An in-depth report on the causes, diagnosis, treatment, and prevention of benign prostatic hyperplasia (BPH).
Enlarged prostate; BPH
The two primary drug classes used for BPH are:
Because these two types of drugs work in different ways, combinations of the two may control symptoms in select patients more effectively than either drug alone. The combination treatment may work best for patients with larger prostate glands and higher PSA readings. Many men, however, can control their condition with a single drug.
General Guidelines for Alpha-Blockers. Alpha-adrenergic antagonists, commonly called alpha-blockers, were originally used to treat high blood pressure. They are prescribed for BPH to relax smooth muscles in the prostate. The muscle cells in the prostate are stimulated by molecules called alpha adrenergic receptors. This can cause lower urinary tract symptoms.
Drugs that block these receptors relax the muscles in and around the prostate, increase urinary flow and improve symptoms, sometimes significantly. Improvement occurs within days to weeks. Because these drugs are short-acting, symptoms return very quickly once a man stops taking the medication. They neither affect PSA levels nor shrink the size of the prostate.
Alpha-blockers are prescribed for most men with BPH symptoms whose prostates are not significantly enlarged. Even men with moderately enlarged prostates might try alpha-blockers before more intense treatments because these drugs work fairly quickly, have no effect on sexual drive, and are the least expensive treatment for BPH. Some doctors now recommend alpha-blockers as first-line treatment for patients with moderate-to-severe symptoms.
These drugs are generally referred to as either nonselective or selective alpha-blockers. Nonselective alpha-blockers relax all smooth muscles in the body that surround blood vessels. Selective alpha-blockers target more specifically the smooth muscles of the prostate, but they can also affect other areas of the body, such as the eyes. Drugs in both categories are similar in effectiveness for reducing symptoms and improving urinary flow. There are some differences, however. Discuss with your doctor which alpha-blocker is best for your individual condition.
Brands. Nonselective alpha-blockers (also referred to as alpha-specific antagonists) for treatment of BPH include:
Selective alpha-blockers for treatment of BPH are:
Side Effects. Alpha-blockers can reduce blood pressure, which may cause dizziness lightheadedness, and fainting. Orthostatic hypotension, a sudden drop in blood pressure when standing, can occur and increases the risk of falling. Taking the medication close to bedtime can help reduce these side effects. Because of the reduced blood pressure side effect, do not take phosphodiesterase inhibitors [such as sildenafil (Viagra)] at the same time, at least without advice from a doctor.
Alpha-blockers can also cause headache, and stuffy or runny nose. Men may also experience a decreased ejaculate. (Erectile dysfunction is not a usual side effect of alpha-blockers, as it is with finasteride and dutasteride.)
A special concern for tamsulosin (Flomax), and other selective alpha-blockers, is that they are associated with a condition called intraoperative floppy iris syndrome (IFIS). IFIS is a loss of muscle tone in the iris that can cause complications during eye surgery. Patients who are planning cataract or other eye surgery should be sure to inform their doctors prior to the surgery. IFIS appears more likely to occur with the newer, selective alpha-blockers than non-selective alpha blockers.
The prostate gland contains an enzyme called 5 alpha-reductase that converts testosterone to another androgen called dihydrotestosterone. Finasteride (Proscar) and dutasteride (Avodart), known as 5-alpha-reductase inhibitors (5-ARIs), block this enzyme and thus reduce dihydrotestosterone in the prostate. This process helps to shrink an enlarged prostate and prevent future growth of the prostate. These drugs can also help prevent against urinary retention, and possibly reduce the need for future prostate surgery.
5-alpha-reductase inhibitors are not as effective as alpha-blockers in improving BPH and urinary tract symptoms, but they can help modestly reduce symptoms for some men. However, these drugs take several months before they have an effect so men may not notice any signs of improvement for 3 - 6 months. The 5 alpha-reductase inhibitors are most effective in reducing symptoms in men with enlarged prostates.
Side Effects. The main side effects of finasteride and dutasteride are erectile dysfunction, lowered sexual drive (libido), and reduced semen release during ejaculation. These side effects generally subside within a year or two of treatment. (A positive side effect of finasteride is possible reduction of hair loss related to male hormones and, in some cases, hair growth in men with mild-to-moderate male pattern baldness.)
There is ongoing debate on whether 5-alpha-reductase inhibitors can help prevent prostate cancer. The American Society of Clinical Oncology and American Urological Association recently issued guidelines concerning the pros and cons of 5-ARIs for prostate cancer prevention. Men who take these drugs for BPH should discuss this issue with their doctors. [For more information, see In-Depth Report #33: Prostate cancer.]
These drugs decrease prostate-specific antigen (PSA) levels, which may mask the presence of prostate cancer. To resolve this problem, doctors calculate PSA levels in men taking these drugs by doubling the PSA values. This doubling equation helps provide an accurate measurement
PDE5 Inhibitors. Phosphodiesterase-5 (PDE5) inhibitors are used to treat erectile dysfunction (ED). They include sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis). Because lower urinary tract symptoms (LUTS) and ED often occur together in older men, researchers are investigating whether PDE5 inhibitors may help improve BPH symptoms. Some studies indicate that sildenafil improves urinary symptoms in men who have both ED and LUTS. It is also being evaluated in combination with selective alpha-blocker drugs.
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