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Felimazole for Cats

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Felimazole Tabs 2.5 mg, 100 Tablets
Price: $17.71
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Felimazole Tabs 2.5 mg, 30 Tablets
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Item #: 1041403 -
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Felimazole Tabs 2.5 mg, 100 Tablets
Price: $10.63
Item #: 1041404 -
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Felimazole Tabs 5 mg, 100 Tablets
Price: $29.59
Item #: 1017071 -
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Felimazole Tabs 5 mg, 100 Tablets
Price: $9.04
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Felimazole Tabs 5 mg, 100 Tablets
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Item #: 1041406 -
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Products 1-6 of 6

Feline Hyperthyroidism Treatment Medication

Felimazole pet medications effectively manage the symptoms of hyperthyroidism in cats and helps prevent heart failure and other complications from developing. Felimazole tablets are not approved by the FDA for use in cats, but many veterinarians commonly prescribe Felimazole to treat hyperthyroidism in cats. This medication is not a cure for hyperthyroidism and must be taken throughout life to control symptoms. Available in quantities of 100 tablets in 2.5 mg and 5 mg strengths.

Comparable Trade Names & Generics

Felimazole is the first licensed medical treatment for hyperthyroidism in cats. Hyperthyroidism occurs when the thyroid gland produces too much T3 and T4, two hormones that affect nearly all the body's organs. Without treatment, hyperthyroidism can lead to enlargement and thickening of the heart's left ventricle. This complication can progress to heart failure and death. Felimazole can manage the symptoms of hyperthyroidism in cats and help prevent complications. Felimazole is not a cure for a hyperthyroidism.

Benefits of Felimazole:

  • Small sugar-coated tablets make administration easy
  • Lower incidence of side effects than propylthiouracil
  • Controls symptoms of feline hyperthyroidism, including increased thirst and urination, weight loss, increased appetite, vomiting, hyperactivity, and diarrhea
  • Works rapidly to manage hyperthyroidism and associated symptoms
  • Protects against heart failure caused by untreated hyperthyroidism
  • Available in two strengths for easy dosing
  • Available in two strengths: 2.5 mg and 5 mg
  • Improves quality and length of life for thyroid-disordered cats

The usual starting dose of Felimazole is 2.5 mg every 12 hours, with the maximum single dose being 10 mg and the maximum total daily dose being 20 mg.

This medication may also be used prior to radioactive iodine treatment or thyroid surgery.


  1. Put on gloves before handling this medication.
  2. Administer Felimazole to your cat whole. Do not crush or break the tablets.
  3. Give this medication with or without food.
  4. Wash hands thoroughly after handling Felimazole to prevent absorption of the medication through the skin.

Frequency of Use:

After 3 and 6 weeks of treatment, testing to check hormone levels should be performed and the dose of Felimazole should be titrated to reflect test results.


Store at room temperature in a tightly closed container. Keep away from moisture. Keep out of the reach of pets and children.

It is a violation of Federal Law to use this product in a manner inconsistent with its labeling.

The active ingredient in Felimazole, methimazole, is a thioureylene antithyroid drug that works by inhibiting thyroid hormone synthesis.

Felimazole is available only by prescription.

Felimazole (methimazole)

Active ingredient: Methimazole

Inactive ingredients: Lactose Monohydrate, Povidone, Talc, Croscarmellose Sodium, Magnesium Stearate, Corn Starch


Keep this product out of reach of children and animals. Do not use or store in or near open flame or heat.

Felimazole is not for use in cats with a known hypersensitivity to methimazole, carbimazole, or polyethylene glycol.

Felimazole is intended for use in cats only. This medication is not for humans or other animals.

CAUTION: This medication is contraindicated for use in cats with renal failure, autoimmune disease, or primary liver disease. Do not use Felimazole in cats with blood disorders or in pregnant or lactating queens. This medication may induce bleeding diathesis.

Wash hands with soap and clean water after handling this medication, coming into contact with the litter of treated cats, or exposure to the urine, feces, or vomit of treated cats.

Adverse effects of Felimazole include headache, vomiting, abnormal vocalization, skin lesions, fever, itching, arthralgia, and pancytopenia. If body aches, bruising and bleeding, blood in the stool or urine, a peeling or blistering skin rash, dizziness, drowsiness, headache, nerve pain, join pain, hair loss, jaundice, loss of appetite, or swelling occur, call your veterinarian for a prompt appointment.

Symptoms of overdose may include vomiting, nausea, joint pain, headache, itching, swelling, easy bruising, fever, and excessive bleeding. Seek emergency veterinary attention if symptoms of overdose are suspected. Also, seek emergency care for potential allergic reactions. Symptoms of an allergic reaction to Felimazole include trouble breathing, swelling of the face or mouth, rash, hives, or itching.

Cats taking Felimazole should not undergo vaccination.

Do not give this medication to cats taking digoxin, beta-blockers, propranolol, warfarin, theophylline, or metoprolol without veterinary approval.

Warranty and Manufacturer Information:

NADA 141-292, Approved by FDA

Distributed by: Dechra Veterinary Products, 7015 College Boulevard, Suite 525, Overland Park, KS 66211

For a copy of the Material Safety Data Sheet (MSDS) or to report adverse reactions call Dechra Veterinary Products at (866) 933-2472.

FELIMAZOLE is a trademark of Dechra Ltd

© 2008, Dechra Ltd


NAC No.: 12920140