Felimazole Medications for Cats

Hyperthyroidism is especially common in elderly cats.
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If your sweet kitty has the glandular condition hyperthyroidism, his veterinarian may prescribe Felimazole, an oral antithyroid medication known generically as methimazole. This drug manages and treats the various unpleasant symptoms of hyperthyroidism, from weight loss to unusual appetite boosts.


Felimazole helps to manage feline hyperthyroidism by obstructing the thyroid gland's making of the thyroid hormone. Although the coated tablet medication does not cure the disorder, it keeps symptoms under control -- and your cat living a happy, healthy and relaxed life for as long as possible.

Hyperthyroidism Symptoms

Feline hyperthyroidism affects mostly senior cats. When a vet opts for Felimazole as a treatment option, the goal is to minimize the discomfort associated with common hyperthyroidism symptoms, including higher appetite, weight loss, feelings of weakness and uncharacteristic hostile behavior. Other symptoms include restlessness, hyperactivity, labored breathing, depressive mood, frequent urination and throwing up, as well as rapid heart rate, messy-looking fur, diarrhea, panting and excessive shedding.

Side Effects

Before you consider Felimazole as a management plan for your fluff ball's hyperthyroidism, discuss with your veterinarian the possible side effects of the drug. Some common side effects that are associated with Felimazole use include throwing up, exhaustion, itchy face, darker-colored urine, appetite changes, yellow gums, excessive meowing or yowling, and the emergence of skin lesions. Upon observing any of these symptoms, take your feline friend to the veterinarian immediately -- just to be on the safe side.


Felimazole is not necessarily safe or suitable for all cats with hyperthyroidism. Some contraindications are associated with the medication. Felimazole is not intended for use in felines with medical conditions such as kidney failure, liver disease, autoimmune disease or anemia. It also is not suitable for female cats that are either pregnant or nursing kittens. Discuss with your veterinarian your cat's medical history or any present health conditions in the event that any contraindications may exist. Make your vet aware of other medications that your cat may be taking, as well.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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