​​​Managing Thyroid Disease in Cats

Be sure to watch the video at the bottom of this article for additional information on giving the medication.

Have you recently noticed that your cat has one, some, or all of these symptoms?

  • Raggedy coat 
  • Ravenous appetite and eating tons of food but losing weight
  • Hungry all the time but then won't eat
  • Rapid weight loss; their collar is suddenly hanging off them
  • Agitation
  • Racing heart, high blood pressure
  • Vomiting brown bile

It may be Thyroid! It is a common ailment especially for older cats. My Alex cat turned 13 this year, and he recently had to go on Methimazole (the drug of choice for hyperthryoid). Fortunately it's easy to administer and inexpensive!

Thyroid disease causes an overproduction of thyroid hormones, T3, and T4. Cats actually have TWO (2) glands (I was surprised to learn this). They are on either side of the throat, and the Veterinarian will palpate the gland on exam (mine even had me palpate it which was a weird feeling!). The Vet will also do blood work. Initially your cat will start on a low dose, which will be adjusted every 10 days for the first 10-30 days. Another blood panel will be required to determine if the optimal dose has been reached. After that, it's very important to have a physical including blood workup every 6 to 12 months to ensure that is still the correct dose, and monitor any potential impact to the kidneys.

Per Texas A&M College of Veterinary Medicine:
"An enlarged thyroid gland may be palpated, but a normal exam does not rule out the possibility of hyperthyroidism. To confirm the disease, the animal's thyroid hormone level will be checked through blood work."

If left untreated - or if the medicine dosage is not regularly monitored via blood work every 3  months - secondary problems can arise such as heart enlargement, an elevated heart rate and liver enlargement, eventually leading to death. In the meantime, both the cat - and you - are miserable. Not a good path to take.

A low cost medication called Methimazole is the standard way to treat the disease. It decreases  the amount of the hormones released from the thyroid glands.  

Its essential that when your cat first goes on Methimazole, a 30 day follow up blood test occurs to determine:

  • if this is the right dose, and
  • if its negatively impacted the cat's liver, kidneys, blood pressure and/or heart rate.

The medication must be given once or twice daily for the rest of the cat's life. It is essential they get the full dose or they will continue to be ill.

To avoid the cat pill spitting (my Alex, my Duchess, and my Jewel were champion pill spitters, one holding it in her mouth until I left the room then spitting what was left under the couch. It took me weeks to figure out this was why she was not getting well because I insisted to the Veterinarian she was taking it and not spitting it). You also must avoid the cat not eating the whole portion of food in which you hid it - or some other pet eating it. If they hate pill pockets (every cat and dog I've ever had), you can ask your vet to have it reformulated in to a liquid or compounded into a gel that is rubbed into the ear and absorbed that way. The video below shows how to administer the gel.

As you can see in this video below of me administering the medication to Duchess, that is what I have done with all of my Thyroid cats. Its easy, takes seconds, they think its a massage and don't fight it, and ensures they get the entire dose so you're not wasting your time nor money and still having an ill cat!

Per Texas A&M College of Veterinary Medicine (and my Veterinarians):

"Radioactive-iodine therapy is becoming increasingly popular when dealing with hyperthyroidism in cats. For this long-term treatment, the cat is injected with the radioactive iodine, which destroys the tissue of the overactive thyroid gland.  Although this procedure is usually very effective, it is more expensive and requires the cat being confined to the hospital while the radioactivity decreases."

In reality, a blood panel, a comprehensive exam, and sometimes also an ultrasound (as was the case with my cat), must be done to determine if you cat is eligible for such a treatment. Your Veterinarian has to write up the case, and send it to one of only a few clinics that do this - which may or may not be anywhere near where you live. Your cat may or may not qualify. Mine did not.

If this happens, or there is not a clinic in the area in which you live, or you can't afford it, medication is a one option. In severe cases where medication cannot control the disease, surgical removal is an option (this is what happened with my Duchess). The surgeon in my cat's case, only had to remove 1 of the 2 glands. Since she still had 1 gland making T3-T4 (at normal levels) she did not have to go on supplements post surgery. This is very common.

You and your veterinarian will determine which treatment option is best for your cat.