Is an overactive thyroid gland treatable in cats?

Older cats are prone to hyperthyroidism or an overactive thyroid and it is one of main reasons why cats lose weight.

The metabolic rate of a cat as well as all other mammals is controlled by the thyroid glands in the neck. If the gland does not work in the way it should and it becomes overactive, it means that it continues to produce thyroxine and so the metabolic rate becomes higher to the point where it is uncontrollable.

The symptoms

Weight loss is the main symptom along with an increased appetite. This is due to the fact that they are burning their food at such a rate that they need to continuously eat. They can become thirsty and may even vomit or have diarrhoea along with an increased heart rate and breathing. Due to increased energy levels they can become hyperactive but they can also become excessively aggressive.


A check of the heart rate will usually point to a potential thyroid problem if it is over 180-200 beats per minute. However, a small blood test will check for thyroxine levels. If these are high, then it will mean that the cat has hyperthyroidism.



Fortunately, it is possible to treat the problem quite easily and there are four options available.

Medication such as Felimazole and Vidalta can be used to help reduce the amount of thyroxine that is produced and that is given in tablet form. A blood test is carried out regularly to ensure that the correct dosage of medication is being given but the tablets will have to be taken for the rest of the cat’s life.

A special diet can help to combat the problem as the thyroid glands need iodine in order to create thyroxine. A special diet will be prescribed that is iodine free although this is not as effective as medication although it is easy to give to the cat. The cat is not allowed any other foods or treats as this will cause the diet to be ineffective.

Surgery is also an option and this will involve completely removing the thyroid gland. However, cats with the condition do not cope well with anaesthetics and so medication has to be used to stabilise the condition before surgery is carried out. An operation will completely cure the condition although the other thyroid gland can be affected so occasionally both glands have to be removed.

A course of radiation therapy may be used in order to destroy the thyroid tissue. The cat will have to remain in isolation before they return home but if the treatment works then the condition will be cured. This is a costly treatment but one that works well.

If the condition is not treated, what will happen?

If your cat does not receive the right treatment then it will either starve to death or die of heart failure. This is down to blood clots causing the heart to work harder until it eventually stops. Therefore, it is advised that treatment is sought as quickly as possible.

cat with vet

Author Bio

Medicines4Pets are an online retailer of prescription pet medicines, pet supplies and accessories.

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8 thoughts on “Is an overactive thyroid gland treatable in cats?

  1. Pingback: Is an overactive thyroid gland treatable in cats? – Jeanne Foguth's Blog

  2. Pingback: Is an overactive thyroid gland treatable in cats? — Katzenworld | My Health Selections

  3. Susiewoo says:

    I currently have my third cat with hyperthyroidism and he’s a nightmare to medicate. I’ve also had one with hypothyroidism and, although an underactive thyroid is much less common in cats than overactive, it can be something else to watch out for. On the whole, vets are much better clued up on thyroid than doctors 😉

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