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Benign Prostatic Hyperplasia (BPH)

(Benign Prostatic Hypertrophy)


Gerald L. Andriole

, MD, Barnes-Jewish Hospital, Washington University School of Medicine

Last full review/revision Nov 2020| Content last modified Nov 2020

Benign prostatic hyperplasia (BPH) is a noncancerous (benign) enlargement of the prostate gland that can make urination difficult.

  • The prostate gland enlarges as men age.
  • Men may have difficulty urinating and feel the need to urinate more often and more urgently.
  • Usually, the diagnosis is based on results of a rectal examination, but a blood sample may be taken to check for prostate cancer.
  • If needed, drugs to relax the muscles of the prostate and bladder (such as terazosin) or to shrink the prostate (such as finasteride) are used, but sometimes surgery is necessary.

The prostate is a gland in men that lies just under the bladder and surrounds the urethra. The gland, along with the nearby seminal vesicles, produces much of the fluid that makes up a man's ejaculate (semen). The prostate is walnut-sized in young men but enlarges with age. As the prostate enlarges, it gradually compresses the urethra and blocks the flow of urine (urinary obstruction). When men with BPH urinate, the bladder may not empty completely. Consequently, urine stagnates in the bladder, making men susceptible to urinary tract infections (UTIs) and bladder stones. Prolonged obstruction can weaken the bladder and ultimately damage the kidneys.

Male Reproductive Organs

Male Reproductive Organs

Causes of BPH

Benign prostatic hyperplasia (BPH) becomes increasingly common as men age, especially after age 50. The precise cause is not known but probably involves changes caused by hormones, including testosterone and especially dihydrotestosterone (a hormone related to testosterone).

Drugs such as over-the-counter antihistamines and nasal decongestants can increase resistance to the flow of urine or reduce the bladder’s ability to contract, causing temporary blockage of urine flow out of the bladder in men with BPH.

Symptoms of BPH

Benign prostatic hyperplasia (BPH) first causes symptoms when the enlarged prostate begins to block the flow of urine. Health care providers sometimes use the term lower urinary tract symptoms to describe the combination of symptoms that BPH can cause. At first, men may have difficulty starting urination. Urination may also feel incomplete. Because the bladder does not empty completely, men have to urinate more frequently, often at night (nocturia). Also, the need to urinate may become more urgent. The volume and force of the urinary flow may diminish noticeably, and urine may dribble at the end of urination.

The lower urinary tract symptoms of benign prostatic hyperplasia (BPH) can also be caused by other disorders, including infection, prostate cancer, and overactive bladder. 


Other problems can develop from an enlarged prostate, but these problems affect only a small number of men with BPH. Obstruction of urine flow with retention of some urine in the bladder may increase the pressure in the bladder and limit the flow of urine from the kidneys, putting increased stress on the kidneys. This increased pressure may impede kidney function, although the effect is usually temporary if the obstruction is relieved early.

If obstruction is prolonged, the bladder may overstretch, causing overflow incontinence. As the bladder stretches, small veins in the bladder and urethra also stretch. These veins sometimes burst when men strain to urinate, causing blood to enter the urine.

Urine flow out of the bladder can be blocked (urinary retention) completely, making urination impossible and usually leading to a full feeling and severe pain in the lower abdomen. However, occasionally urinary retention can occur with few or even no symptoms until retention is very severe. Urinary retention can be triggered by the following conditions:

  • Being immobile (for example, when put on bed rest)
  • Being exposed to cold
  • Delaying urination for a long time
  • Using certain anesthetics, alcohol, amphetamines, cocaine, opioids, or drugs with anticholinergic effects (see sidebar Anticholinergic: What Does It Mean?) such as antihistamines and decongestants and some antidepressants

What Happens When the Prostate Gland Enlarges?

In benign prostatic hyperplasia, the prostate gland enlarges. Normally the size of a walnut, the prostate gland may become as large as a tennis ball. The enlarging prostate gland squeezes the urethra, which carries urine out of the body. As a result, urine may flow through more slowly, or less urine may flow through.

What Happens When the Prostate Gland Enlarges?

Diagnosis of BPH

  • Rectal examination
  • Sometimes uroflowmetry
  • Sometimes biopsy or magnetic resonance imaging (MRI)

By feeling the prostate during a rectal examination, doctors can usually determine if it is enlarged. Doctors insert a gloved and lubricated finger into the rectum. The prostate can be felt just in front of the rectum. A prostate affected by benign prostatic hyperplasia (BPH) feels enlarged, symmetrical, and smooth but is not painful to the touch. Firm or hard areas may indicate prostate cancer.

