Lactic acidosis is the biguanide related adverse effect of most concern, although serious, it is rare and may be minimized by strict adherence to contraindications. Acute reversible adverse effect are mainly of GI origin (discomfort, diarrhea, nausea, anorexia) and may be minimized by taking the drug with or after meals.
It may impair absorption of vitamin B
12 and folic acid.