Cat on Methimazole, went slightly hypo, dose adjusted now *Very* hyperthyroid again

mom2millie

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hi,

My cat Millie was diagnosed hyperthyroid a couple of months ago.  I was told she was very hyperthyroid but I never got the T4 number.

Put on liquid Methimazole .5ml 2x/day.

Was slightly hypothyroid after 3-4 weeks (T4 at 20) dose altered to .4ml 2x/day

Now a few days ago, after her second & most recent blood test, I am told she is very hyperthyroid, I think the vet said the T4 was about 184 or close to that; very high anyways.  He said that 55 is the upper limit of normal, from what I recall.

I normally use the syringe and squeeze the liquid right in her mouth.  I never missed a dose and if I gave her the dose a bit late, I adjusted the timing slightly for the next couple of doses until I weaned things back to the regular time.

Is it possible because my cat is small (5.4-5.6 lbs) that she is really sensitive to a change in the dose?

Does methimazole's dosage effectiveness dependent on weight?

Other than maybe occasionally a little of the liquid going just on the outside of her mouth, I don't know why she went hyper like this.

Is methimazole supposed to be given to cats on an empty stomach?   I was not told to do it this way and I'm not sure my cat would go without her dry food at night.
 

nurseangel

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Hi, my beloved Garfield was on this medication and I wish I could answer your questions.  I know thyroid medicine can be tricky in people and seems more often than not to require some tweaking until the proper lab values are achieved.  I suspect it's probably pretty much the same for animals.  My advice would be to contact the vet with your concerns.  You are doing a wonderful job in taking care of Millie.  I hope the vet gets her dose adjusted soon; I could tell that Garfield felt better and seemed a happier cat after we started giving the medicine to him.  We were fortunate that the initial dose prescribed worked well.

I wish Millie the best of health.  Please keep us posted.  
 
 
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