The first line therapy for children with Graves' disease is usually antithyroid drugs -- which include methimazole (brand name Tapazole), and PTU. Radioactive iodine (RAI) and surgery are usually only used as hyperthyroidism treatments if antithyroid drugs fail to control the overactive thyroid.
According to the authors -- Scott Rivkees, MD of Yale University School of Medicine and Donald Mattison, MD of the Eunice Kennedy Shriver National Institute of Child Health and Human Development in Bethesda, MD -- over the past 60 years of PTU and methimazole use, there have been a number of reports of liver failure and death related to use of PTU in children. This problem has not been reported with the use of methimazole in children.
The doctors estimate that from 5 to 10 children die each year from complications of the drug, and are urging colleagues not to prescribe PTU to children as a treatment for an overactive thyroid.
Each year in the United States, 4,000 pediatric patients with Graves' disease are treated with antithyroid drugs, with up to 40% receiving propylthiouracil over the past several years.According to the doctors, more than 1,000 children in the US are estimated to be currently taking PTU in the U.S., and there is no way to manage or prevent the risk of liver damage other than not prescribing the drug to children. To that end, the authors suggest that PTU "should no longer be used as first-line treatment for Graves' disease in children. Alternative treatments should be considered for children who are currently taking propylthiouracil. In this way, it should be possible to end propylthiouracil-induced liver failure in children."
Propylthiouracil-induced liver failure may occur in 1 in 2000 to 1 in 4000 treated children, but the number in whom reversible propylthiouracil-induced liver injury develops may be 10 times that range...
Although more children received methimazole than propylthiouracil during the periods in which propylthiouracil-induced liver failure has been reported, there are no reports of liver failure or liver transplantation in association with methimazole use in children.
Methimazole can also be toxic to the liver, but the damage is significantly less severe, and reversible if the drug is stopped, unlike with PTU.
PTU is also used in adults with Graves' disease, but according to the research, there are fewer liver complications in adults.
If Your Child is Taking Propylthiouracil/PTU
If your child is taking PTU, talk to your doctor about the possibility of switching to methimazole to ensure safer treatment options for your child's hyperthyroidism. But do not take your child off any prescribed medications without your doctor's approval.
Source: Rivkees, MD, Scott and Mattison, MD, Donald. "Correspondence: Ending Propylthiouracil-Induced Liver Failure in Children" New England Journal of Medicine, Volume 360:1574-1575, April 9, 2009, Number 15