A urine sample should be examined (urinalysis) to make sure there is no infection or bleeding. When an examination reveals an enlarged prostate or a man has symptoms of urine blockage, doctors typically also do a test to measure the level of prostate-specific antigen (PSA) in the blood. The PSA level can be elevated in men with BPH and also in men with prostate cancer. If the PSA level is elevated or the prostate is hard or lumpy to the touch, other tests may then be required to determine if cancer is present.

Men who have symptoms of urine blockage may be asked to urinate into a device that measures the volume and rate of urine flow (a test called uroflowmetry). Immediately after the uroflowmetry, doctors do a bladder ultrasound examination to determine how completely the bladder has emptied. Both these tests help diagnose the presence and severity of urine blockage.

If doctors suspect prostate cancer, they may use transrectal ultrasonography (TRUS) to help identify an appropriate tissue sample from the prostate for biopsy. In men with high or increasing PSA levels, a newer technology called multiparametric MRI may be used to enhance diagnosis and treatment of BPH. Occasionally, cystoscopy is done to exclude other causes of urine blockage, such as a urethral stricture, or to help plan the best approach for surgery.

Treatment of BPH

  • Drugs
  • Sometimes surgery
  • Treatment of infection or urinary retention before treatment of benign prostatic hyperplasia (BPH)

Treatment is not necessary unless BPH causes especially bothersome symptoms or complications (such as urinary tract infections, impaired kidney function, blood in the urine, stones, or urinary retention). Drugs that can worsen symptoms, such as opioids, drugs with anticholinergic effects (for example, many antihistamines and some antidepressants), and drugs called sympathomimetics (including some common cold remedies) should be stopped when possible.


Drugs are usually tried first. Alpha-adrenergic blockers (such as terazosin, doxazosin, tamsulosin, alfuzosin, or silodosin) relax certain muscles of the prostate and bladder outlet and may improve the flow of urine. Some drugs (such as finasteride and dutasteride) may block the effects of the male hormones responsible for the prostate’s growth, shrinking the prostate and preventing or delaying the need for surgery or other treatments. However, finasteride and dutasteride may need to be taken for 3 months or more before symptoms are relieved. Also, some men who take finasteride or dutasteride never experience relief of their symptoms. Some men are treated with an alpha-adrenergic blocker plus either finasteride or dutasteride.

Many over-the-counter complementary and alternative products are promoted for treatment of BPH, but none, including saw palmetto, has been shown to be effective.

Men who also have erectile dysfunction (impotence) may be treated with daily tadalafil because this drug may help relieve both erectile dysfunction and BPH.


If drugs are ineffective, surgery can be done. Surgery offers the greatest relief of symptoms but may cause complications. The most common surgical procedure is transurethral resection of the prostate (TURP), in which a doctor passes an endoscope (a viewing tube) through the urethra. Attached to the endoscope is a surgical instrument that is used to remove part of the prostate. Sometimes a laser is used during TURP. TURP does not involve an incision of the skin.

TURP can lead to such complications as infection and bleeding. Also, permanent urinary incontinence develops in about 1 to 3% of men. The procedure also can cause permanent erectile dysfunction. How often erectile dysfunction occurs is not known. Some experts estimate as many as 35% of men who undergo TURP develop erectile dysfunction, but most estimates are lower (5 to 10%). After TURP, some men ejaculate semen into the bladder instead of out through the urethra (called retrograde ejaculation). However, technical advances have greatly improved the safety of TURP.

About 10% of men undergoing TURP need the procedure repeated within 10 years because the prostate continues to grow. If the prostate is very large, TURP may not be possible, and doctors may need to do a more invasive surgical procedure through an incision in the abdomen.

Various alternative surgical treatments offer less rapid symptom relief than TURP. However, the risk of complications is lower with these treatments. Most of these procedures are done with instruments inserted through the urethra. These treatments destroy prostate tissue with

  • Microwave heat (transurethral microwave thermotherapy or hyperthermia)
  • A needle (transurethral needle ablation)
  • Radiofrequency waves (radiofrequency vaporization)
  • Ultrasound (high-intensity focused ultrasound; not approved in the United States for treatment of BPH)
  • Electric vaporization (transurethral electrovaporization)
  • Lasers (laser therapy)
  • Newer treatments, such as injection of hot water under pressure into the prostate or insertion of devices through the penis to help support the internal portion of the urethra


Problems resulting from urine blockage may need treatment before BPH is definitively treated. Urinary retention can be treated by draining the bladder by means of a catheter inserted through the urethra. Infections can be treated with antibiotics.

Drugs Mentioned In This Article

Generic Name Select Brand Names
dutasteride AVODART
tamsulosin FLOMAX
alfuzosin UROXATRAL
silodosin Silodosin
doxazosin CARDURA
tadalafil CIALIS
terazosin HYTRIN

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