What is this medication for?
Methimazole belongs to the class of medications called antithyroid medications. It is used to treat hyperthyroidism (overactive thyroid gland). It prevents the thyroid gland from overproducing thyroid hormone, but does not interfere with the actions of thyroid hormone.
It may take weeks to months before methimazole has its full effect on the symptoms of overactive thyroid (e.g., palpitations, sweating). During this time period, other medications may be used to control these symptoms.
Your doctor may have suggested this medication for conditions other than those listed here. As well, some forms of this medication may not be used for all of the conditions discussed here. If you are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.
What form(s) does this medication come in?
Tapazole® is available as:
Some medications may have other generic brands available. Always ask your doctor or pharmacist about the safety of switching between brands of the same medication.
How should I use this medication?
Methimazole is usually given in 3 equal doses daily at approximately 8-hour intervals. This medication can be taken with or without food.
Adults: The recommended starting total dose of methimazole is 15 mg to 60 mg daily divided into 3 doses taken at 8-hour intervals. Depending on the response, your doctor may decrease the total dose to 5 mg to 15 mg daily.
Children: For children, the dose is determined by the child's body weight. The usual starting dose is 0.4 mg per kg of body weight divided into 3 doses and given at 8-hour intervals. Depending on the response, your doctor may decrease the total dose to 0.2 mg/kg of body weight daily.
Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.
It is important that this medication be taken exactly as prescribed by your doctor. The 3 daily doses should be taken as close to every 8 hours as possible so that blood levels are kept as constant as possible. If you miss a dose of this medication, take it as soon as possible and continue with your regular dosing schedule. If it is almost time for your next dose, take both doses together. If you miss more than one dose, contact your doctor or pharmacist for advice.
Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.
Who should NOT take this medication?
Do not take methimazole if you are allergic to methimazole or any ingredients of the medication.