Could Methamizole cause lack of appetite 1 month after starting it?

[olliepurrington]

My cat started it July 22nd, 2.5 MG twice daily.

He has a recent history of on/off illness. Previous to the methamizole he didn't want to eat much in late June, early July but seemed to improve.

In between then and now he's been on other meds and had a time where he felt much better.

Starting on Aug 21 he isn't eating again and seems to have an infection with diarrhea and vomiting. At the time he was only taking the methimazole. He's on an antibiotic he started the 22nd.

He's seeing his vet tomorrow to check thyroid levels and follow up on his current issues, and they're aware he isn't eating, but I'm just very worried. He had no food on the 21st, only had 1 teaspoon of tuna and 2 teaspoons of high calorie gel on the 22nd, 1.5 teaspoons of tuna and a 1/4 tube of churu on the 23rd,and nothing so far today. He almost always refuses food.

This is a really complicated situation so the main thing I'm asking here is: is it *possible* that methamizole would cause lack of appetite after one month of taking it? Or would it cause that to happen more quickly? I've heard it can have this effect, and I want to be informed when I take him in tomorrow. Thanks all.

 

[FeebysOwner]

It could be that the dose is too high. It does take a while for the meds to produce results, so I don't think it is out of the realm of possibility that it took a month to cause issues. While 2.5 mg twice a day isn't unheard of, it is always better to err on the side of caution and start with a low dose - many on this site, as well as other sites, seem to think 1.25mg twice a day is a good starting point. The lower dose helps to let a cat's body get used to a new med and subsequent testing (usually 3-4 weeks later) then identifies how to adjust the dose accordingly, along with another follow up testing after another 4 weeks.

There are other cats who just don't respond well to the oral version, so you might have to consider a transdermal version to help with digestive issues.

Of course, you can't rule out other issues coming into play, since he has some and has also been on other medications. Due to the overproduction of hormones from the thyroid, most cats tend to be overly hungry before being treated with methimazole. Your cat could be out of ordinary in that regard, or there very well could be something else affecting him.

 

[olliepurrington]

Thank you Feebysowner. Your insight is very appreciated.

 

[neely]

It could be that the dose is too high. While 2.5 mg twice a day isn't unheard of, it is always better to err on the side of caution and start with a low dose - many on this site, as well as other sites, seem to think 1.25mg twice a day is a good starting point.

I completely agree, spot on!

What was his T-4 when he was diagnosed? Does he have any other underlying conditions, e.g. kidney disease or high blood pressure?
Good luck when you take him to the vet tomorrow, please keep us posted on his progress.

 

[olliepurrington]

Thanks neely, I will!

I can't remember his exact T4 level, but I remember the vet saying it was right on the borderline of high and normal.

As for underlying conditions, we're trying to sort through all his issues and figure it out. It's possible he has IBD or something similar, it's possible he has asthma or something else could be causing breathing trouble. He has repeated upper respiratory problems.

 

[FeebysOwner]

I can't remember his exact T4 level, but I remember the vet saying it was right on the borderline of high and normal.

If that is the case, then 2.5mg twice a day could very well be too high of a dose.

 

[olliepurrington]

If that is the case, then 2.5mg twice a day could very well be too high of a dose.

That makes sense. Would you happen to know if it would be faster getting out of his system than in? Another month of this would be rough.

 

[FeebysOwner]

That makes sense. Would you happen to know if it would be faster getting out of his system than in? Another month of this would be rough.

Good question! But I don't know the answer. I do know that if there are side effects deemed to be associated with too high of a dose (or, a T-4 reading that is too low with the testing), the meds are stopped altogether for at least a week before resuming a lower dose - and, then re-testing in another 3-week period. Not sure that really helps much.

 

[olliepurrington]

That does help. If the vet doesn't suggest stopping for a week, I'll bring it up. Thanks again.

 

[Twylasmom]

That does help. If the vet doesn't suggest stopping for a week, I'll bring it up. Thanks again.

It can definitely cause loss of appetite. Does your cat also seem less energetic? That’s another sign the thyroid level may now be too low. This happened to my cat - started off on too high a dose and even with reducing dose twice she was still hypothyroid. She is currently a week into a 4 week break from the methimazole and is showing improvement in appetite and activity level. That being said, the antibiotic and infection could also be factors for your cat.

 

[olliepurrington]

It can definitely cause loss of appetite. Does your cat also seem less energetic? That’s another sign the thyroid level may now be too low. This happened to my cat - started off on too high a dose and even with reducing dose twice she was still hypothyroid. She is currently a week into a 4 week break from the methimazole and is showing improvement in appetite and activity level. That being said, the antibiotic and infection could also be factors for your cat.

Yes, his energy level seemed to have dropped a lot. I stopped the methimazole for now and he's currently on Mirataz and a steroid and his appetite is slowly improving. Still needs to eat more though but I'm trying to be patient. Glad to hear your kitty is feeling better.