I am sorry to hear this about Gatsby. My RB tux, Tex, was hyperthyroid. The medication worked really well for years.

I did consider the treatment, but it was 5 years ago, and it was somewhat 'new' and since the meds worked, well I went with that option. Today, presented with the same dx? I would do the treatment.

Good luck with it all, and special tuxie pets to Gatsby.