Written by Dr. Feargus McConnell, BVSc on the Jan.16, 2024
Petdirect is dedicated to providing educational pet health content for pet parents. This article was written and reviewed by veterinary professionals to answer common questions about your pet’s medication. Our focus is on delivering unbiased information to help you understand how medication works, its potential side effects, and FAQs for your reference. Always administer medication directly as prescribed by your vet. This article shouldn’t take the place of advice from your vet.
Felimazole contains Methimazole as the active ingredient which is commonly used to treat hyperthyroidism in cats. Hyperthyroidism in cats is usually the result of a benign change in one or both of the thyroid glands. This results in an overproduction of thyroid hormone and affects the cat’s metabolism. Felimazole can be used to stabilise hyperthyroid cats prior to surgery to remove the thyroid. Common signs of hyperthyroidism can include weight loss despite increased appetite, increased vocalisation, increased drinking and urination, vomiting. The coat of affected cats may appear unkempt or greasy. Cats with hyperthyroidism can appear hyperactive, irritable and at times aggressive.
The active ingredient, Methimazole works by inhibiting the use of iodine by the thyroid gland, essentially decreasing the thyroid gland’s ability to produce thyroid hormones. It's important to note that methimazole is not a cure but helps manage the symptoms by controlling hormone production.
Always follow the advice provided by your veterinarian. Felimazole tablets should typically be started at a low dose and then adjusted after three weeks based on the cat's individual response. Preferably, the daily dose will be split in half and given morning and evening. However, if the cat is difficult to give tablets to, then the tablet can be given once daily. Cats should always have access to water while being treated with this medication.
Missed dose:
In case you miss a dose, administer it as soon as you remember. However, if it's almost time for the next dose, it is advised to wait until the next dose is due. Do not give two doses at the same time.
Overdose:
In case of accidental ingestion or overdose, contact your veterinarian or the New Zealand National Poisons Centre at www.poisons.co.nz/animal-helpline/ or 0800 869 738.
Methimazole should be used cautiously in pets with liver disease, autoimmune diseases, kidney disease, or blood abnormalities. Treatment may reveal pre existing underlying kidney disease. It is vital to contact your veterinarian immediately if you notice these side effects.
Side effects most common within the first three months may include a lack of appetite, vomiting, diarrhoea, and depression, lethargy.
Felimazole should be stored at controlled room temperatures below 25°C, avoiding extreme heat. Ensure the container is tightly sealed to protect from moisture and light. Keep out of reach of children and pets.
Pregnant women should wear gloves when handling this medication. Wash hands thoroughly after handling this medication. As thiamazole is a suspected teratogen, women of childbearing age should wear gloves when handling cat litter used by treated cats.
Prior and during treatment, it's recommended to monitor the cat's health through appropriate blood tests. Regular monitoring every few months is crucial, and for cats on higher doses, more frequent checks may be necessary. Adjustments to the medication should be made as advised by your vet based on these health checks. Note that it is necessary that your cat revisits your veterinary surgeon for assessment and monitoring tests. These are recommended at 3,6,10 and 20 weeks after starting treatment and thereafter every 3 months.
How long does Felimazole take to work on cats?
How long will my cat be on Felimazole?
Can Felimazole interact with other medications?
Can Felimazole be used for cats and dogs?
Felimazole is a common medication for managing Hyperthyroidism in cats. Consistent application and veterinary monitoring are crucial for its effectiveness. We hope this article provides a clear understanding of Felimazole for your pet. Remember, always seek advice from your veterinarian for any health-related decisions for your pets.