Biguanides are a drug class comprised of only one drug called metformin. The exact mechanism of action of metformin has not yet been fully elucidated however it reduces glucose production by the liver and reduces the level of glucose in the blood. Metformin is now a generic drug available in various formulations.

• METFORMIN

  Tradename(s)	Glucophage® and Glucophage® XR, Fortamet®, Glumetza®, Riomet®, Diabex and Diabex XL, Diaformin and others
  Company(ies)	Bristol-Myers Squibb, Depomed Inc., Ranbaxy Labs, Andrx Labs LLC and several other generic manufacturers
  Available doses	500 mg, 750 mg, 850 mg and 1000 mg
  Dose per day	immediately after each meal except for slow release formulation which are taken once daily
  Side-effects	gastrointestinal effects and in rare cases lactic acidosis
  Elimination half-life	6.2 hours
  Metabolism	excreted unchanged in urine and does not undergo hepatic metabolism
  US patent status	generic
  US FDA status	approved March 1995
  EMEA status	approved - on the market since the 1950s
  Indication
  Metformin, as monotherapy, is indicated as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes. Metformin may be used concomitantly with a sulfonylurea or insulin to improve glycemic control in adults.
  Comments
  Metformin is the least expensive and one of the oldest drugs for type 2 diabetes. It is now a generic drug widely available in various formulations including newer slow-release formulations.