Oral medication for diabetes

Oral diabetes medicine is prescribed for type II diabetes when lifestyle measures have not been successful in reducing sugar levels.
The choice of diabetic medication will be decided by your GP, and you must adhere closely to the prescribed doses and times.

The oral diabetic medicine can be prescribed alone, with other pills or even with insulin.

There are several classes of oral diabetes medicine, which are outlined below:

Biguanides (Metformin)

  • Reduces the amount of glucose released by your liver into your bloodstream
  • Also increases the sensitivity of your body's cells to insulin (so more glucose is absorbed into cells)
  • Often the first drug to be prescribed, especially if you are overweight
  • Is prescribed to be taken at the time of your meal
  • Sometimes causes nausea or mild diarrhoea, but these side effects are reduced if you start with a low dose and gradually build up

Sulphonylurea drugs

  • Stimulate secretion of insulin by the pancreas throughout the day to ensure the blood glucose level remains low
  • They can be prescribed alone or in combination with biguanides
  • Can cause weight gain as well as hypoglycaemia so you must have regular meals and avoid excess alcohol
  • You will be started on a low dose which may be titrated up
  • Examples include gliclazide, glimepiride and glipizide


  • Glinides have a similar action to sulphonylureas but they are not used commonly.
  • Examples include nateglinide and repaglinide


  • Increases the sensitivity of your body's cells to insulin (so more glucose is absorbed into cells)
  • They are not usually prescribed alone, but are useful in combination with metformin or a sulphonylurea
  • Contraindicated if you have heart failure, and need monitoring of your liver

Other oral medications


  • Delays the absorption of carbohydrates and so slows down the absorption of glucose in your diet
  • Useful if you cannot tolerate any of the other oral medications, but not used very often
  • Side effects include bloating, wind and diarrhoea

Incretin enhancers

  • Work by enhancing the effects of the enzyme incretin, which is released by you gut in response to food
  • You will need your liver to be monitored


  • If oral medications are not lowering your blood glucose sufficiently, you may started on insulin injections
  • Insulin can be given alone or in combination with tablets such as metformin or a sulphonylurea
  • If you are recommended insulin treatment, your doctor or practice nurse will give you detailed advice on how and when to use it - this is outlined on the next page
  • Weight gain is the main side effect, but hypoglycaemia can also occur


  • A new injectable treatment, which works in a similar way to the body's natural hormone glucagon-like peptide-1 (GLP-1)
  • Stimulates insulin release and also prevents the secretion of glucagon (hormone which increases blood glucose)
  • Alternative treatment to insulin, especially if you are overweight
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