Gavroche was diagnosed as hypothyroid in November 2010. He was put on meds and he's a whole different dog! He was on thyro-tabs (generic) first, and t was fine for a while then he got bad again - turns out they had put a smaller dose into the larger dose bottles (they ended up recalled). At that point I switched him to Soloxine name brand and haven't had an issue since. We've switched ALL the dogs at the clinic over to Soloxine, as we had more and more have issues with generics. So, I highly, HIGHLY recommend actual Soloxine. Also keep in mind the label they print to put on your bottle may say "Soloxine" but it could be a generic. The best thing to do is to ask or identify the pills. If you get the meds in the original packaging, it's an opaque brown bottle with a yellow label. The pills are kind of ovalish and are slightly shinier/denser than the generics.
Gavroche has been on the same dose the entire time - 0.5mg twice daily. Works AMAZING for him.