| Radioactive iodine | Anti-thyroidal drugs e.g. methimazole, carbimazole | Low-iodine diet | Surgical removal of the thyroid glands | |
|---|---|---|---|---|
| Initial cost | Higher | Lower | Lower | Higher |
| Long term cost | Lower | Higher - life-long medication & regular blood tests | Moderate - life-long medication & regular blood tests | Low |
| Specific Requirements | Isolation in licensed facility for 5-7 days | None | Indoor only cat, ability to control dietary intake of cat | Requires surgeon experienced in technique |
| Considered a definitive treatment (I.e. possibility for all abnormal tissue to be removed or destroyed) | Yes | No | No | Yes |
| Ease of use for owner | After treatment must be kept indoors for a further 2 weeks thereafter easy. | Ability to medicate the cat either with tablets or ointment | Easy if they like the food | Easy. May need short period of medical therapy to stabilise prior to surgery and short period of medical therapy for pain relief after surgery |
| Anaesthesia required | No. Some cats require light sedation | No | No | Yes |
| Time to normalising thyroid | Days to weeks | 2-4 weeks | 6-8 weeks | Within 1-2 days |
| Hospitalisation required | Yes 5-7 days, then indoors for 2 weeks. | No | No | Yes, 2-3 days |
| Risk of low blood calcium | No | No | No | Yes, if both glands removed |
| Possible disadvantages or complications | Hypothyroidism or persistent hyperthyroidism possible (2% of treated cats) | Owners must medicate their cat daily. Mild side effects are common. Severe side effects are possible. Hypothyroidism can occur. Increased risk of transition from thyroid adenoma to thyroid carcinoma | Cats not liking the food, persistent hyperthyroidism is relatively common, can be difficult if multiple cats in the household | Recurrence of disease is possible after removal of one or both glands. Hypothyroidism is possible (low thyroid levels) |
