Propecia and Proscar Possible Association with Male Breast Cancer
The labels for Propecia and Proscar, as well as generic forms of finasteride, are being updated in Canada because of a possible association with male breast cancer. According to an alert from Health Canada, male breast cancer has been reported in a small number of patients worldwide with both the 1 mg (Propecia) and 5 mg (Proscar) formulations of finasteride, though most have been associated with the 5mg formulation.
Propecia (used to treat male pattern baldness) and Proscar (used to treat non-cancerous enlarged prostate) are part of a class of drugs known as 5-alpha reductase inhibitors, or 5-ARIs. Other drugs in this class include Avodart (dutasteride) and Jalyn (dutasteride and tamsulosin).
According to the Health Canada alert, the label for Propecia, Proscar and several of the generic finasteride products has already been updated to include information on the potential risk of male breast cancer. Updates to the remaining generic drugs will follow, the agency said.
Based on the currently available evidence, Health Canada said it is not known with certainty whether finasteride can cause breast cancer, nor can this possibility be ruled out at this point in time, Health Canada said. However, the agency is advising men who take Proscar, Propecia and other finasteride products to contact their doctor if they experience including breast enlargement, lumps, tenderness, pain or nipple discharge.
In June, the U.S. Food & Drug Administration (FDA) also announced a labeling change for this class of drugs after studies showed that while 5-ARIs reduced the overall risk of prostate cancer, they increased the risk that a user would develop a more serious type of tumor known as high-grade prostate cancer. The new information was added to the “Warning and Precautions” section of the label for all 5-ARIs sold in the U.S.