Drug finasteride can bring prostate relief

On Call

November 26, 1996|By Dr. Simeon Margolis | Dr. Simeon Margolis,SPECIAL TO THE SUN

For the past year I have awakened at least twice each night with the need to urinate, and I have also noticed increasingly difficulty in starting the flow of urine.

My doctor says I have benign prostatic hyperplasia and has recommended taking a drug, finasteride.

I recall that several months ago a newspaper article said this drug was ineffective.

What is your opinion?

Benign prostatic hyperplasia (BPH), an extremely common problem as men grow older, is caused by an enlarged prostate which obstructs the urethra and thus interferes with the flow of urine from the bladder through the urethra.

The increase in prostate size results from the overgrowth of two different types of cells -- epithelial cells and smooth muscle cells. The urethra can be blocked either by the bulk of the epithelial cells or by contractions of the smooth muscle cells.

The options for dealing with BPH are "watchful waiting" drugs, or a surgical procedure.

The rationale for watchful waiting is that some men have only mild to moderate symptoms which may progress very slowly over a matter of years. Two years of medications are available for men whose symptoms which may progress very slowly over a matter of years. Two types of medications are available for men whose symptoms are more troublesome: alpha-adrenergic antagonists and finasteride.

The two FDA-approved, adrenergic antagonists, terazosin (Hytrin) and doxazosin (Cardura), partially relieve the obstruction to urine flow by relaxing the smooth muscle cells.

Finasteride (Proscar) works by inhibiting an enzyme that converts the male sex hormone testosterone to dihydrotestosterone, the form of the hormone that promotes the growth of epithelial cells in the prostate.

As a result, finasteride partially overcomes the urethral blockage by shrinking the excessive number of prostatic epithelial cells.

Newspapers wrote stories about a report in an August issue of the New England Journal of Medicine, which described a study of a placebo, terazosin, finasteride, and a combination of the two in 1229 men with BPH. Compared to the placebo, terazosin improved symptoms and urine flow. Finasteride did not. Combining finasteride and terazosin was no more effective than terazosin alone.

These results might lead to the conclusion that finasteride is not a useful drug for BPH; but the authors of the study, as well as an accompanying editorial, pointed out that the men enrolled in this study had smaller degrees of prostate enlargement than those previously shown to benefit from finasteride.

Other studies have shown that terazosin is more effective in smaller prostates, where contraction of smooth muscle is the major problem, while finasteride is more likely to be effective in larger prostates which contain many more epithelial cells.

The bottom line is that either type of drug can help relieve symptoms; alpha adrenergic antagonists are probably the preferable choice for smaller prostates, while finasteride should be considered for larger ones.

When symptoms persist despite medications, a number of surgical procedures are effective in relieving the urethral obstruction.

Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine.

Pub Date: 11/26/96

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