I am sorry you have lost your cat. Felimazole can cause various reactions, some fatal, but the time between starting the tablets and the death of your cat is quite rapid for the onset of these adverse reactions, although not entirely impossible. Although their is a temporal link between administering the tablets and the symptoms your cat developed this does not necessarily mean they were definitely the cause and there may have been something else that your vet failed to diagnose, but not having examined your cat that is difficult for me to say. At the least I can say that what you describe is not normal at all despite what your vet said and based upon your description I am very surprised your vet did not get you to bring the cat in straight away when it became ill. As far as the kidney issue goes, your are correct, but I would be surprised if kidney failure from the reduction in thyroid hormone was the cause of death, unless the bloods showed that there was very significant kidney failure before the Felimazole was started. Unfortunately without a post mortem I suspect you will get no satisfactory explanation as to the cause of death. If you are unhappy I would suggest you speak to your vet initially and see what they have to say, before taking things any further.

My 17 year old male cat has just been diagnosed with hyperthyroidism after taking him to the vet on Friday suffering from very labored breathing, lethargy and listlessness despite having a very rapid heart rate. These outward signs were very sudden but, as my vet explained, cats are very apt at masking illnesses until they are pretty advanced. Anyway, my cat was prescribed Felimazole, 1x2.5 a day which was started that evening. My concern is that since visiting the vet (2 days now) which was incredibly stressful for the cat in the condition he was in, his breathing has seemed to worsen slightly and any slight movement causes him to lie back down and shallow breathe. He is unstable on his hind legs and can only manage a couple of feet without lying down and concentrating on breathing. I have taken to hand feeding him whilst he is sitting as this seems the less stressful way he can eat. In short, he appears much more poorly now than he did before taking him to the vet. Part of me is wondering whether this is something to do with the ordeal of being taken to the vet and another part is wondering whether this is a temporary side effect of Felimazole, even though it is only day 3 of administering the medication. Blood tests and a urinalysis showed that his kidney and liver functions were perfectly normal, but that he was suffering from severe dehydration and also cardiomyopathy due to the hyperthyroidism and it is his difficulty in breathing and rapid heartbeat that concerns me the most. Does this rectify itself once on Felimazole or is the heart damage irreversible? It is very painful for me to see my animal's labored breathing and inability to move at ease but perhaps I am being inpatient and need to allow the medication to take it's course before panicking.

The most important thing here is that your cat has heart failure and Felimazole will not change that in all likelihood (it might if your cat was asymptomatic of its heart disease but the laboured breathing suggests otherwise). The heart disease needs to be addressed or your cat will continue to deteriorate rapidly. Your cat probably has a pleural effusion (fluid around the lungs squashing them) if the breathing is laboured and this needs to be drained and then medication administered for heart failure.

Was the thyroid hormone level elevated - you say the liver and kidneys were normal but the cat was severely dehydrated - first I am surprised that the liver enzymes are normal in a hyperthyroid cat, particularly one in heart failure, second I wonder what in the blood results firstly indicated dehydration and secondly cardiomyopathy; the latter cannot be diagnosed on a blood test but some tests are indicators of heart disease.

Overall it seems to me that maybe your vet might not be quite on top of this case. I would take your concerns back to the vet and if you are not happy then ask to see a cardiac specialist.

My cat started taking a 2.5mg dose of felimazole tablets twice daily 5 days ago but has not shown any signs of improvement yet, if anything i think he has deteriorated further, he has now totally lost his appetite, continues to lose weight, seems to be losing his balance, do you think he is having an adverse reaction to the tablets and should i stop administering them? I will of course be taking him back to my vets for their opinion but i don't want to keep giving him the tablets if they are making him worse! i'm not sure how old he is but i have had him for 10 years andd he was a rescue cat aged at least 2 years but could have been older.
If he is having an adverse reaction to the tablets what other medication could he take? the vet told me he was very high at 119 and normally he should have been between 19 and 64.

It normally takes 10-14 days to see a response. If your cat has stopped eating I would stop the tablets and see if the appetite returns. If it does then restart the tablets at one tablet a day. There are other drugs - carbimazole (Vidalta) is better in my opinion and safer.

My 14 year old British shorthaired cat (neutered female) has had hyperthyroidism for more than 2 years, but she still has periodic spells of refusing food. We gently syringe feed her small supplements of convalescent cat gloop for a few days to add to her picky eating and usually, she picks up and starts eating again. She is thin, but maintains her weight fairly well as a rule.

Her dosage of Felimazole is high - 7.5mg daily in two doses. She accepts the tablets without demur and isn't bothered by the plastic pill popper gadget. Her blood levels are checked about twice or three time a year, but they vary. We watch her respiratory and heart rates if we're concerned and check that her ears are cool. She has some renal problems, so she has special food and she also has Metacam for arthritis in a leg which she broke in a fall as a kitten.

