhinitiscommon
• PriapismseriousRare.

• Amlodipine / felodipine + Strong CYP3A4 inhibitors; grapefruit (felodipine)monitorMore vasodilation: flushing, edema, hypotension.

• Take it after the same meal each day.
• Get up slowly, especially at first.
• Tell your eye surgeon that you take or have taken this before any cataract operation, even years later.
• A change in ejaculation is common and reverses if the drug is stopped.

• Intraoperative floppy iris syndrome is the reason ophthalmologists ask about this drug specifically, and the patient rarely thinks to mention a urology tablet at an eye appointment.
• It relieves symptoms without changing the size of the prostate, so it does not alter the natural history; that is the 5-alpha reductase inhibitor's job.

• Tamsulosin product monograph (consult the current version for your market) (monograph)
• Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed. (reference-work)

Last reviewed 2026-08-16 · jurisdiction: global · drug information changes; verify against current references before practice use.