From the Guidelines
Tapazole (methimazole) can be alternatively treated with propylthiouracil (PTU), which is the preferred medication in the first trimester of pregnancy and thyroid storm, as stated in the American College of Obstetricians and Gynecologists (ACOG) practice bulletin 1. When considering alternatives to Tapazole, the following options are available:
- Propylthiouracil (PTU): typically dosed at 100-150 mg three times daily initially, then reduced to maintenance doses of 50 mg 2-3 times daily, as it has been found to have similar rates of fetal anomalies and no cases of aplasia cutis compared to methimazole 1.
- Radioactive iodine therapy: offers a permanent solution by destroying thyroid tissue, but often results in hypothyroidism requiring lifelong thyroid hormone replacement.
- Thyroid surgery: provides definitive treatment but carries surgical risks and typically leads to the need for lifelong thyroid hormone replacement. The choice between these alternatives depends on factors including pregnancy status, age, severity of hyperthyroidism, and patient preferences regarding temporary versus permanent treatment approaches. It is essential to monitor patients for potential side effects of thioamides, such as agranulocytosis, hepatitis, vasculitis, and thrombocytopenia, and to adjust treatment accordingly, as recommended in the ACOG practice bulletin 1.
From the FDA Drug Label
Due to the rare occurrence of congenital malformations associated with methimazole use, it may be appropriate to use an alternative anti-thyroid medication in pregnant women requiring treatment for hyperthyroidism particularly in the first trimester of pregnancy during organogenesis. Given the potential maternal adverse effects of propylthiouracil (e.g., hepatotoxicity), it may be preferable to switch from propylthiouracil to methimazole for the second and third trimesters. An alternative to Tapazole (methimazole) is propylthiouracil, especially in the first trimester of pregnancy 2. However, due to the potential maternal adverse effects of propylthiouracil, such as hepatotoxicity, it may be preferable to switch to methimazole for the second and third trimesters 2.
- Key points:
- Propylthiouracil may be used as an alternative in the first trimester
- Methimazole may be preferred in the second and third trimesters due to potential adverse effects of propylthiouracil
From the Research
Tapazole Alternative
Tapazole is another name for methimazole, an antithyroid medication used to treat hyperthyroidism.
- Methimazole is often compared to propylthiouracil (PTU) in terms of safety and efficacy, particularly in pregnant women 3, 4, 5, 6.
- According to a systematic review and meta-analysis, propylthiouracil may be a safer alternative to methimazole for treating hyperthyroidism in pregnant women, with a lower risk of congenital anomalies 3.
- Another study found that PTU-induced liver disease is uncommon but can be catastrophic in pregnancy, while methimazole exposure has been linked to an increased risk of birth defects 4.
- A review of the safety of antithyroid drugs in pregnancy suggested that PTU may be a better option than methimazole during the first trimester, but further studies are needed to determine the best approach 5.
- A study comparing PTU and methimazole in the treatment of Graves' disease during pregnancy found that PTU may be a less desirable first-line treatment due to a possible association with fetal anomalies, but methimazole may be considered a viable second choice in certain cases 6.
- The choice of treatment for hyperthyroidism depends on various factors, including the underlying diagnosis, presence of contraindications, severity of hyperthyroidism, and patient preference 7.
- Other alternatives to methimazole include radioactive iodine ablation of the thyroid gland or surgical thyroidectomy, although these options may have different indications and contraindications 7.