Skip header
Free Shipping Over $49
Live Customer Care
Monday-Friday: 8AM - 7PM EST
Saturday: 9AM - 5PM EST
My ProfileMy OrdersMy AutoShipMy RxMy PetsMy VetsMy RewardsSign In
Save Up To 10% On Your First AutoShip

Methimazole Tablet Rx

4.94 out of 5 stars
This Item Ships FREE!
Save 12% on your 1st AutoShip order and 6% on all future AutoShip orders

Please confirm

This item is already on your autoship schedule! Are you sure you want to add it again?

Product Overview

How To Use

What’s in it?



Questions & Answers

Product Description

Methimazole is a medication that is used to treat cats for hyperthyroidism. Veterinarians prefer this drug for treating overactive thyroids. This medication is not a cure, but a treatment.

Sold per tablet.

Who is Methimazole Tablet for?

For use in cats.

Why use Methimazole Tablet?

Features of Methimazole:
  • Works as a preventative for heart failure, heart enlargement, and organ damage
  • Results can be achieved quickly after starting treatment
  • Often used prior to radioactive iodine treatments or thyroid surgeries
  • Protects kidneys for cats who are receiving cisplatin chemotherapy
  • Effectively treats hyperthyroidism symptoms

How does Methimazole Tablet work?

Hyperthyroidism takes place when thyroid hormones are overproduced by the thyroid gland. Methimazole controls or inhibits thyroid hormone production, which reduces hyperthyroidism symptoms.


GenPharm Inc, Par Pharmaceutical, Heritage or other generic brand

Active ingredient(s):

This anti thyroid drug contains 5 mg of Methimazole

How is Methimazole Tablet sold?

Single 5 or 10 mg tablet

What are the side effects of Methimazole Tablet?

Adverse reactions to Methimazole typically occur in the first 3 months of use and are often reduced when a smaller dose is initiated, slowly building to the full dose over the course of those 3 months. If your cat has any of the following reactions or any other unusual signs, speak with your veterinarian:
  • Bleeding
  • Bruising
  • Fever (103ºF or greater)
  • Drowsiness
  • Myasthenia gravis (trouble swallowing and severe muscle weakness), in rare instances
  • Signs of undiagnosed kidney disease
  • Lethargy
  • Vomiting
  • Decreased appetite
  • Liver issues (which may include vomiting, decreased appetite, lethargy, yellowing of the eyes, skin, or gums, dark urine, and facial itching leading to bleeding and/or scratching

What special precautions are there?

Nursing mothers, pregnant women, and women who could become pregnant should always use gloves if they handle Methimazole tablets or the bodily fluids and/or litter of cats treated with this drug.

What to do if overdose?

Immediately contact your closest emergency animal hospital.

How can I store Methimazole Tablet?

Store away from sunlight and heat. Store at room temperature in a dry place. Store in a tight and light resistant container.

Helpful Tips:

Cats with hyperthyroidism, also known as Graves disease, often have high metabolic rates and could show symptoms of thyroid problems, including:
  • Heart murmur
  • Labored breathing
  • Poor coat
  • Rapid heart rate
  • Irregular bowel movement and/or urination frequency
  • Increased thirst and/or appetite
  • Muscle weakness
  • Weight loss

Pharmacists are standing by to offer Pet Parent counseling regarding prescription medication purchased from Allivet before and after dispensing. Pharmacists on duty are available Monday-Friday, 9:30AM - 5:30PM EST and will be on call Saturday 12:00PM - 4:00PM EST for consultation.


Methimazole is not FDA approved for use in veterinary medicine; however, it is commonly accepted for veterinarians to use this medication in cats.
The usual dose in cats is 5mg per cat every 8-12 hours.
Blood tests are repeated every 3-4 weeks until the proper maintenance dose is reached, then blood testing is repeated every 3-6 months.
This medication is needed for life. If the medication is discontinued, the symptoms will reappear.

Main Ingredients

This anti thyroid drug contains 5 mg of Methimazole.
Other ingredients include: Lactose Monohydrate, Povidone, Talc, Croscarmellose Sodium, Magnesium Stearate, Corn Starch.

Know the signs of hyperthyroidism in cats. Click hypothyroidism in cats

Write a Review

Methimazole Tablet

Customer Submitted Questions

the methimazole tablet can I crush it and mix in food

1 Answer
Ask a New Question

Don’t know something or can’t find the information you are looking for? Ask us a question!

*Required Fields
We will ONLY use your email to notify you in regards to your submission.Privacy StatementQuestions & answers are typically posted within 24 hours, pending approval.