It sounds like she has hyperthyroidism? Your giving her tapazole/methimazole?
There are a few options you have.
Transdermal gel. You wipe a small amount on the skin on the inside of her ear. (Depends on how it's compounded and her dose on much you use)
Methimazole comes in a chewable form.
Pill pockets. They come sized for cats. It's a yummy (play-doh like) pocket that you put the oil in and mush it around and give it to her. They come in different flavored.
The first 2 will be a little more expensive than the little white bitter pills.
Last radioactive iodine therapy. It cost about $1,000-2,000.
It pretty much kills the thyroid.
Hyperthyroidism is an overactive thyroid. Causing weight loss, rapid heart rate, kidney issues, among other things.
If you do the radioactive iodine therapy and since it "kills" the thyroid she'd have to be on thyroid supplement. Soloxine, thyroxine.