Medications

Selective Alpha-Blockers. Tamsulosin (Flomax) is the only selective alpha-blocker (sometimes called alpha1A-urospecific antagonists) approved to date. Naftopidil is a similar drug under investigation. These drugs target receptors that affect only the smooth muscles of the prostate. Tamsulosin appears to be similar in effectiveness to the nonselective alpha-blockers. It is not clear if it reduces long-term complications of BPH.

Selective alpha-blockers appear to be very safe, even for years. Side effects are minimal. Most common ones include nasal congestion. The risk for low blood pressure and dizziness is lower than with the nonselective alpha-blockers. They may pose a higher risk for problems in ejaculation than nonselective alpha-blockers, but do not appear to cause impotence or reduce sexual drive as finasteride does. These drugs can interact with certain medications, including calcium channel blockers (particularly verapamil).

Finasteride and Other 5-Alpha-Reductase Inhibitors

Specific Benefits. 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 a 5-alpha-reductase inhibitors, block this enzyme and thus reduce dihydrotestosterone in the prostate.

Finasteride is not as effective as alpha-blockers in improving BPH and urinary tract symptoms, but it can be helpful. Follow-up studies have reported that the drug is safe and effective over the long-term. The 5 alpha-reductase inhibitors are perhaps most effective in reducing symptoms in men with large prostates. (Men with larger prostates and high PSA values may also benefit from combination therapy of finasteride and the alpha-blocker doxazosin.) In such cases, studies on finasteride also suggest it reduces the risk of acute urinary retention and the need for surgery. It also helps control bleeding in the urine that is related to BPH. A side benefit of finasteride is reduction of hair loss related to male hormones and in some cases hair growth in men with mild to moderate male pattern baldness.