Evaluation of men on finasteride.

Finasteride, an orally active type II 5 alpha-reductase (5 alpha R) inhibitor, blocks conversion of testosterone (T) to dihydrotestosterone (DHT). The utility of finasteride in effectively managing benign prostatic hyperplasia has been documented. Use of the drug results in reduced prostate volume and serum levels. Patients receiving finasteride should be monitored with periodic digital-rectal examination (DRE) and serum PSA measurement. Patients with a sustained increase in serum PSA or an abnormal DRE require additional evaluation. There is no evidence that use of finasteride has an adverse effect on prostate cancer detection, if the drug's effect on serum PSA is recognized and accounted for.