Pharmacy Services

5-alpha Reductase Inhibitors (5-ARIs)

June 13, 2011

The Warnings and Precautions section of the product labeling for 5-alpha reductase inhibitors (5-ARIs) has been amended to include an increased risk of high-grade prostate cancer. Finasteride (Proscar, Propecia) and dutasteride (Avodart) are the two 5-ARIs available in the US. Dulasteride is also available in combination with tamsulosin (Jalyn). Two large-scale randomized, controlled trials, the Prostate Cancer Prevention Trial (PCPT) and Reduction by Dutasteride of Prostate Cancer Events (REDUCE), showed an overall decrease in prostate cancer rates. New safety data from these trials found increased diagnoses of more aggressive prostate cancer with 5-ARI use.

Patients should be evaluated for other urological conditions, including prostate cancer, before beginning 5-ARI treatment. Report adverse events to the FDA MedWatch Safety Information and Adverse Event Reporting Program at or call 1-800-332-1088 to request a reporting form.

Additional information is available at the following links:

June 13, 2011; University of Utah, Drug Information Service. Copyright 2011, Drug Information Service, University of Utah, Salt Lake City, UT.