If the methadone is making you tired all the time, you should probably bring that up with your doc. When properly dosed you might go through a 'slow' period when first starting but that should fade (IME anyway) after several days or a week, maybe a little longer. I know when I was on it my initial dose was too high and I was always groggy, but after having the dose lowered a bit everything was great. All the benefits of methadone (only dosing once a day, not very expensive) with few side-effects unless the dosage was toyed with. Which I don't recommend doing! Anyway, good luck!

L