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Felimazole Tablets For Cats

Felimazole 5mg and Felimazole 2.5mg
Felimazole is a drug used in the treatment of an over active thyroid in cats. This disease is also called hyperthyroidism. Felimazole contain the active ingredient methimazole which is also known as thiamazole and is manufactured by Dechra Veterinary Products. It is available as pots of 100 tablets, either pink 2.5mg or orange 5mg tablets. Felimazole is given orally once or twice daily. The exact dosing regime will be determined by your veterinary surgeon.

Felimazole is used in the treatment of hyperthyroidism in cats. This is a condition when the thyroid gland is producing too much thyroid hormone. Felimazole blocks part of the pathway involved in making this thyroid hormone and so reduces the amount of thyroid hormone circulating in the body. Thyroid hormone, also called thyroxine, up regulates the metabolism causing a faster heart rate, an increased appetite and weight loss amongst other signs. Giving Felimazole at a dose that suppresses the hormone will reduce these signs.
Cat Cartoon


- It is only for use in cats suffering with hyperthyroidism
- It is available in two sizes; 2.5mg and 5mg
- The tablets are small and tasteless to make it easier to give them to your cat
- You should only give this if directed to do so by a vet
- The dose will be determined by your vet
- It can be given with food
- It can be given once or twice daily
- If you suspect an overdose, stop treatment and contact your vet as soon as possible.
- If you see side effects associated with this medication then call your vet for advice

Symptoms of Hyperthyroidism
Weight Loss
Increased Appetite
Behavioural Changes
Vomiting / Diarrhoea
Read More


- The most common side effects are vomiting,going off food (anorexia) and pruritus (itching)
- Felimazole should be used with care in cats with existing kidney disease
- Felimazole can also have effects on the liver when given long term
- Felimazole should not be used in pregnant or lactating queens
- Side effects are often mild and temporary and do not require the treatment to be stopped
- In more severe cases, most side effects will resolve after stopping treatment
- Women of childbearing age should wear gloves when handling the litter of cats treated with Felimazole
- Felimazole can have effects on the white blood cells
- Regular blood tests are required for cats taking Felimazole for monitoring
- If you think you see any side effects then contact your vet for advice


- It comes as small, round tablets in two sizes.
- The 2.5mg tablets are pink and the 5mg tablets are orange
- The tablets are given orally with food
- The dose will depend on the level of thyroid hormone in your cat
- The standard starting dose of 2.5mg is twice daily
- This dose is then tailored to suit each patient according to blood tests
- The total daily dose should be divided into two where possible
- The aim should be to give the lowest possible dose that will control the problem
- Do not alter the dose of without speaking to your vet first
- Regular monitoring is essential to check your cat’s progress

Thyroid Gland


- Felimazole tablets are a POM-V (prescription only medicine - veterinarian) therefore they are only available on prescription from your vet
- Cats must be under the care of the prescribing veterinary surgeon and must therefore have been seen sufficiently recently by your vet in order for him/her to prescribe felimazole
- Cat owners may purchase felimazole directly from the prescribing vet or they may request a written prescription that can used to buy felimazole online from a pet dispensary or pharmacy
- Vets cannot refuse to supply a written prescription for felimazole if requested though they are entitled to charge a reasonable fee for doing so
- Since the majority of cats prescribed felimazole are being treated for a lifelong conditions (hyperthyroidism) they will require felimazole for the rest of their life unless the condition is cured with a thyroidectomy or treatment with radioactive iodine.
- You may buy felimazole tablets online quite legally from a supplier such as
- The felimazole we supply is exactly the same as the felimazole you would purchase from your vet though typically 40-60% cheaper


- is run by Pet Prescription Ltd.
- We are staffed by veterinary surgeons, veterinary nurses and SQP's (suitably qualified persons)
- As well as operating many pet information websites we also run
- sells a wide variety of pet healthcare products, prescriptions drugs and pet accessories.
- As practicing veterinary and animal professionals we have a wealth of experience and are extremely well placed to answer your pet related queries
- As pet owners ourselves we understand the importance of pets to their owners
- Owning a pet can be expensive - We want to help you care for your pets with expert advice and discounted pet medicines and accessories

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The contents of this website are the personal opinions of the author and should be used as a guide only. No liability is accepted for accuracy of content or any other matter. If your pet is unwell we strongly recommend you seek the advice of a qualified veterinary surgeon. Articles are written and/or edited by S J Bagnall BVetMed MRCVS
This website has been created by for information purposes only. Petprescription is a retailer of Felimazole, but is not affiliated with or related to the manufacturer of Felimazole in any way. The contents of this website are not sponsored or endorsed by the manufacturer of Felimazole.
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