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Medical and Pharmacy Editor:

Brand Name: Flomax

Generic Name: Tamsulosin

Drug Class: BPH, Alpha Blockers; Alpha1 Blockers

What Is Tamsulosin and How Does It Work?

Tamsulosin is used by men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia-BPH). It does not shrink the prostate, but it works by relaxing the muscles in the prostate and the bladder. This helps to relieve symptoms of BPH such as difficulty in beginning the flow of urine, weak stream, and the need to urinate often or urgently (including during the middle of the night).

Tamsulosin belongs to a class of drugs known as alpha-blockers.

Do not use this medication to treat high blood pressure.

Tamsulosin is available under the following different brand names: Flomax.

Dosage of Tamsulosin:

Dosage Forms and Strengths


  • 0.4mg

Dosing Consideraations – Should be Given as Follows:

Benign Prostatic Hypertrophy

  • 0.4 mg orally once daily, 30 minutes after same meal each day; if response is inadequate after 2-4 weeks, may be increased to 0.8 mg once daily; if therapy is interrupted, should be resumed at 0.4 mg once daily

Bladder Outlet Obstruction

Relief of symptoms

  • 0.4 mg orally once daily

Ureteral Stones

Facilitation of stone expulsion

  • 0.4 mg orally once daily; discontinued after successful expulsion (average, 1-2 weeks)

Dosing Modifications

Renal impairment

  • CrCl 10 mL/min or greater: Dosage adjustment not necessary
  • CrCl less than 10 mL/min: Not studied

Hepatic impairment

  • Mild to moderate: Dosage adjustment not necessary
  • Severe: Not studied
  • Pediatric: Safety and efficacy not established

    Medically Reviewed by a Doctor on 5/31/2017

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