All sulphonylureas can cause hypoglycaemia . Renal insufficiency may require dose reduction. Biguanides Biguanides are useful as first-time drug treatment in the obese. Metformin must not be used in patients with impaired renal function , septic shock or during major surgery, because of the risk of lactic acidosis. If creatinine rises, stop the drug.
Gastrointestinal intolerance can also occur.
They are useful particularly in those with normal fasting glucose levels. Usual dose 50-100 mg at the beginning of main meals. Combination therapy Metformin and a sulphonylurea may be used in combination when treatment goals are not achieved with either agent alone or when there are clinical reasons for not using insulin. Combinations of small doses may also be used to avoid side-effects of either agent. Glucosidase inhibitors may also be used in conjunction with oral hypoglycaemic drugs.