Recently, we had to be away for 3 weeks on a work assignment and she didn't do well in her usual cattery, lost almost a kilo in weight and seemed to be 'out of balance' with her medications. Today, we're worried because she won't settle and keeps shouting. When we cuddle her, she purrs, but won't settle even with attention and reassurance and she resumes shouting the minute we return to work. This is unusual because she's normally a relaxed cat who snoozes contentedly while we work. She doesn't seem to be in pain and there's no visible problems, but she has warm ears and seems to be quite hyper in general. We can't count her heart beats because she fidgets so much.

We know she can't go on for ever, but generally, the quality of her life has looked pretty good up to now.

Are such periodic crises likely to be part of the pattern of her illness, or should we be more worried?


Could this be some kind of crisis?

Hyperthyroidism is generally easy to manage and most patients are looking good pretty quickly and the hyperthyroidism then generally causes no problems. From what you describe the renal problems are much more likely to be causing the variation, possibly in conjunction with the metacam (stomach irritation). Addressing these may help - appropriate diet, drugs to protect the stomach.

Hi,

Our cat, we think, is about 16-17 years old. She developed hyperthyroidism about two years ago. We were prescribed one 2.5mg tablet per day. Her weight and health has deteriorated since then, but our vet insists that this is the maximum dose for our age of cat, but i am not sure that I agree. However, I do not want to overdose our cat. Can anyone make any suggestions.

Thanks, Neil

The dose is dependent on the blood thyroid hormone level - whatever dose is necessary to keep it normal. It would be wise to make sure that the problem is not something else such as kidney disease before altering the dose, particularly since the dose has not needed to be altered for so long.


Sorry for the delay in replying but I have been on holiday.

our elderly cat has been on felimaazole twice a day for approx 4 months now. had blood test done after first couple of months and she seemed to have responded well. has put weight on, and is eating well, but this last month her character has changed - she barely moves from a spot in the kitchen - only getting up to eat, and this afternoon i found her lying in the litter tray - which i have never seen her do before. she appears to be 'spaced out'. should i reduce dosage to just one tablet a day - planning on visiting vets again. thanks

Lethargy could reflect overdosage but may be due to other problems, especially kidney failure which can be unmasked once cats are treated for hyperthyroidism. It would be wise to check the thyroid hormone level and kidney function before altering the dose.

My cat Eddie must be about fifteen now and last year he became very thin although eating like a horse exuse the pun so I took him to the vet who did a blood test for suspected underactive thyroid and the tests came back positive and now he takes two 2.5mg twice a day one in the morning and one in the evening.
He has always been a very independent cat and not a lap cat but a very gentle sort so when I give him his tablets I just talk to him and tickle his
chin and then tip his head back and make sure that the tablet goes down the middle of his throat. I am very good at remembering to administer them but one particular day I almost forgot and the only reason I remembered was that I looked down and Eddie was at my side enough to say you need to give me my tablet mum and as strange as it seems it was almost time for his evening dose.
I have a good vet and I do take him once every six months for a check up.
For those that are worried about giving their cat this drug just look up the eventual condition that underactive thyroid leaves a cat when
untreated!! I will do my best to give him a little longer in his lovely surroundings.

Best Wishes to all my cat lovers X

HI J Ellis,

I'm glad your cat Eddie is doing so well on the medication, but just wanted to clarify for other readers of this post if it's an under-active or over-active thyroid problem. From your description it sounds very much like hyper-thyroidism i.e. an overactive thyroid which causes the weight loss and voracious appetite you describe. If so, the medication is indeed a great way to manage this condition if your cat is able to tolerate the tablets, which in your case it sounds like he is - even to the point of reminding you!

Best of luck for his continued well being & thanks for sharing your experience.

Zara The Vet

My question about hyperthyroidism and Felimazole is how long does it typically take to get the medication balanced? My cat Sebastian was diagnosed with hyperthyroidism two months ago, in June 2012. He is getting Felimazole 2.5 mg twice a day. He responded immediately, within 48 hours he was no longer crying, wandering endlessly, or licking the fur off his legs. He gained weight immediately. In the past two weeks he seems to have plateaued - he is slightly restless and has had a few moments of over-grooming, and this week he is very picky about eating, so his weight has dropped slightly.

Is this a normal fluctuation in the process of stabilizing the thyroid? Do cats typically go up and down a bit during the early months of medication? Should we try a higher dose of medication? Should he have another thyroid test? He just had one 3 weeks ago and it looked good. While my vet is very good, he tends to overprovide a bit, so I like to be well informed when I talk to him so I know what questions to ask, and how to consider his advice.

Thank you.

