hyperthyroidism

My sister's cat just got his yearly check-up...He is 7 years old.  He has lost 2 oz. since last year.  The regular blood test showed that he is borderline hyperthyroidism and was told to come back in 3 months to check.  Is there anything she can do now to help the thyroid?  If it does get worse, is there medication to treat this in cats? Thank you!

[Aleda M Cheng, D.V.M., C.V.A]

There is really nothing over the counter that will help your cat with hyperthyroidism. Since hyperthyroid disease is caused by the thyroid gland which is over producing thyroxine, you can't give supplements that will support the thyroid since it needs to be surpressed.  

There are very good therapies for hyperthyroid disease.  Specific Chinese herbal formulas can address early thyroid disease, and although they usually do not change the blood levels of thyroxine, they can be used successfully to control symptoms of hyperactivity and voracious appetite that occurs with hyperthyroid.  

For later and more severe thyroid disease the medication Tapazole, (a daily oral medication) is used to lower thyroxine levels, or, for outright cure,  injectable Iodine 131 (radioactive iodine) is used to selectively destroy the over producing thyroid tissue.  The iodine 131 treatment requires an injection or two and a brief hospital stay.