This is a tricky question ~ some doctors will not recommend longterm (indefinite) use of ATDs, because of the liver issues. There are actually two issues. The first comes up when the patient begins taking ATDs, and if it happens, the patient stops taking them. You are obviously not one who had immediate/dramatic changes in your liver enzymes from taking ATDs. The longterm issue is a little more complex. Our liver gets "filled up" with byproducts from all the meds we take over our lifetime, and so as we get older, we need to be even more careful about the meds we take, to avoid building up toxicity and taxing the liver. We also need to be aware that, as we age, it is more likely that MORE meds will be added to our daily regimen, so lessening the amount of meds we take is better than adding to it, if we have a choice.
The replacement hormone we take after we do either RAI or surgery is NOT processed through the liver and does not elevate toxicity, because it is chemically identical to the substance our thyroid would produce if it could, which does not tax the liver in "regular" people or in us.
There are LOTS of people who did not gain significant amounts of weight after RAI or surgery. Being well regulated prior to treatment will definitely help.