Walter Beswick Wrote:
-------------------------------------------------------
> Hi,
>
> Felimazole tablets may be enteric-coated ( I am
> not sure), which protects the contents from being
> destroyed by the acids in the stomach, and allows
> them to go on to the intestine where the coating
> is dissolved and the active ingredient absorbed.
> If so, your vet is absoutely right.I do not think
> I said the ONLY reason for not crushing them was
> possible risk to you, but that is part of the
> reason for giving them whole.
> Giving tablets to cats can be very traumatic for
> the cat and for its owner, and I can suggest no
> easy way.
> W

Hi I give my cat his tablet in a small cube of cheese, he loves it, hope this idea helps someone too, JJ

We took our 15 year old cat for her yearly vaccination and as she needed an anaesthetic for dental work and had lost weight whilst eating well the vet suggested blood tests. Her T4 came out as 71 nmol/L (normal 19-65), her Alk Phos 112 (normal 7-75), ALT 126 (normal 30-60). Everything else was normal except a slightly rasied urea of 9.2 (normal 3.5-8.0) which the vet said might be down to dehydration due to fasting for the blood test and the hot weather as her creatinine was a very normal 95 (normal 40-180). We were told she was slightly hyperthyroid and should start on 2.5mg of felimazole twice daily. I am wondering if she is being overdosed as her hyperthyroidism was only slight and we should perhaps cut it down?
She has deteriorated since starting the felimazole from being a normal active cat to being listless and refusing her food. She is losing and consuming a lot of fur and seems to be damp around the mouth, she is constantly grooming and often had fur stuck to her mouth as well as developing lots of fur clumps (she's long haired). The vet says this is a symptom of hyperthyroidism but she didn't have it before starting the medication. I saw her drinking water for the first time ever this week (but it been very hot). But I am most worried that she isn't eating much.
To complicate matters further I accidentily cut into her neck on Sunday whilst cutting off a big clump of fur so she had to go back to the vets for emergency stictches and they did the dental work at the same time. She is currently on antibiotics and painkillers too for her teeth (antirobe 25mg 2 tabs daily and loxicom) but I don't think these are the cause of her symptoms as this is her second course of antirobe and she was OK on the first one and she has been on loxicom for a few weeks now with no symptoms until she started felimazole. Thanks for reading, hope you can help.

Hi!

A quick question - can Felimazole cause vomiting? My 16 year old cat has recently been prescribed Felimazole and has now been taking 2 tablets a day for just over 2 weeks. Her blood tests have all come back normal apart from the thyroid (surprising the vet, for a cat of her age), but in the last couple of days, she has started being sick two or three times a day, so all her food is coming back up again. As she had just starting to put on weight again, this is worrying. Yesterday she was also really lethargic and 'just not right' (I'm sure all pet owners will know what I mean by this)... she was just lying in the middle of the hallway and not wanting to move. Are these side effects of the medication and will it pass as her body gets used to a) having the drugs and b) working normally after being overactive?

Hi there,

Yes, one of the side-effects of Felimazole is vomiting and inappetence, but it is generally temporary. In your case, I would make an appointment with your vet to get her fully checked out straight away though. It's impossible for me to tell if her 'lethargy' is an indication that the medication is starting to work or a consequence of the vomiting or something else altogether.

Good luck!

Hi Jo365,

I'm sorry to hear your cat has been unwell, but it sounds like your vet is doing all the right things. The standard starting dose rate for Felimazole is 2.5mg twice daily for a cat as you've been correctly prescribed. I don't know how long she's been on the medication, but normally it takes two to three weeks to establish 'normal' thyroid levels again. Generally blood T4 levels are re-checked at 3, 6, 10 and 20 weeks after starting treatment and thereafter every 3 months with the dose adjusted according to her response. If you're concerned about her behaviour and inappetance then you need to speak further with your own vet as this may or may not be linked to the medications that she's having.

I hope that helps a little.

Zara The Vet
(www.zarathevet.com)

Hello,

My 16-year-old cat has just been diagnosed with hyperthyroidism. The vet has suggested putting him on a set of tablets one-a-day. I haven't picked up the tablets yet so don't know the name.
He is very skinny - looking like just skin and bones - and is off his food, just picking at it every now and then. He is also urinating in the house.
The vet said his blood levels showed a slight sign of kidney problem but not too much but I'm worried about the fact that he's not eating. He has become very lethargic and just sleeps all the time. I have read the tablets can reveal kidney problems. Do you think he has kidney disease?
He also has a strange squeaky noise when he breathes and is breathing through his mouth. The vet wasn't sure what was causing this as he doesn't do it all the time.
Can anyone help?

