Propylthiouracil (PTU) Alert
Jun
3
Written by:
6/3/2009
Thanks to Mardi for letting me know about this alert that the FDA issued today:
[Posted 06/03/2009] FDA notified healthcare professionals of the risk of serious liver injury, including liver failure and death, with the use of propylthiouracil (PTU) in adult and pediatric patients. 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. Although both PTU and MMI are indicated for the treatment of hyperthyroidism due to Graves’ disease, healthcare professionals should carefully consider which drug to initiate in a patient recently diagnosed with Graves’ disease. 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 should not be used in pediatric patients unless the patient is allergic to or intolerant of MMI, and there are no other treatment options available.
My comments: PTU has been available for more than 50 years and previous studies have shown that adverse effects were associated with inappropriately high doses of PTU. I frequently hear from patients who are being prescribed doses as high as 450 mg when studies show starting doses of 200-300 mg are more appropriate.
The lowest dose of PTU needed to keep FT4 within range regardless of TSH is a good guideline. Too often, doctors prescribe high doses in an effort to raise TSH. It's important for patients to keep copies of their lab reports and make sure their ATD dose is appropriate.