How Long Does Methimazole Stay In A Cats System?

[Laura304]

We found out our cat has a thyroid problem. We were prescribed methimazole to be taken twice a day. She was on medication for about 2 weeks and then started vomiting a few times a day and also had a red spot below her nose and experienced facial itching. We called our vet and he said to take her off the meds. She has not had any in about a day and a half but she is still vomiting. How long does methimazole stay in a cats system?

 

[Mamanyt1953]

Methimazole leaves the system within about 20 hours. It is a very short-action drug, which is why it is given twice a day. How are the facial itching and the hive beneath her nose? Have they cleared up? She may have irritated her tummy vomiting and that is causing more vomiting. Try withholding food for a few hours, then feeding something gentle on the tummy. I know that either chicken and rice or lamb and rice are considered good for cats with sensitive tummies. If that doesn't work, call your vet!

 

[Laura304]

Thanks for the response! The redness has lessened and she seems to be scratching less. She is still vomiting, not a lot. Just a few times today. Ill see if she continues to vomit and if so, I'll give the vet a call.

 

[Mamanyt1953]

You know, I'm an idiot. It just occurred to me that, although the medication leaves the body very quickly, if she triggered a really strong histamine production, that takes longer to clear the system, and she would have kept producing the histamines until the medication DID clear! She should slowly continue to improve.

 

[carebare]

Yes, for medicine or food reaction, it can take several weeks. For medicines, it can possibly take months. This is what vets and online reasearch told me. Plus my cat had hives that took about 8 weeks to start really clearing up after we stopped the medicine and eating chicken.

 

[Kjl]

my cat had the same reaction the the Methimazole! We had to take him off the pills and get the gel for his ear in a lower dose, which we have not started yet due to him getting a cold. We gave our cat anti nausea pills for a couple days, but it seemed to take him a few days or more to get the meds out of his system and eat normally again

 

[Laura304]

Hello! Just thought I'd post an update incase any one else has been dealing with the same problem. After 2 weeks of being on the thyroid pills, she had a very severe reaction. She had the facial itching, sores/hives, nausea, lethargy, vomiting and loss of appetite. The vet told us to take her off immediately. He gave us anti nausea meds but she was so nauseous, she couldn't even keep them down. We had to take her in for anti nausea injection meds. After being off the thyroid meds, It took over a week and a half to see improvement. She's finally starting to feel better but man, it's been rough! I attached two photos of her skin reaction. It sucks that 85% of cats supposedly do well with this med and my baby was in the small percentage that didn't. I attached 2 pics of her reaction. We will be scheduling the iodine treatment soon! Wish us luck!

 

[Mamanyt1953]

Poor girl! She's been through it, hasn't she?

Got a candle lit for her right now!

 

[Kjl]

So we FINALLY got to try the transdermal gel for my boy's thyroid..and EXACTLY 10 days later, like auth the pills, the vomiting started so now day 2 of that and my poor kitty is again miserable...and of course I gave him the anti nausea meds which he threw up a few minutes later...so we try to wait out the meds leaving his system, but I don't know how much longer we can do this...sooo, I'm off to write a post on "What now?"

 

[Laura304]

Maybe you could call your vet and see if he can get some anti nausea injection meds? That’s what we had to do with our cat when she couldn’t keep the oral nausea meds down. It’s really rough waiting for the thyroid meds to leave their system. It took our cat a week and a half before she even started to feel better. She was absolutely miserable.

We are doing the radioactive iodine treatment on the 19th since she can’t tolerate the meds. I hope your boy feels better soon!

 

[cskormin]

I have been going through this same thing with my 15 year old cat.I had him on Methimazole 5mg twice a day for one month. Toward the end of the month he started throwing up white foam and sometimes his food. He also started scratching his face all up. He was due to go back to the vet to check how the meds were doing with his thyroid levels. Good news, meds worked very well Bad news, he's allergic to it! I took him off the meds. At his age I don't think surgery or idione treatment are practicle. Does anyone know how long a cat can live without treatment? All his other blood work came back great.

 

[Laura304]

I am not sure of lifespan if the thyroid is left untreated. You’d have to discuss that with your vet. I can however tell you that aside from the stress of having to stay in the hospital for a few days, the injection isn’t too bad for the cat. My understanding is that it’s just one single injection and most cats don’t experience any side effects from it. My cat tolerated it just fine. Good luck with your baby!

 

[Laura304]

Also, it’s not usually the most effective treatment but since your cat can’t tolerate the meds, did your vet talk to you about the special diet they can eat? Maybe that could be an option?