In July 2024, the U.S. Food and Drug Administration approved Felanorm [FEEL-ah-norm], the first generic form of methimazole for treating hyperthyroidism in cats.
Hyperthyroidism is common in cats over eight years old. It causes the body’s metabolism to rev up, resulting in weight loss in spite of a good appetite. Other signs can include increased drinking and urinating, vomiting, diarrhea and a poor coat.
Methimazole products approved for people are not safe and effective in cats. For now, Felanorm is one of two oral methimazole drugs approved for felines. The other is Felimazole [fell-IM-ah-zol], which was approved in 2009. Either drug must be prescribed by a veterinarian after diagnostic tests, and treated cats must be closely monitored.