Originally Posted by tweetzer
Before the meds they seemed OK, but since the meds they are now showing the symptoms of hyperthyroid - drinking lots of water, howling, hungry all the time but losing weight, occasional vomiting.
Have they had any blood work as well as a urinalysis since the spring?
What about trying carbimazole in instead of methimazole to treat the hyperthyroidism? If you can get some weight back on your kitties, they may be good candidates for radioiodine therapy.
I'd also suggest finding another vet (maybe even a feline-only one) if at all possible. It's not a good sign that this one has just given up without even referring you to someone else who might have some fresh input on the situation.