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Please note: All Prescription drugs require a prescription from the prescriber prior to shipment.

Methimazole rx


What is Methimazole?

Hyperthyroidism is a common disorder of the endocrine system found mostly in middle aged to older cats. It occurs when there is an excess amount of thyroid hormones produced thus causing an increase in metabolic rate. Methimazole in a drug that is given for life to help control your pet’s hyperthyroidism. Methimazole requires a prescription from your veterinarian, and is sold per tablet.




  • Effectively treats hyperthyroidism in cats
  • Quick results
  • Less side effects


Do not use in pregnant or nursing animals. Do not give your pet a live vaccine while giving methimazole. Contact your veterinarian immediately if your pet develops signs of an infection.Tell your veterinarian if your pet has an allergy to methimazole or if your pet has liver disease, a blood disorder, or a weak immune system. Inform your veterinarian of any other medications, including vitamins and supplements your pet may be taking while receiving methimazole.

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What happens 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 your pet two doses at once.

Possible side effects of Methimazole:

Stop giving methimazole and contact your veterinarian if your pet develops any of these serious side effects; fever, chills, body aches; easy bruising or bleeding, unusual weakness; blood in the urine or stools; severe blistering, peeling, and skin rash; nausea, low fever, loss of appetite, dark urine, jaundice. Continue giving methimazole and talk to your veterinarian if your pet experiences headache, drowsiness, dizziness; mild nausea, or vomiting; itching; muscle, joint, or nerve pain; swelling; hair loss.


Store methimazole at room temperature, away from moisture and heat.


Give this medication as directed by your veterinarian. Do not give in larger amounts, or give it for longer than recommended by your veterinarian. Methimazole can be given with or without food. Keep plenty of water available for the pet to drink.


All weightsThe usual initial dose varies from 2.5-5mg 2 or 3 times a day. Periodic blood testing is required to monitor liver function and for any toxic effects on blood cells


Do not use!


Do not use!


Active Ingredients (per tablet)Amount
Methimazole5 mg

Other Ingredients: Lactose Monohydrate, Povidone, Talc, Croscarmellose Sodium, Magnesium Stearate, Corn Starch.
  • Effectively treats hyperthyroidism in cats
  • Quick results
  • Less side effects


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