Flutamide Disease Interactions

There have been postmarketing reports of hospitalization and rarely death due to liver failure in patients taking flutamide. Signs of hepatic injury included elevated serum transaminase levels, jaundice, hepatic encephalopathy and death related to acute hepatic failure. The hepatic injury was reversible after discontinuation of therapy in some patients. Approximately half of the reported cases occurred within the initial 3 months of treatment. Serum transaminase levels should be measured prior to starting treatment with flutamide. Flutamide is not recommended in patients whose ALT values exceed twice the upper limit of normal. Serum transaminase levels should then be measured monthly for the first 4 months of therapy, and periodically thereafter. Liver function tests also should be obtained at the first signs and symptoms suggestive of liver dysfunction, e.g., nausea, vomiting, abdominal pain, fatigue, anorexia, "flu-like" symptoms, hyperbilirubinuria, jaundice or right upper quadrant tenderness. If at any time, a patient has jaundice, or their ALT rises above 2 times the upper limit of normal, flutamide should be immediately discontinued with close follow-up of liver function tests. Flutamide should be administered with extreme caution in patients with or predisposed to compromised hepatic function, and it is contraindicated in patients with severe hepatic impairment.

Toxicity consistent with aniline exposure such as methemoglobinemia, hemolytic anemia, and cholestatic jaundice has been reported during flutamide therapy. Therapy with flutamide should be administered cautiously in patients with glucose-6-phosphate deficiency, hemoglobin M disease, and patients who smoke. Clinical monitoring of methemoglobin levels in susceptible individuals is recommended,