Background. The nonsteroidal antiandrogenic drug flutamide is a safe and generally well-tolerated drug used for the treatment of prostate cancer and female hyperandrogenism.

Case. We describe the case of a 26-year-old girl with amenorrhea and severe hirsutism who was treated with flutamide 250 mg/day and developed liver toxicity during therapy.

Results. Other causes of liver toxicity were appropriately ruled out. The use of the standard Council for International Organization of Medical Sciences (CIOMS) scale and the Maria & Vitorino (M&V) scale indicated a highly probable relationship between the development of liver toxicity and flutamide therapy. Severe liver dysfunction has been rarely documented in women with hirsutism treated with flutamide, even though cases of fulminant liver failure have been described. The mechanisms responsible for the occurrence of hepatotoxicity during treatment with flutamide are unknown, but mitochondrial dysfunction seems to be implicated.

Conclusion. The potential of flutamide to act as a potent hepatotoxin should be kept in mind when treatment with this drug is being planned. This case reminds us that patients who are receiving flutamide should be regularly monitored for liver function. If drug-induced liver injury is suspected, flutamide must be discontinued promptly to avoid progression of liver injury.