I hope someone who has had anything similar to this problem may be able to help. I have a 14 year old male cat who was diagnosed with hyperthyroidism last July. For the past 13 years (I have had this cat since his birth and I was 10. He is my baby!) my cat has had absolutely no health problems. I hadn't noticed anything abnormal about my cat, but friends and family who didn't see him everyday said he looked like he was losing weight. After being told this a few times I decided to take him to the vet. The vet did a pshyical exam and complete blood work which all came back normal with the exception of a very high thyroid reading. The vet then put him on Tapazole and since then my cat has been nothing but sick. About 2 weeks after starting the medication my cat had a mild siezure. I took him to an emergency vet that night, who gave him Phenabarbitol until we could get him to his regular vet the next morning. His regular vet said the seizure was due to his thyroid drastically dropping (he went from 10 to 6) and she reduced his dosage. On the Tapazole my cat was a completely different cat. He became paranoid and his hair was constantly dull and standing up on his back. Those are just a few of the changes. Anyway, he stayed that way until this past December when he really got bad. A few days before new year's eve my cat started vomiting and became severly dehydrated. He wouldn't eat, wouldn't drink and vomited at least 10 times a day. He went into the hospital over new year's was put on IV's and taken off of the Tapazole and since then he has become the cat he always was. He actually plays again, he runs, he hides under tables so he can grab people as they walk by, etc... We were supposed to take him back to the vet's office when he was better so she could recheck his thyroid and put him back on his medicine, but after seeing the difference I just don't think I can. His vet said in the begining that not having him on the medicine would probably result in death, but I don't know if I have the heart to put him back on it. So my question is; has anyone else had a cat with hyperthyroidism and any problems with the medications. This is my baby and I don't want to hurt him by making him take the medication, but I also don't want to hurt him or shorten his life by not giving him anything for this problem. Any suggestions would be welcome. I just don't know what to do. Thanks.