The hardest part of dealing with hypothyroidism in your dog is getting the proper diagnosis. Hypothyroidism is both over- and under-diagnosed at the same time.
Diagnosing hypothyroidism is not straight-forward.
If not tested correctly, there is a high likelihood of misdiagnosis.
The main reason why your dog might get wrongly diagnosed with poor thyroid function is when your vet tests for T4 while your dog is sick or on certain medications. Many diseases and medications cause low thyroid hormone levels in the blood while thyroid function might be perfectly fine. For example, when Cookie had pancreatitis, her thyroid hormone tanked. The only reason it appeared on that blood panel in the first place was that it was some kind of “lab special deal” at the time.
The good news is that once diagnosed, treatment is relatively simple.
There are, however, a few things to keep in mind if you want your dog’s thyroid replacement therapy to work satisfactorily. These things are important and yet they seem to be widely unknown, including veterinarians.
Thyroid replacement therapy dosage
There are two things that might be a bone of contention when it comes to thyroxine (thyroid hormone replacement) dosing.
First, correct dosage is calculated based on ideal weight. Not your dog’s current weight, but what should be their ideal weight. It is quite likely that weight issues had been one of the reasons you tested thyroid function in the first place.
Cookie wasn’t obese but definitely heavier than I wanted. In fact, this was one of the main reasons I insisted on testing – managing Cookie’s weight was a nightmare in spite of her being very active and eating less and less. Short of starving her, I couldn’t have fed her less. Yet, she wouldn’t drop a pound.
In Cookie’s case, the vet an I had some disagreements as to what Cookie’s ideal weight should be. As a rule of thumb, it’s a good idea to go by how much your dog weighed at two years of age (if that information is available and if your dog wasn’t already overweight at that time.)
How often should be thyroid meds given?
When Jasmine was diagnosed with hypothyroidism, she was put on what was the correct dose for her weight. Her prescription was to be given once a day. However, in dogs, the estimated half-life is somewhere between 10 to 14 hours. Do you see a problem there?
That’s why the correct way is to medicate your dog every 12 hours to keep the levels reasonably stable. I didn’t know that back then and the vet, clearly, wasn’t aware of that either.
Thyroid meds should not be given with food.
Unless you work with Dr. Dodds’ Hemopet, chances are you, or your vet, don’t know this either. Giving your dog thyroid replacement with their food reduces its bioavailability, meaning that your dog will end up under-dosed. That is because calcium interferes with its absorption.
The proper way is to give it an hour before, or three hours after a meal. Since the most common way of medicating dogs is hiding the meds in their food or treats, that can be a problem even if you don’t give it with a meal. If that’s what you need to do, Dr. Dodds recommends giving it with peanut butter because an only a trace amount of calcium is present.
This has been working well for Cookie, though we did run into consistency issues with some of the quality peanut butter out there. Eventually, we found a brand that stiffens up just right with refrigeration so it can be used to hide the pills in it. Coincidentally, it is a chunky type, which, I believe, helps with concealing the pill even better. Since it’s full of chunks, the pill just feels like another one. I suspect that in smooth peanut butter the pill would stick out like a sore thumb to Cookie.
We’ll be testing Cookie’s response to therapy in a couple of weeks.
She has been losing weight, though, feeling and looking good so it seems that her dose is correct.
Overview of Thyroid Gland and Testing Protocols