Prostate Cancer Home > Flutamide Side Effects
Common Side EffectsFlutamide has been studied thoroughly in clinical trials. In these studies, the side effects that occurred in a group of people taking flutamide were carefully documented and compared to those that occurred in another group of people receiving either a different treatment or a placebo (a "sugar pill" with no active ingredients). As a result, it was possible to see what side effects occurred, how often they appeared, and how they compared to the other groups.
It should be noted that everyone also received a gonadotropin-releasing hormone (GnRH) agonist in the clinical trials. Therefore, it can be difficult to know for certain which side effects are from flutamide and which are a result of the GnRH agonist.
In clinical studies, the most commonly reported reactions included:
- Hot flashes -- in up to 61 percent of people
- Loss of libido (loss of sex drive) -- up to 36 percent
- Impotence (erectile dysfunction, or ED) -- up to 33 percent
- Diarrhea -- up to 12 percent
- Nausea and vomiting -- up to 11 percent
- Enlarged breasts -- up to 9 percent
- Gastrointestinal (GI) problems -- up to 6 percent
- Decrease in red blood cells (anemia) -- up to 6 percent.
Other common side effects (occurring in 1 to percent of people) included:
- Decreased appetite
- Swelling (edema) of the hands, legs, ankles, or feet
- Low blood platelets or white blood cells
- High blood pressure (hypertension)
- Mood problems, such as anxiety, nervousness, or depression.
Flutamide has also been reported to cause urine discoloration. The urine may appear orange-yellow or yellow-green in color.