Medication for type 2 diabetes

People with type 2 diabetes are often given medications including insulin to help manager their blood glucose levels. Most of these medications are in the form of tablets, but some are given by injection. Tablets or injections are intended to be used in conjunction with healthy eating and regular physical activity, not as a substitute.

Diabetes tablets are not an oral form of insulin.Speak with your doctor or pharmacist if you experience any problems. An alternative medication is usually available.

All people with diabetes need to check their glucose levels on a regular basis. When taking medication, you may need to check your glucose levels more often to keep you safe and to ensure the medication is having the desired effect.

Classes of medications

There are seven classes of medicines used to treat type 2 diabetes:

  • Biguanides
  • Sulphonylureas
  • Thiazolidinediones (Glitazones)
  • Alpha-glucosidase Inhibitors.
  • Dipeptidyl peptidase 4 (DPP4) inhibitors
  • Incretin mimetics
  • Sodium-glucose transporter (SGLT2) inhibitors

Your doctor will talk to you about which tablets are right for you, when to take your tablets and how much to take. Your doctor can also tell you about any possible side effects. You should speak to your doctor or pharmacist if you experience any problems.



Points to remember about biguanides

  • This group of insulin tablets helps to lower blood glucose levels by reducing the amount of stored glucose released by the liver, slowing the absorption of glucose from the intestine, and helping the body to become more sensitive to insulin so that your own insulin works better
  • They need to be started at a low dose and increased slowly
  • Metformin is often prescribed as the first diabetes tablet for people with type 2 diabetes who are overweight. It generally doesn’t lead to weight gain and may help to manage weight
  • Type 2 diabetes is progressive and your doctor may need to increase the dose over time
  • Metformin may need to be combined with the sulphonylurea or other classes of tablets and/or insulin
  • Metformin by itself does not cause hypoglycaemia (low blood glucose or ‘hypo’) but may contribute to hypoglycaemia when used in conjunction with a sulphonylurea tablet or insulin.

Some Brand Names
METFORMIN : Diabex®, Diaformin®, Formet®, Metforbell®, Glucohexal®, Glucomet®, Glucophage®, Genrx metformin®, Genepharm metformin®
METFORMIN ER : Diabex®,Diaformin XR®, Metex XR®

Not to be taken by:

  • people with severe liver, kidney or heart disease. Metformin may need to be stopped before surgery or procedures that require injecting a radio-opaque dye such as a coronary angiogram. Always check with your doctor.


This group of insulin tablets stimulates the pancreas to produce more insulin.

Points to remember about sulphonylureas

  • Sulphonylureas lower blood glucose levels by stimulating the pancreas to release more insulin
  • They can cause hypoglycaemia. Be sure to discuss this with your doctor or health professional
  • Other possible side effects include:: weight gain, skin rashes, gastric upsets, jaundice
  • Type 2 diabetes is progressive and your doctor may need to increase the dose over time.
  • Sulphonylureas may need to be combined with metformin tablets.

Some Brand Names
GLICLAZIDE : Glyade®, Mellihexal®, Nidem®, Genrx Gliclazide®
GLICLAZIDE ER : Diamicron MR®, Glyade MR®, Oziclide MR®
GLIBENCLAMIDE : Daonil®, Glimel®
GLIPIZIDE : Melizide®, Minidiab®
GLIMEPIRIDE : Amaryl®, Dimirel®, Aylide®, Diapride®, Gilmepiride Sandoz®

When to take: before with meals.
Not to be taken by: women who are pregnant or breast-feeding. On a rare occasion a doctor may prescribe them.

Thiazolidinediones (glitazones)


Points to remember about thiazolidinediones (glitazones)

  • They help to lower blood glucose levels by increasing the effect of your own insulin, especially on muscle and fat cells, i.e. they improve insulin resistance
  • Their effect is slow, taking days to weeks to begin working and one to two months for their full effect
  • They work well together with some of the other diabetes tablets
  • Taken on their own, they do not cause hypoglycaemia, but this can occur when they are taken with a sulphonylurea.
  • They should not be taken by people who have liver disease.
  • A side effect is weight gain. Fat is moved from areas where it is bad for your health (around the tummy) to other areas such as the top of the thighs, where you still may not want it but it is not as harmful to your health.
  • Another side effect is fluid accumulation and glitazones should generally be avoided by people with heart failure. Discuss this with your doctor whether or not they are right for you.
  • It is recommended that regular checks of liver function are done particularly in the first year of treatment with these tablets. Your doctor will need to discuss this with you when starting your treatment.

