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Side FX of Tapazol/Methimazole

Posted: Sun Jul 28, 2019 3:55 pm
by MickeyOnTheCoast
Hey all. My 13 y/o male cat was diagnosed with Hyperthyroidism about 3 weeks ago - side note he is also FIV+ since birth. The vet recommended Hills Y/D food (wet and dry) as well as 5mg Tapazol (Methimazole) 1/2 pill 2x/day (2.5 mg morning 2.5 mg night). The first 2 weeks he seemed to be doing better (gained weight, happier overall). However I noticed yesterday he has been excessively grooming, scratching in particular his chin, face, ears, and feet. He also seems to be acting strange, meowing a lot, sleeping in weird spots around the house and his pupils look dilated. Heading to the Vet tomorrow, just wanted to see if anyone had any insight or similar problems with their cat. Thanks in advance!

Re: Side FX of Tapazol/Methimazole

Posted: Tue Jul 30, 2019 2:27 pm
by Kay
side effects of HT medications seem to be mostly gastric, and your boy's problems seem to indicate some kind of allergy, which would indicate the food is the source

I thought the Hills Y/D is recommended only when cats can't tolerate HT meds, or are impossible to pill - I've not heard of a vet recommending both - and as he is only 13 years I would have thought a restriced diet. possibly for 4 or 5 years, is a real problem, as indeed is medicating for several years

has your vet discussed radioactive iodine treatment, or surgery, as alternatives? Having had a cat with HT some years ago, I discovered many UK vets are not that well up on the disease, compared with US ones, and you may well find more info on the internet than from your vet

Re: Side FX of Tapazol/Methimazole

Posted: Thu Sep 26, 2019 5:27 am
by Mollycat
Bit late I know and I'm sure the vet has already advised but ...

Yowling especially late night can be a HT symptom as can pupil changes and facial itching. Also restlessness which would include sleeping in strange places. Cats can also have voice changes (mine has and it's still odd post treatment) and their eyes can go a bit copper-coloured. Y/d should work quickly if given strictly as an only food, no treats, nothing else. Hills advised me (when I queried this) that even rainwater in coastal areas can contain enough iodine to mess up what y/d is supposed to achieve.

Sounds like either your cat is sourcing food elsewhere or maybe the HT is quite bad, if the vet says both diet and meds and he hasn't improved much. I don't know how FIV interacts with HT.