What is the use of Tapazole (Methimazole)?

From the Guidelines

Tapazole, or methimazole, is the preferred treatment for hyperthyroidism in pregnancy, with the goal of maintaining FT4 or FTI in the high-normal range using the lowest possible dosage. When treating hyperthyroidism, especially in pregnant women, it's crucial to consider the safety and efficacy of the medication. According to the American College of Obstetricians and Gynecologists (ACOG) practice bulletin on thyroid disease in pregnancy 1, methimazole is one of the thioamides used to treat hyperthyroidism in pregnant women, with no significant differences found between methimazole and propylthiouracil in terms of mean FT4 or TSH levels in newborn cord-blood samples.

Some key points to consider when using Tapazole include:

• The medication should be taken at the same time each day, with or without food
• Regular blood tests are necessary to monitor thyroid function and blood counts during treatment
• Common side effects include skin rash, itching, nausea, headache, and joint pain
• More serious but rare side effects include agranulocytosis, which requires immediate medical attention if symptoms like fever or sore throat develop
• Women treated with methimazole can breastfeed safely, as stated in the ACOG practice bulletin 1

It's essential to monitor patients closely for side effects and adjust the dosage as needed to minimize the risk of adverse effects while effectively managing hyperthyroidism. The dosage of Tapazole typically ranges from 5 to 30 mg daily, depending on the severity of hyperthyroidism, and is often divided into three equal doses during initial treatment 1.

From the FDA Drug Label

Methimazole tablets, USP are indicated: In patients with Graves’ disease with hyperthyroidism or toxic multinodular goiter for whom surgery or radioactive iodine therapy is not an appropriate treatment option. To ameliorate symptoms of hyperthyroidism in preparation for thyroidectomy or radioactive iodine therapy. Methimazole inhibits the synthesis of thyroid hormones and thus is effective in the treatment of hyperthyroidism. Tapazole is another name for methimazole, which is used to treat hyperthyroidism.

• The drug is indicated for patients with Graves’ disease or toxic multinodular goiter.
• It works by inhibiting the synthesis of thyroid hormones. 2 2

From the Research

Tapazole Overview

• Tapazole, also known as methimazole, is a medication used to treat hyperthyroidism.
• It works by reducing the production of thyroid hormones in the thyroid gland.

Side Effects of Tapazole

• Agranulocytosis, a rare but serious side effect, has been reported in patients taking tapazole 3, 4, 5, 6, 7.
• Severe hepatotoxicity has also been reported in some cases, often in conjunction with agranulocytosis 3, 6.
• Other symptoms of agranulocytosis include fever, sore throat, and infection 7.

Management of Agranulocytosis

• Discontinuation of tapazole is necessary in cases of agranulocytosis 3, 4, 5, 6, 7.
• Alternative treatments, such as propylthiouracil, beta-blockade, saturated solution of potassium iodide, cholestyramine, steroids, lithium, and plasmapheresis, may be used to manage hyperthyroidism and control symptoms of thyrotoxicosis 4.
• Patients with severe agranulocytosis may require a longer time to recover and may incur high hospitalization costs 7.

Risk Factors and Prevention

• The risk of agranulocytosis is higher in patients taking tapazole, especially during the first few months of treatment 5, 7.
• Patient education and monitoring of blood cell counts and liver function are important to prevent and detect agranulocytosis early 7.