Biguanides, adverse reaction

Metformin is a biguanide derivative that can normalize an elevated blood glucose level, provided that insulin is present. The mechanism underlying this effect is not completely understood. Decreased glucose release from the liver appears to play an essential part. Metformin does not increase release of insulin and therefore does not promote hyperinsulinemia. The risk of hypoglycemia is relatively less common. Triglyceride concentrations can decrease. Metformin has proved itself as a monotherapeutic in obese type II diabetics. It can be combined with other oral antidiabetics as well as insulin. Frequent adverse effects include anorexia, nausea, and diarrhea. Overproduction of lactic acid (lactate acidosis) is a rare, potentially fatal reaction. It is contraindicated in renal insuf ciency and therefore should be avoided in elderly patients. 

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