It’s main use is in obese pt with NIDDM either alone or in combination with a sulfonylureas.Metformin has an anorexic effect which helps to reduce wt in the obese. Less used now a days .They causes sever lactic acidosis in pt with renal disease, hepatic disease,cardiopulmonary dysfunction,alcoholism.They also cause diarrhoea with vit deficiency.
Mechanism of action:
[A]The activity of biguanide is not dependent on the presence of functioning pancreatic β cells for their hypoglycemia action.
[B]They are appropriately termed ‘englycemic agents’.Because they cause hypoglycemia in hyperglycemia condition.The effect on normal blood glucose level is more or less zero.
They act by:
1) Direct stimulation of glycolysis in tissue which increase glucose removal from blood.
2) Slowing of glucose absorption from gut.
3) Increasing insulin binding to insulin receptor.
4) ↓ Plasma glucogon level.
Indications of biguanides/Metformin:
1) Type II.
2) Obese patient.
3) When Sulfonylurease fail.
Adverse effects Biguanide/Metformin:
- Abdominal pain.
- Lactic acidosis.
- Pruritus and urticaria.
- Derease Vitamin-B12 absorption.