My 12 years old cat just got diagnosed with hyperthyroidism. He hasn't shown any symptoms except increased appetite. I decided to give him ear gel for now (he has sensitive stomach) while doing more research about other treatment options. Any experience with medications (oral, topical, side effects, etc.) or radioiodine treatment? Do medication lose effects after some years? I thought of trying radioiodine, but I saw some reviews that some cats died soon after the treatment. The facility recommended by our vet has many good reviews but also many cats needed IV after being discharged. I'd like to hear your experiences, opinions, and advice. Thanks in advance.