PSA levels could drop with commonly prescribed drugs

Physicians should be more attuned to what medications their male patients are taking because commonly prescribed drugs could decrease prostate-specific antigen levels, the author of a new study says.

The study, published online Aug. 2 in the Journal of Clinical Oncology, indicates that patients using nonsteroidal anti-inflammatory drugs, statins and thiazide diuretics have lower serum total PSA levels than those who do not take the medications. The difference in levels between the two studied groups of men increased with prolonged drug use (link).

Steven L. Chang, MD, a urologist at Brigham and Women's Hospital in Boston and the lead author of the study, said more research is needed to determine whether a medication-adjusted PSA threshold should be implemented to ensure that prostate cancer diagnoses are not delayed or missed in men who take these drugs.

The study's findings "could have a significant impact on screening and the effect of the PSA. ... But all we can say at this time is that physicians should be mindful of these three medications. ... They should be aware of the data and look at levels through that filter," said J. Brantley Thrasher, MD, professor and chair of the Dept. of Urology at the University of Kansas Medical Center in Kansas City, Kan. He also is a spokesman on prostate cancer for the American Urological Assn.

In 2006, more than 203,000 men were diagnosed with prostate cancer and 28,372 died of the disease, according to the Centers for Disease Control and Prevention's most recent data. It is the most commonly diagnosed cancer among men in the U.S.

Researchers examined the medication use and PSA levels of 1,864 men 40 and older who participated in the National Health and Nutrition Examination Survey between 2003 and 2006. Participants did not have prostate cancer.

Using statistical analysis, researchers determined the impact of the 10 most commonly prescribed medication classes on patients' PSA levels. They found that after five years of use, men on nonsteroidal anti-inflammatories had PSA levels that were 6% lower than those of men who were not taking the drugs. Among patients on statins, levels were 13% lower. Men on thiazide diuretics had levels 26% lower.

The lowest PSA levels were associated with combined use of statins and thiazide diuretics. Men taking these two drugs for five years had levels 36% lower than patients not taking both drugs.

The study "raises many questions about the interpretation of PSA in individuals taking these medications," Dr. Chang said. "But the true implication is pending further evaluation of why there is a difference" in PSA levels between men who use the drugs and those who do not.