# Thyroxine vs Soloxine?



## cprcheetah (Apr 26, 2009)

Shellie is on Thyroxine (which is generic soloxine) twice a day. Her levels are normal. Are you giving it with a meal? They have better absorption if it is given 1 hour before or 3 hours after a meal....something I learned when Shellie had her last panel done by Dr. Jean Dodd's. She has had much better results with the Thyroxine now.


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## Katie and Paddy's Mum (Mar 31, 2010)

Hmm, that is a really great question. I would be inclined to say leave him with the thyroxin, but I definitely think you need the advice of a trusted vet. Do you trust this new vet?

Also, my understanding is that a T4 reading itself does not tell you very much. The most accurate reading for their true levels would involve a Free T4 and a TSH test. My vet explained it to me like this. A T4 reading only shows you how much gas you have in the tank. The Free T4 shows you how well the engine (body of the dog) is metabolizing that gas (thyroxine). I thought it was a great analogy and really helped me to better understand the difference between the two tests.

In most vet offices, they can run a T4 in-house, as they can a standard CBC test. The Free T4 is done by dialysis, that is why it has to be sent out.

I know I am not answering your original question. But I am definitely curious to know what others say!

Glad to see, however, that Brooks levels seem to be finally getting into normal ranges!!

Kim


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## lgnutah (Feb 26, 2007)

I have taken Brooks to two different vets, each time asking for the complete thyroid panel. Both vets said "not necessary". The first one (who sent the test out for analysis, but just the free T4) said we would maybe consider the more complete test if we can't get his thyroid T4 down. The second one said she had the equipment in her office and it didn't need to be sent out.
So I would need to try to find yet a third vet if I want the complete thyroid panel done?


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## IowaGold (Nov 3, 2009)

If he's already on the meds, the full panel won't tell you nearly as much as having the full panel done BEFORE starting meds. Personally, I usually recommend new clients that have had hypothyroidism "diagnosed" based solely on a T4 stop their thyroid meds for 6-8 weeks then retest with the full panel. I've found several dogs that really weren't hypothyroid at all.


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## Megora (Jun 7, 2010)

IowaGold said:


> If he's already on the meds, the full panel won't tell you nearly as much as having the full panel done BEFORE starting meds. Personally, I usually recommend new clients that have had hypothyroidism "diagnosed" based solely on a T4 stop their thyroid meds for 6-8 weeks then retest with the full panel. I've found several dogs that really weren't hypothyroid at all.


This makes me feel so much better.... :uhoh:

I was thinking about just doing the T4 test ($54) vs the full panel ($114). The tech told me that for new patients they do the full panel because it gives them the whole picture. The T4 is only for patients who have already been diagnosed with thyroid problems, and that's the test they do twice a year or whatever. 

I went with that, but I was wondering in the back of my head whether it was necessary. Whether they did the T4 test or the full panel, they'd be sent to MSU. 

^ I don't think Jacks has thyroid problems, but I thought it was worth checking...


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## IowaGold (Nov 3, 2009)

Yep, once (properly) diagnosed, a simple T4 or free T4 is great for monitoring. Just not so great for diagnosing! You can use it as a screening tool to see if you need the big panel, but I'd rather spend the extra $50 and know FOR SURE rather than potentially having to come back and have more blood drawn (and then spend the extra money).


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## Dallas Gold (Dec 22, 2007)

I just picked up a copy of Toby's latest thryoid test we did on Tuesday. The test our vet uses to monitor his absorption of thyroid pill is called a T4 Post Pill thyroid, which is different from a straight T4 or Free T4, I think....  The lab's normal values are 3-5. This one came in at 3.3, down from a similar test in January that came in at 4.1. Tomorrow I plan to graph out all his test results (same test) for the past year but it definitely appears he's seasonally hypothyroid. He is high normal in the colder months and he is low in the warmer months. His vet tells me she sees this more often with some of her feline patients but it is certainly plausible for dogs as well. So we'll be beginning the adjustment in meds for the warmer seasons now. We're using a generic thyroxine. 

I was confused in reading all the posts on GRF showing T4s at much lower ranges than we were getting and now I realize our vet uses a completely different test. So, what is the standard practice for testing absorption of thyroid meds? This test is done after a 12 hour fast and we dose him with the supplement between 4 and 6 hours before drawing blood. This is also different from what others here do fasting and timing wise.


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## lgnutah (Feb 26, 2007)

I am confused too, because I read when someone is having blood drawn to send off to Dr Dodds, there is a requirement that the dog not have eaten for some period of time. For my dog's most recent test I was told to feed him as usual that day, and to give his morning dose of thyroxine (levothyroxin) at 8 in the morning, but to NOT give the 2nd dose, and to bring him to her office at 6 pm. I gave him a very light feeding at 2 pm and his blood was drawn around 6:30 pm (so 10 1/2 hrs after his last thyroxin dose, and 4 1/2 hrs after eating).
This test had him at a mid-normal reading (2.4), the first time he had been normal since testing began 6 months previously.


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