methimazole dosage

Hello,
Mt 14 year old baby has hyperthyroid. My vet started her on 5mg twice a day. I was wondering if this is a large dose or normal. At first he said 3 times a day then changed to twice a day. Also how long before the meds start working? She was calm last night but I heard her sneeze several times. I hope she's not getting an upper respitory infection. Guess I'm just a worier. Thanks!

Originally Posted by Cathyy

Hello,
Mt 14 year old baby has hyperthyroid. My vet started her on 5mg twice a day. I was wondering if this is a large dose or normal. At first he said 3 times a day then changed to twice a day. Also how long before the meds start working? She was calm last night but I heard her sneeze several times. I hope she's not getting an upper respitory infection. Guess I'm just a worier. Thanks!

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That is a higher dose than any of my cats who've had hyper-T and been treated with methiamozle (or Tapazole).

Here is a link with a bit of info on this: tanya's site - hyper t tx's

I'll ask our TCS vet tech to comment,

Thanks, I appreciate any info I can get. I'm from a small town and we don't have the best vets here. Their test only show up to 7. He said hers was higher than that but he had no way of knowing how much higher.

Originally Posted by Cathyy

Thanks, I appreciate any info I can get. I'm from a small town and we don't have the best vets here. Their test only show up to 7. He said hers was higher than that but he had no way of knowing how much higher.

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I sent a pm to Dr Doolittle (vet tech but this great call name) and asked her to comment.
I do remember that my Christopher <RB> was over 12 on his T4, and his dose was 2.5 mg twice a day...but I do not know if other parameters factored in to your vet's decision on this doseage, and I'm no vet

Thanks! I was wondering why he started her out on so strong of a dose. I may cut back and wait to see what the vet tech that you know says. Thanks for asking him. Cathy

Hi, just to let you know that my cat Sophie had hyperthyroidism and was started off neomercazole (spelling correct?) 3 times a day to start with. I believe this is the same medication that is called methimazole in the US. Sophie was monitored very carefully, both heart rate, weight and blood tests and was reduced after a couple of months to 2 pills per day. She then got lethargic and put on loads of weight, still being monitored, the bloods showed that she had gone the other way and was hypothryoid. Her pills were cut again down to 1 pill per day, when she improved.

It takes a few months to get the dosage right, but Sophie was much better when it was sorted out. She eventually died suddenly of something unrelated to her hyperthyroid condition (acute pancreatitis). Best of luck with getting your kitty sorted out and it may take a while.

Hi Jan, Thanks for writing. Do you remember what dosage the medicine was started out with? Also trying to find out how long it takes for it to calm them down. Friskey is stictly an inside cat and wakes us up several times a night. The vet says it may take a week or two but I'm hoping it won't be take that long. We're worn out. Thanks! Cathy

It was definitely 3 tablets per day when she started. The vet told me that it was guidelines from the drug manufacturer, 3 pills a day to start off with. Can't remember how long it took to work, Sophie never had over activity problems!!! Far from it! Her idea of exercise was raising and lowering her eyelids. She was diagnosed because I had an "elderly cat profile" blood test done at her annual vaccination/check up. I remember she had gone thin before diagnosis though, despite eating voraciously.

I don't want to worry you, but have you had her kidneys checked as well? 14 year old Jimmy was diagnosed hyperthyroid at the same time as Sophie. The same blood test showed him to have "mild" kidney disease. He went on to pills for this and for the hyperthyroid, but the over active thyroid had been masking signs of kidney disease. When the thyroid gland was sorted out, his kidneys deteriorated dramatically and he died only about 6 months later. In fact tomorrow, 18th December, is the first anniversary of his death. (Still love you Jimmy). The vet said that it often happens, hyperthyroidism masks kidney disease, which becomes more apparent after thyroid treatment. Sophie's kidneys were fine, she was retested 12 months later and they were still going great guns!

Just to add - there's a support group for people with hyperthyroid/hypothyroid cats here http://groups.yahoo.com/group/feline-hyperT/

My vet supposedly checked for kidney disease. I'll ask to see the test results again to make sure. She was quiet and calm went I went home for lunch. I'm hoping she's feeling better. The vet said hyperthyroidism for cats is similar to what a person on speed all the time would feel like. Sorry to hear about Jimmy. It'll be hard when Friskey's time comes. I hate to even think about it. I also have a 10 year old shepherd with congestive heart failure. Have her on Lasix. All my babies are seniors. I'll check out the support group website you sent. Thanks again!

The tapazole dose your vet chooses is usually based on her clinical signs and T4 level. If her blood tests have shown that her T4 is very high he may have wanted to put her on a higher dose of tapazole initially to get her symptoms and hormone levels under control. Usually additional bloodwork is needed to asses how the meds are working. When her T4 drops, the vet may decide to lower the dose.
Hyperthyroidism is caused by a tumor of the thyroid gland causing it to produce too much hormone. The disease can vary from cat to cat as can the amount of medication needed to control the disease. I would do as your vet has suggested and not adjust the dose on your own. If you have concerns, talk to your vet about them. If you are not happy with what he has to say then perhaps you could find a vet you are happier with. Not all vets are created equally!

Thanks Dr. Doolittle, I feel much better having you comment

Anytime! Sorry it took so long, I have had a bad flu for the last few days. Feels like someone is kicking my head into a wall right now

oh yuck...hope you feel better soon. DH brought home "something" and unfortunately, I've caught it. I told him to hurry up and feel better so now he can take care of me!

Originally Posted by Cathyy

Hello,
Mt 14 year old baby has hyperthyroid. My vet started her on 5mg twice a day. I was wondering if this is a large dose or normal. At first he said 3 times a day then changed to twice a day. Also how long before the meds start working? She was calm last night but I heard her sneeze several times. I hope she's not getting an upper respitory infection. Guess I'm just a worier. Thanks!

Click to expand...

When I first got Spot and found out he has hyperthyroidism, we put him on 5 mg twice per day as well. After a few weeks, he was retested, and his thyroid was low. We adjusted the dose to one and a half pills total (I usually give him one pill at night and half a pill in the morning) per day, and now he's in the normal range. It takes a few weeks and a few tests to find the right dose, and every cat is different.

I hope her sneezing gets better! Spot started having sneezing fits last week, but they seem to be subsiding some now.