What Are the Dangers of Finasteride With Testosterone?

Finasteride, also sold under the brand name Proscar, is a drug marketed for treatment of benign prostate enlargement. This drug is meant to reduce the risk of urinary retention and improve the patient's chances of a non-surgical recovery. Under the name Propecia, the drug has also been used to treat male pattern hair loss. The drug does have some effects on testosterone levels, however, and may cause unpleasant or dangerous side effects.

Sexual Function

• Finasteride treatment leads to an increase in blood testosterone, a male hormone which affects sexual function and libido. Men taking this drug should be aware that they may suffer from impotence and decreased libido, problems ejaculating, and abnormal sexual function. These symptoms alone are not dangerous, but poor sexual function may put a strain on existing relationships and contribute to depression and mood disorders.

Breasts

• According to RxList, a significant number of men experience enlargement of breast tissue when using finasteride. Changes in hormone levels may cause abnormal growth, and .4 percent of men treated with the drug suffered from breast growth in the first year, compared to .1 percent of men not using the drug. This number climbed to 1.8 percent in years two through four, compared to 1.1 percent in the control group. Men may also experience soreness and tenderness of breast tissue in the chest. A small number of men--four patients out of around 1,500--reported developing breast cancer in relation to the therapy.

Blood Pressure

• Hormone changes caused by finasteride treatment may also cause problems with blood flow. This may contribute to the erection difficulty many men have. It can also lead to postural hypotension--low blood pressure which occurs when a person moves from one position to another. Men who suffer this side effect may feel dizzy or faint. In rare cases, low blood pressure can cause a dangerous fall.