Alpha-Blockers for Benign Prostatic Hyperplasia

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Alpha-Blockers for Benign Prostatic Hyperplasia


Generic NameBrand Name

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 International Prostate Symptom Score (I-PSS). Most men find this a significant improvement in their symptoms.1 Symptoms generally improve in 2 to 3 weeks.

Using a combination of an alpha-blocker with a 5-alpha reductase inhibitor may help your symptoms more than either medicine alone.2

Side Effects

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

  • Weakness or fatigue.
  • Light-headedness, 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.

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

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. Available online:
  2. 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.


By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Christopher G. Wood, MD, FACS - Urology, Oncology
Last Revised June 25, 2010

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