Recent Veterinary News

Latest posts from Dr. Marie's blog...

Dr. Marie recommends:

A new treatment for hyperthyroid cats

If you find this information useful, please spread the word by sharing this on Facebook with your friends or Tweeting this article.

Do you have a cat with hyperthyroidism? Until now, we have had two treatments we could use for these cats:

  • Methimazole (also known as tapazole or felimazole): This is a medication that is given either once or twice daily in tablet form. It works very well. Some vets will use a cream form that is absorbed through the ear. This is easier to give than pills, but this doesn't always work well.
  • Radio-iodine therapy: This works well, but is very expensive. The cat's thyroid gland is treated with radioactive iodine. Most of these cats do not need medication after receiving this treatment.

But now there is a new treatment that is causing quite an excitement amongst veterinarians. Hill's has produced a food called y/d which they believe is an excellent treatment for hyperthyroidism. (Disclaimer - I have no affiliation with Hill's).

Hill's y/d

Is y/d medicated?

My first thought was that they had made a food medicated with methimazole. I was wondering how this was going to work though as there would be issues with cats potentially getting too much medication. But I was wrong!

There is no medication in the food! Instead, the food is iodine reduced. The reason that this works is that the thyroid gland needs iodine in order to make thyroid hormone. So, if very little iodine is supplied, then the cat can't over produce thyroid hormone.

How y/d works:

(Click image to enlarge)

how does yd work in treating hyperthyroidism?

Does y/d work as well as medication?

According to Hill's, every hyperthyroid cat that they put on y/d returned to normal thyroid levels. Most were improving within 3 weeks. Some took a few weeks longer to return to normal. If these studies are valid (which they likely are) then feeding y/d may be just as good as giving medication.

Can a cat become hypothyroid (low thyroid levels) on y/d?


Can a hyperthyroid cat eat other food when they're on y/d?

No. If your cat eats other food or treats then they will be getting a normal level of iodine and then the enlarged thyroid gland will be able to overproduce thyroid hormone again.

Is it safe for a non-hyperthyroid cat to eat y/d?

So far in Hill's studies of up to 2 years, they have not found any negative consequences of feeding an iodine reduced diet to normal cats. In fact, some people believe that all cats should be fed a reduced iodine diet. It's possible that the recommendation for iodine levels in cat food is actually too high.

When is y/d available?

Hill's y/d will become available in the fall of 2011. It is only available through your veterinarian.

My thoughts on y/d

I'm really excited about this new food! But I'm also cautiously optimistic. While the studies that Hill's have done are impressive, they're not extremely large. I'll feel much more comfortable prescribing y/d when the food has been out for a while and we see if there are any side effects.

With that being said, I'm still going to offer this choice to my clients with newly diagnosed hyperthyroid cats. I'll discuss all of their options and let them know that with pills or radio-iodine therapy I'm really comfortable with advising owners how to treat. While I recognize that feeding a special food is way more convenient than giving medication, I need to advise my clients that if they choose the food they're venturing into "experimental" territory.

I'll keep you posted!

Once I have some experience with using this food for cats with hyperthyroidism I'll let you know!

Dr. Marie.

Search Ask A Vet Question:

Leave a comment below!

(Dr. Marie does not answer questions via the comments section, though!)

Dr. Marie was quick to respond and thorough in suggesting treatment for my cat. I am so thankful- I have been so worried about my cat. Now I have additional options to discuss with my vet.

The service was incredibly fast and the vet's suggestions were right on target. This was incredibly helpful given that none of the vets in my area, mine now included, will take off hours calls now.

Dr. MarieDr. Marie is a veterinarian who practices in a busy animal hospital in Ottawa, Ontario. She created Ask A Vet Question as a resource for good, accurate veterinary advice online. Dr. Marie treats dogs, cats, hamsters, guinea pigs, and rats. She has been a vet since 1999.

Is an online vet visit just as good as a trip to your veterinarian? No! But, many times, asking an online veterinarian a question can help save you money. While Dr. Marie can't officially diagnose your pet or prescribe medications, she can often advise you on whether a vet visit is necessary. You can also ask Dr. Marie for a second opinion on your pet's condition.