Endocrine System Home > Precautions and Warnings With Methimazole
Before beginning treatment, it's important to be aware of safety issues with methimazole. For example, the antithyroid medicine can cause severe liver damage, low white blood cell counts, and low blood platelets. In addition, alcohol should be avoided while taking it. Other warnings and precautions for methimazole apply to women who are pregnant or breastfeeding.
What Should I Tell My Healthcare Provider?Prior to taking methimazole (Tapazole®), you should talk with your healthcare provider if you have:
- Liver disease, such as hepatitis, cirrhosis, or liver failure
- A bleeding disorder
- Any allergies, including to food, dyes, or preservatives.
- Pregnant or thinking of becoming pregnant
Specific Methimazole Precautions and WarningsSome warnings and precautions to be aware of prior to taking methimazole include the following:
- Methimazole can cause low blood cells, such as low white blood cells and low blood platelets. These conditions may be quite serious. Your healthcare provider should monitor your blood counts to check for such problems -- usually using a simple blood test. Let your healthcare provider know if you develop any signs of such problems, such as:
- Sore throat
- Easy bruising or bleeding.
- Methimazole can cause serious liver reactions, which may result in death. Let your healthcare provider know right away if you develop signs of liver problems, such as:
- Yellow eyes or skin (jaundice)
- Upper-right abdominal pain (stomach pain)
- Loss of appetite
- Elevated liver enzymes (found using a blood test).
- You should avoid alcohol while taking this medicine, as additive effects, such as increased drowsiness, confusion, or memory loss, could occur.
- Methimazole can potentially interact with other medications (see Drug Interactions With Methimazole).
- Methimazole is a pregnancy Category D medication, which means it presents clear risks during pregnancy. Check with your healthcare provider before taking this drug when pregnant (see Methimazole and Pregnancy).