Today our cat Brynna is in for dental surgery, extracting a rotten tooth. She turns 16 next month so she's pretty old for this, but it's still not a high-risk operation.
We also discussed a thyroidectomy, but that's higher-risk, and also very high cost, and brings with it the likelihood of increasing her kidney dysfunction. Its primary purpose would be to avoid having to give her pills; it's hard to medicate a cat since you can't catch them regularly enough when it's several times a day, and particularly one like Brynna who doesn't eat reliably, even if you sneak something into her food.
Instead, however, we're going to be getting her a cream that we apply twice daily in her ear (should be a lot easier than a pill!) that'll give her the thyroid suppression transdermally. This will provide a more steady flow of the drug for better regulation, should last longer for less times of high blood pressure, and avoid the stomach upset effects that the orally administered pills cause.