Methimazole

Why has my veterinarian prescribed this medicine?

Methimazole is used to lower the amount of thyroid hormone in the blood. This medication will not cure hyperthyroidism, but will help control the disease. 

How do I give this medication?

For oral formulations:

• This medication may be given as a tablet or compounded oral liquid.
• If the medicine is a liquid, measure the dose with reasonable care.

For transdermal formulations:

• Wear gloves.
• Measure the dose with reasonable care onto an applicator or gloved finger.
• Ensure that you do not get the medication on your skin, if you do, wash your hands as soon as possible.
• Apply the medication to the pinna or other skin surface recommended by your veterinarian, and gently rub the medication into the skin.
• Before applying the next dose, clean the application site with a cotton swab moistened with warm water.
• Try to give this medication at about the same time each day.
• DO NOT give your pet more medicine than directed and DO NOT give the drug more often than directed.
• DO NOT stop giving this medication to your pet unless directed by your veterinarian. Call your veterinarian ahead of time if your pet needs a refill.
• Try not to miss giving any doses.

What if I miss giving a dose?

Give the dose as soon as possible. If it is almost time for the next dose, skip the missed dose, and continue with the regular schedule. Do not give the pet two doses at once.

How do I store this medicine?

• Keep this medicine out of reach of children.
• Store this medicine in a cool, dry place at room temperature.
• Do not store this medicine in the bathroom, near the kitchen sink or in damp places. The medicine may break down if exposed to heat or moisture.

What are the potential side effects?

• The following side effects may occur, but usually decrease over time: loss of appetite, vomiting and drowsiness. Some cats develop an itchy face.
• Notify your veterinarian if symptoms are troublesome and continue.
• Other side effects may occur. If the pet experiences anything unusual, contact your veterinarian. Very rarely, bone marrow suppression can occur. If you notice any unusual bruising or lethargy contact your veterinarian as soon as possible.

Are there any possible drug interactions?

• Make sure to tell your veterinarian what other medication you are giving to your pet.
• Quite often, your veterinarian may prescribe two different medications, and sometimes a drug interaction may be anticipated. In this case, your veterinarian may adjust the dose and/or monitor your pet more closely.
• Anticoagulants can potentially interact with methimazole.
• Contact your veterinarian if your pet experiences any unusual reactions when different medications are given together.