Propylthiouracil (PTU), an anti-thyroid drug, associated with risk of serious liver injury
6/04/2009 Posted by D.K. Mangusan Jr., PTRP
Reports to FDA’s Adverse Event Reporting System (AERS) suggest there is an increased risk of hepatotoxicity with PTU when compared to methimazole (MMI). FDA has identified 32 AERS cases (22 adult and 10 pediatric) of serious liver injury associated with PTU use. Of the adult cases, 12 deaths and 5 liver transplants occurred. Among the pediatric patients, 1 case resulted in death and 6 in liver transplants.
In contrast, for MMI 5 AERS cases of serious liver injury were identified. All five cases were in adult patients and 3 resulted in death.
Both PTU and MMI are indicated for the treatment of hyperthyroidism due to Graves’ disease. However, healthcare professionals should carefully consider which drug to initiate in a patient recently diagnosed with Graves’ disease. In addition, physicians should closely monitor patients on PTU therapy for symptoms and signs of liver injury, especially during the first six months after initiation of therapy.
PTU is considered second-line drug therapy, except in certain patients who are allergic to, or intolerant of, methimazole. Because a rare birth defect has been reported with methimazole and not with PTU, PTU may be more appropriate for patients with Graves’ disease who are in the first trimester of pregnancy.
Sources:
U.S. Food and Drug Administration (June, 2009). Propylthiouracil (PTU)-Induced Liver Failure. Available at http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/DrugSafetyInformationforHeathcareProfessionals/ucm162701.htm
U.S. Food and Drug Administration (June, 2009). FDA Warns About Serious Liver Injury Associated With Anti-Thyroid Drug. Available at http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm164207.htm
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