Ellie

Hi all,

I would really appreciate any help anyone can give as I'm worried sick about my dad's cat. The cat is almost 15 (female) and weighs 2.9kg. She was diagnosed with hyperthyroidism (I believe her hormone count was 91) about 7 weeks ago and put on a 3-week course of one 10mg tablet of felimazole daily. The vet stated that the tablets had 'little' effect, she did not gain any weight, but that hear heart rate went down from 200 to 180 bpm. She was then given a months course of 15mg once-daily felimazole. From the outset my dad has been wanting the cat to have surgery to cure the problem, after an initial period to stabilize the hormone level. The vet has never suggested that this won't be possible, and has simply said 'we need to get the heart rate down a little.'

I am now extremely concerned about what is going to happen to the cat as my dad is now saying that he is going to 'order' the vet to operate on the cat whether she is ready or not (yes, I know they won't do that if she isn't ready and have told him so) and that he is not going through with another course of tablets and blood test again. I would like a professional opinion as to how likely it is that the cat will be ready for surgery after completing this second dose, and what the criteria for being suitable for surgery are (such as the desired heart rate, and does the weight of the cat matter?). What would be the expected course of action if this second course of tablets has been ineffective? The cat is still very active, content and lively, though she is deaf and very thin (you can feel her spine in minute detail when you stroke her).

I would love some advice from anyone qualified please as I am driving myself crazy with worry and just want the best outcome possible for this cat.

Our 'stray' cat Millie is on felimazole a 2.5mg tab in the morning and a 5mg tab in the evening. She was such a sad skinny pathetic creature when we decided to take her in and look after her. We discovered that someone had moved away an left her! She is over 12 according to our vet and she had to have dental surgery but before they could anaesthetise her they had to get her heart rate down which was caused from a thyroid problem. It took about six weeks but finally she had the surgery and after about 5 months is a lovely happy healthy cat.. The thing we are worried about now is that she is always hankering and obsessing about food and when we give her food she eats very little. BUT she is putting on weight and it is very noticeable. Do you think her medication needs to be reduced?

Deleted (new message posted)



Edited 1 time(s). Last edit at 08/30/2012 03:37PM by Whiskerpuss.

Our cat Lulu is about 15 years old. She was diagnosed with hyperthyroid and put on 2 x 2.5mg Felimazole daily. After a further blood test this was incresed to 1 x 5mg and 1 x 2.5 mg daily. She has put on weight and appears to be in good general health and her coat looks really beautiful. Problem recently is though that she seems to be very itchy in lots of places. shehas licked the whiskers off one side of her face but these are growing back now, but we have just noticed a patch inside her back leg from which she has licked all the fur off and is nearly down to the skin. she has also had itchy ears, so we got some ear drops from Pets at Home store, these seemed to have the effect of just making her sleep for about 12 hours which was a bit worrying. Then she started to have red around her eyes, so we got her some eye drops for that. it seems to us that she has a bit of a funny cough / sneeze thing going on and I think she seems just like me when Ive got hayfever, or could all this be a reaction to the Felimazole? When the vet first put Lulu on these tablets she said to watch out for her getting an itchy face - this didnt happen until Lulu had been on the tablets for a while but it was after the dosage was increased. Any advice would be really appreciated.

We have given her a flea treatment regularly too so we dont think she is itching because of fleas.

Just as a useful tip for other cat lovers, we give Lulu her tablets tucked in the end of those chew stick things (Webbox make some) and she really likes then so its not normally a problem giving her a tablet twice a day.

I have deleted this post as I have made a new thread, later posts in this thread don't seem to be getting replies.



Edited 3 time(s). Last edit at 08/30/2012 03:36PM by Whiskerpuss.

I can see very exact and similar outcomes to cats that have been given Felimazole as has happened to my cat Pimms,now aged 13 yrs.She trots along nicely on 1.25 one tablet per day, She has just been advised to add one more per day( result is she is sick , so clearly I believe this is too much ) she began on two 2.5 per day in 2014. this dose made her fat and knocked her out she did not move.The vet lowered the dose and events took her to the 1.25 per day.The new vet who only has 2.5 in stock says she should take this. So since she was rescued she is on her fourth vet. Second one the best,due to a house move three and four happened.Does anyone know of a proper vet in suffolk or do I take her back to cambridgeshire. Remember your cat tells you.

My question is also regarding felimazole and vomiting. We started the treatment ( 2 times 2.5 mg) for my 13 years old cat about two weeks ago and everything seemed fine. Then two nights ago he began to throw up repeatedly. He throw up several times that night (after some vocalizing) mainly what seemed like saliva. In the morning I fed him without the pill, and he ate and seemed fine. But later on that evening he threw up again, and then again this rmorning (basically he threw up both meals I gave him). I haven't given him back his medication yet, as I worry he might get even worse, and would prefer to first talk to my vet (which takes us to tomorrow Monday). Is that a bad call? If it is the medicine that makes him throw up, would he still be throwing up two days after I stopped giving it to him?