Felimazole side effects ? - Getting really worried now :(

[CarolM (Wendolene)]

No problem.  I hope it helps and Fluffers is soon back to her usual happy self 

[J (Indoorcatsuk)]

Thank you so very much for your time and trouble Carol, it is totally appreciated.
Btw, I'm not bothered at all about ' dealing ' with medical personnel and there ( sometime ) attitude. My human daughter has some medical conditions that mean I deal with a lot of doctors and I've questioned ( and stopped them ) on occasion.

My husband was all for halving the dose anyhow, so hopefully I'll get him well-armed too by reading your very helpful advice.

[CarolM (Wendolene)]

I've been trying to find the reference to the American vet association recommendations for you but I keep coming up against members only sites.  I'll keep trying though because I know from experience what vets can be like when you question their treatment, however politely you put it.  They will tell you that anything below 5 mg bd is a sub-therapeutic dose which may well be the case (although some people on a board I was on had cats well-controlled on less).  However, the point is that slow upward titration to a therapeutic dose is better for the cat.
I have found a couple of references though.  One is in the book 'Consultations in feline internal medicine' by John R August, published by Elsevier Health Sciences.  It says 'the starting dose is now **2.5mg twice daily** then recheck in 3 weeks. If any adverse symptoms are noted, then recheck sooner. It only takes **1 week** for Tapazole to stabilize in the bloodstream. Past recommendations were as high as 5mg 3 times a day for 3 weeks.   The other is mentioned on Tanya's feline crf site under related diseases (www.felinecrf.org).
Your  Fluffers sounds even smaller than my Tiny (2.8 kg) and he had terrible side effects including constant vomiting when he was started on 5 mg bd.  At one stage he was so poorly I thought I was going to lose him (and I think the vet did too) so I stopped all medication (with grudging vet approval).  He got better (well, still hyper-T of course) and we then started treatment again on a lower dose. It was always a bit of a balancing act between controlling the thyroid and making him vomit but we got there in the end.
If you and your vet do decide to go down the lower dosage route you may need to change Fluffers to carbimazole (which is what used to be used until recently) rather than Felimazole because the tablets are not coated and can therefore be split.

By the way, during my searching I found arthralgia listed as a common side effect of felimazole so that may be Fluffers problem and it may resolve when she gets used to her new euthyroid state.

[J (Indoorcatsuk)]

That's what concerns me Carol, given according to the internet the size of the cat has no effect on the dose and given my Fluffers is TINY and I mean TINY, she is even smaller than a six month old kitten, she is extremely petite, I can't help but think this is like hitting her with a medical sledgehammer. Yes, she is on 5mg twice daily.
I am prepared for CRF possibility, those she is happy enough. Obviously she needs this medical treatment, but I think I need to have words with the vet about the American recommendations. I picked her up earlier and she didn't feel as if she has gained any weight really.
The thing is they had great difficulty even getting an injection into her at the vets ( had originally taken her for cystitis treatment and general check ), the vet actually had to take her out of the room to get help with that ( and so not to distress my hubbie ! ). She had an audible heart murmur.
One other thing I noticed was the other day she fell asleep on me and I could smell her on me quite strongly afterwards. However, the vet said her gums were good.
I just want her to enjoy her life.

[CarolM (Wendolene)]

I think its a good idea to get her (name?) checked at the vets.  Felimazole can have some very nasty effects on the blood and although these effects are extremely rare it would be as well to rule them out.  It would also be useful to know whether anything is going on with her kidneys - forewarned is forearmed.  That said, she may just be adjusting to her new non-hyper state.  I think vets here in the UK introduce the felimazole too quickly (usually start at one 5 mg tablet twice daily) and the sudden drop in thyroid levels comes as a bit of a shock to the system.  The closest thing I can compare it with is a heroin addict suddenly stopping the drug.  Their body has become dependant on it even though its not good for them and the sudden withdrawal causes all sorts of physical problems that can make them very poorly.  In the US vets have wised up to this situation and the recommendations of the American Veterinary Association are now to introduce the felimazole more slowly. 

[J (Indoorcatsuk)]

This morning I'm even more worried, tho she purrs as soon as I stroke her, her mobility seems noticeably different to before she started taking the tablets, a definite struggle to sit down etc, ( not like she's in pain but in an ' old bones ' sort of way ) and a showing of unsteadiness when getting up to walk.
Oh ****.
Am going to get my husband to take her to the vets I think. I'm very worried about CRF, tho the vet said he wasn't worried about the size of her kidneys particularly, think I might get one of the other vets at the practice to have a look this time.

[Gill (sneakiefeline)]

Pavs cat Boy is on this and I know he is being sick and Pav posted today that the vet thinks its the tabs.

[J (Indoorcatsuk)]

I don't know about the wobbliness but I wouldn't worry overly about her being quieter - thats probably a sign that the tablets are working.

Of course, it's so obvious but I never thought, thanks so much for posting.

[CarolM (Wendolene)]

I don't know about the wobbliness but I wouldn't worry overly about her being quieter - thats probably a sign that the tablets are working.  Hyperthyroid makes a cat more active and often more vocal so once its under control its not unusual to see a calmer cat. One thing to be aware of is if she does have any kidney issues then they may appear to worsen as the thyroid gets controlled.  This is because the increased blood flow that you get in a hyperthyroid cat can actually mask poor kidney function and once it normalises the true extent of the problem reveals itself

[Garfield&Gypsy]

Jet (Angel) suffered from Hyper-t. on the tablets she was more normal.
Before them she spent all day scrounging for food and not dealing with grooming etc. after a few weeks she was washing again (obviously an improvement to her coat) and she was eating more normal and slowly put on weight.
She did however have a few instances of facial trauma where she had a few scabs which se kept irritating, but no vomiting or hairloss.

[J (Indoorcatsuk)]

I know there's a lot of fellow hyperthyroid cat mums here. Has anyone noticed any side effects ?
Tah internet comes up with these:
    * Vomiting
    * Hair loss
    * Skin rashes
    * Reduced white blood cells
    * Self trauma of the face
    * Liver damage
    * Spontaneous bleeding
    * Jaundice
    * Agranulocytosis¹

My gal is 17, TINY ( always has been ).
I don't know if it's just me being more sensitive and hyperaware of her every move and so on, but her coat seems different since she has been taking the tablets ( only a couple of weeks ) and she seems quieter, and a bit ' wobbly '. Now I've lost 3 of my old dears in the past 4 years so I know what can happen etc, but I dunno, the vet wasn't particularly worried about her re:CRF, he said her kidneys didn't seem worrying. She just seems a bit ' older ' than before taking the tablets.
She's actually vomiting less than she did before the tablets, her appetite has increased, but no increase in water consumption or anything particularly worrying. I'm probably fretting over nothing. She is due back at the vets in a couple of weeks.