Two of my patients are older men (aged 62 years and 68 years) who have benign prostatic hyperplasia; their prostates are soft and nontender. Recent prostate-specific antigen (PSA) measurements revealed elevated levels-from 3.5 to 4.4 ng/mL in the 62-year-old man and from 4.2 to 5.8 ng/mL in the 68-year-old man. Both patients had taken sildenafil(Drug information on sildenafil) and had sexual intercourse the day before the examination. Could the elevations in their PSA levels be an effect of sildenafil? If so, how long does this effect persist?
—Leonard B. Beller, MD
PSA levels can vary throughout the day. There is no evidence that sildenafil, without sexual intercourse, alters these levels.
However, the results of a number of trials suggest that intercourse may affect PSA values. My colleagues and I conducted a study that showed intercourse had no effect in men with normal baseline levels but was associated with increased PSA values in men who had an elevated baseline measurement.1 I have also found that bicycle riding and digital rectal examinations do not affect PSA levels.2,3
Therefore, I believe the degree of change seen in your patients warrants further investigation. The normal PSA level for men of this age is less than 3 ng/mL.—E. David Crawford, MD
Professor of Surgery and Radiation Oncology
University of Colorado
1. Stenner J, Hathaus K, MacKenzie SH, Crawford ED. The effect of ejaculation on prostate specific antigen in a prostate cancer screening population. Urology. 1998;51:455-459.
2. Safford HR, Crawford ED, MacKenzie SH, Capriola M. The effect of bicycle riding on serum prostate specific antigen levels. J Urol. 1996;156:103-105.
3. Crawford ED, Schutz MJ, Clefan S, et al. The effect of digital rectal examination on prostate specific antigen levels. JAMA. 1992;267:2227-2228.