I've taking a metformin twice a day sometimes i forget to take should i take it double?what is the best way to take it?

Metformin: Metformin is a generic medication that's available in several different forms but essentially short & long acting. Check out epocrates.Com & drugs.Com for more info. Metformin doesn't have an immediate effect on your sugar control so if your stomach can handle it (gi issues are most common side effect), ask your doc if you can take just a larger single daily dose (altho might be more expensive).

With meals: Take immediate release metformin with meals, twice a day. Time release should be taken as one larger dose with dinner. If you forget a dose, don't try to make it up -- instead, try not to forget.