Alpha-blockers for benign prostatic hyperplasia


Generic Name Brand Name
alfuzosin hydrochloride Uroxatral
doxazosin mesylate Cardura
silodosin Rapaflo
tamsulosin hydrochloride Flomax
terazosin hydrochloride 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 men find a 4- to 6-point reduction in their American Urological Association (AUA) symptom index scores. Most men find this a significant improvement in their symptoms.1 Symptoms generally improve in 2 to 3 weeks.2

Using a combination of an alpha-blocker with a 5-alpha reductase inhibitor may help your symptoms more than either medicine alone.3, 4

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 and nasal congestion.

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

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

Some evidence suggests that alpha-blockers are more effective than finasteride in relieving symptoms.5

Long-acting forms of these medicines can be taken once a day, which may make them more convenient to take than finasteride.

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

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)(What is a PDF document?) to help you understand this medication.



  1. AUA Practice Guidelines Committee (2003). AUA guideline on management of benign prostatic hyperplasia (2003). Chapter 1: Diagnosis and treatment recommendations. Journal of Urology, 170(2, Part 1): 530–547.
  2. Paterson R, Goldenberg L (2001). Benign prostatic hyperplasia. In J Teichman, ed., 20 Common Problems in Urology, part 2, pp. 185–198. New York: McGraw-Hill.
  3. McConnell JD, et al. (2003). The long-term effect of doxazosin, finasteride, and combination therapy on the clinical progression of benign prostatic hyperplasia. New England Journal of Medicine, 349(25): 2387–2398.
  4. 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.
  5. Webber R (2006). Benign prostatic hyperplasia, search date May 2005. Online version of BMJ Clinical Evidence. Also available online:

Last Updated: March 24, 2008

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