Some Brand Names

Not to be taken by: women who are pregnant or breast-feeding or if liver disease is present.

Alpha Glucosidase Inhibitors

Chemical name: ACARBOSE

Points to remember about alpha glucosidase inhibitors

  • They help to slow down the digestion and absorption of certain dietary carbohydrates in the stomach (intestine). Taken on their own, they don’t cause hypoglycaemia.
  • If hypoglycaemia occurs, due to another diabetes tablet you may be taking, it must be treated with pure glucose such as glucose tablets, gel or Lucozade. Absorption of other forms of carbohydrate may be affected by Glucobay.
  • Side effects include flatulence (wind), bloating and diarrhoea.
  • They can be taken together with other classes of medication including insulin.
  • They need to be started at low doses and increased slowly to reduce side effects.

Some brand names

When to take: They need to be taken just before eating.

Dosage: once or twice daily. The dosage may differ for individuals so ONLY take the dosage prescribed by YOUR doctor.

Not to be taken by: women who are pregnant or breast-feeding.

DPP-4 inhibitors


Points to remember about DPP-4 inhibitors

  • They work by inhibiting the enzyme DPP-4. This enhances the levels of active incretin hormones which act to lower blood glucose levels by increasing insulin secretion and decreasing glucagon secretion (a hormone that has the opposite effect of insulin by increasing blood glucose levels).
  • By themselves, they are unlikely to cause hypoglycaemia because they do not work when blood glucose levels are low.

Some brand names

Not to be taken by:
They should not be used if you are under 18 years of age, are pregnant or intend to become pregnant, while breastfeeding or if planning to breastfeed, or for the management of type 1 diabetes or diabetic ketoacidosis. If you have kidney or liver problems, your doctor may prescribe lower doses.

Incretin mimetics


Points to remember about incretin mimetics:

  • They are given by injection under the skin.
  • Your doctor or diabetes educator will help you learn how to do this.
  • They are not a substitute for insulin,
  • Byetta® is used with metformin or a sulfonylurea. It may also be used with a combination of both metformin and a sulfonylurea It can also be used in combination with a long acting insulin and metformin.
  • Victoza® is used with metformin or a sulfonylurea. It may also be used with a combination of both metformin and a sulfonylurea.
  • Victoza® is not approved for use with insulin.
  • Byetta® is given twice daily with a pre-filled pen in relation to meals
  • Bydureon® is given once a week. It comes in a kit that contains a powder that must be mixed with a diluent (solvent) before use
  • Victoza® is given once daily with a pre-filled pen not in relation to meals
  • Needles are not included with the pen.

Some brand names
EXENATIDE : Byetta®, Bydureon®

Not to be taken by: people with type 1 diabetes

Sodium-glucose transporter (SGLT2) inhibitors


Points to remember about SGLT2 inhibitors:

  • Take with or without food
  • Might help with weight loss
  • Might help lower blood pressure
  • Taken on their own, they do not cause hypoglycaemia (low blood glucose)
  • Side effects can include an increase in urinary tract infections (UTIs), genital thrush and increased urination
  • Dose needs to be adjusted for people with moderate kidney problems
  • Dose needs to be adjusted for people over the age of 75 years

Some brand names

Not to be taken by: people with severe kidney problems or if you are under 18 years of age.


At some stage your doctor may decide to add a second or even a third type of tablet to maintain your blood glucose levels. For example, metformin plus a sulphonylurea is a common combination.
As an alternative to taking two separate tablets there is currently three products that combine two medications into a single tablet:

Chemical name:

  • Metformin/glibenclamide
  • Metformin/Rosiglitazone
  • Metformin/Sitagliptin
  • Metformin/Vildagliptin

Will I ever need to go on to insulin?

Type 2 diabetes is a progressive condition with decreasing insulin production over time. As all the tablets need enough insulin to work, when a person with diabetes is no longer making enough of their own insulin, they will need insulin treatment to manage their blood glucose levels, sometimes with tablets as well. This can happen quite quickly but more often occurs in about 50% of people within 10 years of being diagnosed. Insulin is very safe and can be used in women who are pregnant and breast-feeding. It is a good medication for treating people with diabetes and, when used properly, can prevent many potential complications.