Health and Prostate

Glossary

Adrenergic: Relating to nerve cells of the autonomic nervous system. Alpha- and beta-adrenergic receptors receive chemical signals controlling autonomic functions. Adrenergic blockers prevent signals from being received by that class of receptor.

Androgen: Any male sex hormone, such as testosterone.

Prostatectomy: Surgery to reduce the size of the prostate gland.

Benign prostatic hyperplasia (BPH) most often manifests as obstructed urinary flow and irritative urinary symptoms. Treatments are aimed primarily at relieving such symptoms. Prostatectomy and watchful waiting are the long-accepted therapies. Two types of drug have recently been added to the therapeutic options for BPH and have been demonstrated to be safe and effective in previous studies. They have not, however, ever been compared against one another in a blinded study.

This study enrolled 1,229 men with symptoms of BPH who were attending outpatient clinics at participating Veterans’ Affairs medical centres in the United States between 1992 and 1994. They were between 45 and 80 years old, had symptom scores on the American Urological Association Symptom Index of at least eight, and a mean peak urinary flow rate of between 4 ml and 15 ml per second. After undergoing physical and laboratory exams and receiving placebo for four weeks, the men were assigned to one of four drug regimens. They received either placebo, terazosin (Hytrin) (10 mg/day), finasteride (Proscar) (5 mg/day) or a combination of the two drugs for 52 weeks.

Participants were examined at regular intervals over the course of the study, and pills were counted to assess compliance with the prescribed drug regimen. Men receiving terazosin (or its placebo) could have the dose reduced to 5 mg/day if they experienced ill effects at 10 mg. Side effects were inquired about at each follow-up visit. Patients receiving finasteride had significantly more problems with impotence and decreased sex drive, while those on terazosin reported dizziness more often and those receiving the combination reported more problems with ejaculation. In all, 18% of the patients discontinued their treatment before the end of the study for various reasons. However, only 4.8% of the finasteride group, 5.9% of the terazosin group and 7.8% of the combination group stopped taking their medication due to adverse effects — as well as 1.6% of those on placebo.

At the end of the study period, test results and symptom scores were compared to those recorded at the outset of the study, and the changes noted in each group were compared against each other. Mean symptom scores were decreased almost twice as much in the terazosin and combination groups as in the finasteride group, with the placebo group having an even smaller reduction. Mean increases in peak urinary flow rates were 1.4 ml/second for placebo, 1.6 ml/sec for finasteride, 2.7 ml/sec for terazosin and 3.2 ml/sec for the combination group. Prostate volume was found to increase by 0.6 cm3 in the placebo group and 0.5 cm3 in the terazosin group, while decreasing by 6.1 cm3 in the finasteride group and by 7.0 cm3 in the combination group. Prostate-specific antigen (PSA, a common measure of prostate health) levels were more improved in the terazosin and combination groups.

Given that the primary goal of treatment is to alleviate benign prostatic hyperplasia (BPH) symptoms, the authors concluded that the comparison of the two drugs clearly favoured terazosin. Terazosin produced significantly better improvements in symptom scores and urinary flow rates. As well, there appeared to be no advantage to taking finasteride and terazosin in combination, as results were not significantly better than in men receiving terazosin alone.

The finding that finasteride was no better than placebo contradicts other studies that looked at finasteride alone. The authors suggest that this may be due to the fact that different indexes of symptom scores were used, or that participants in the other studies had a higher degree of prostate enlargement at the outset. A longer study period may also have affected the outcome. As is so often the case with medical research, more studies need to be done so that all the possible variables can be accounted for before there are definitive answers.