Possible Side Effects
Clinical studies showed that side effects were uncommon and did not affect most men.
In general use, the following side effects have been reported:
You should promptly report to your doctor any changes in your breasts such as lumps, pain, or nipple discharge. Tell your doctor about these or any other unusual side effects.
A small number of men had sexual side effects, with each occurring in less than 2% of men. These include:
These side effects went away in men who stopped taking Propecia because of them. In addition, these side effects decreased to 0.3% of men or less by the fifth year of treatment.
In 3 controlled clinical trials for Propecia of 12-month duration, 1.4% of patients who took Propecia were discontinued due to adverse experiences that were considered to be possibly, probably, or definitely drug related. 1.6% of patients who took a sugar pill (placebo) were discontinued due to adverse experiences.
Propecia can affect a blood test called PSA (prostate-specific antigen) for the screening of prostate cancer. If you have a PSA test done, tell your doctor that you are taking Propecia.