Antithyroid Drugs are a class of mediations, Thioamide class, that blocks the binding of iodine.
This class is regarded as a hormone antagonist and it directly affects thyroid hormones.
Essentially this group of medications affects overactive thyroid.
Antithyroid drugs decrease the levels of the two hormones produced by the thyroid:
1.) Thyroxine (T4)
2.) Triiodothyronine (T3)
- Propylthiouracil (PTU)
- Carbimazole – [found in the United Kingdom]
- Agranulocytosis [a decrease of white blood cells] – seen more often with PTU but can also be seen in methimazole
- Aplastic anemia
- Sore throat
Use During Pregnancy:
- Propylthiouracil (PTU) used to be the drug of choice during pregnancy
- This was because it was believed to cause less severe birth defects than methimazole.
- Current recommendations for propylthiouracil is that it be used during the first trimester only.
- Rare liver damage has been seen in some people.
- After the first trimester, women should switch to methimazole for the rest of the pregnancy.