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Alpha-Blockers for Benign Prostatic Hyperplasia


Generic NameBrand Name
alfuzosinUroxatral, Cardura, Rapaflo, Flomax, Hytrin
doxazosinUroxatral, Cardura, Rapaflo, Flomax, Hytrin
silodosinUroxatral, Cardura, Rapaflo, Flomax, Hytrin
tamsulosinUroxatral, Cardura, Rapaflo, Flomax, Hytrin
terazosinUroxatral, Cardura, Rapaflo, Flomax, Hytrin

How It Works

Alpha-blockers help treat benign prostatic hyperplasia (BPH) by relaxing smooth muscle tissue found in the prostate and the bladder neck. This allows urine to flow out of the bladder more easily.

These medicines usually are taken by mouth once or twice a day.

Why It Is Used

These medicines often are used by men who have moderate and bothersome symptoms of prostate enlargement and who want more than home treatment for their symptoms.

How Well It Works

Many BPH symptoms improve with alpha-blockers.1 For improving symptoms and urine flow, taking these medicines works better than taking no medicine. Men may have about a 4-point reduction in their American Urological Association (AUA) symptom index score.2

Symptoms typically improve in 2 to 3 weeks.

Using a combination of an alpha-blocker with a 5-alpha reductase inhibitor long-term may help your symptoms more than either medicine alone.3

Side Effects

Side effects vary with the medicine and the individual. Common minor side effects of alpha-blockers include:

  • Weakness or fatigue.
  • Lightheadedness, dizziness, or fainting when you stand up suddenly after sitting or lying down. This may occur if your blood pressure becomes low when you stand up suddenly (postural or orthostatic hypotension).
  • Headaches
  • Nasal congestion.

Alpha-blockers may cause ejaculation of semen into the bladder (retrograde ejaculation) instead of out through the penis. This is not harmful.

These side effects go away when the medicine is stopped.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

If you plan surgery for cataracts, make sure your doctors know that you take alpha-blockers. Some of these medicines have been linked to a problem called intra-operative floppy iris syndrome (IFIS).

Fewer side effects, especially low blood pressure when standing up suddenly, may occur if the drug is taken at bedtime.

Medicines used to treat erection problems, such as sildenafil (Viagra), vardenafil (Levitra), or tadalafil (Cialis), may make dizziness or lightheadedness worse.

Alpha-blockers are sometimes used to treat high blood pressure too. But for some people, an alpha-blocker does not help with their high blood pressure or is not a good choice for other reasons. So even if you are taking an alpha-blocker for your BPH symptoms, you may have to take another medicine to control your high blood pressure.

Complete the new medication information form (PDF)Click here to view a form.(What is a PDF document?) to help you understand this medication.



  1. AUA Practice Guidelines Committee (2010). AUA guideline on management of benign prostatic hyperplasia. Chapter 1: Guideline on the management of benign prostatic hyperplasia (BPH). Available online:

  2. McNicholas T, Kirby R (2011). Benign prostatic hyperplasia, search date July 2009. Online version of BMJ Clinical Evidence:

  3. Roehrborn CG, et al. (2008). The effects of dutasteride, tamsulosin and combination therapy on lower urinary tract symptoms in men with benign prostatic hyperplasia and prostatic enlargement: 2-year results from the CombAT study. Journal of Urology, 179(2): 616–621.


ByHealthwise Staff
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerJ. Curtis Nickel, MD, FRCSC - Urology
Last RevisedMarch 5, 2012

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