Medicines for type 2 diabetes

Also called anti-diabetic medicines

When you have type 2 diabetes (mate huka), your body does not make enough insulin or does not use it well enough. This leads to raised blood glucose (sugar) levels. When used with a healthy diet and exercise, diabetes medicine can effectively lower your blood glucose levels.

The main aim of treatment for diabetes is to reduce your risk of getting complications from diabetes by controlling your blood glucose levels. Having constantly raised blood glucose levels damages your blood vessels and nerves, leading to problems affecting your kidneys, feet and eyes. Your risk of stroke and heart attacks also increases. 

On this page, you can find the following information:

When are medicines used for type 2 diabetes?

Diabetes medicines are used to lower blood glucose levels when lifestyle changes such as diet and exercise have not been successful. Sometimes medicines are prescribed at first diagnosis if blood glucose levels are very high. You need to keep eating a healthy balanced diet, managing your weight and exercising regularly even when you are taking diabetes medicines. Watch a video to find out more: What you need to know about diabetes medications. 

Examples of diabetes medicines

There are a variety of medicines used to treat type 2 diabetes – most are available as tablets. The most commonly prescribed medicine is metformin. Some people also need insulin, which is available as an injection only.

Your diabetes may be well controlled on one medicine alone, or you may need a combination of medicines. Some people need 
a combination of tablets and insulin injection. Every person’s care plan is different and your healthcare provider will work with you to find out the best treatment plan for you. 

Diabetes medication

Most people with type 2 diabetes are started on metformin tablets.

  • Metformin works by improving your body's response to the insulin you naturally make.
  • It also decreases the amount of glucose made by your liver and increases the use of glucose by your muscles.
  • It is usually taken 2 times a day, with or after food. 
  • A side effect of metformin may be diarrhoea (runny poos), but this improves when it is taken with food.
  • Read more about metformin.
Other diabetes medicines

These medicines are usually prescribed if you are unable to take metformin or if your blood glucose levels have not been lowered successfully with metformin alone. Combining medicines can be a more effective way to lower your blood glucose levels. Click on the links below to find out more about each medicine:


Insulin injections are used when your blood glucose levels have not been lowered successfully with tablets. This is usually when your body no longer produces enough insulin. Insulin medicine is very similar to natural human insulin. Insulin is given as an injection under your skin. It cannot be given as tablets because enzymes in your stomach destroy it. There are different types of insulin. Read more about insulin.

What are the considerations when choosing medicines for type 2 diabetes?

Here are some of the things you and your doctor may consider when deciding on the best treatment for you.

Your blood glucose levels: Most people with type 2 diabetes are started on metformin tablets. If you are unable to take metformin because of side effects or other reasons, your doctor will consider starting you on other medicines. If your blood glucose level is not successfully lowered with metformin alone, your doctor may add in other medicines that act in different ways to lower your blood glucose levels.

Other health conditions: Some conditions you might have along with diabetes can affect how well your medicines control your blood glucose, including:

  • obesity
  • high blood pressure
  • high cholesterol
  • heart disease
  • kidney disease.

Funding: Some newer diabetes medicines such as empagliflozin and vildagliptin are funded for people with diabetes if they meet certain criteria (also called a special authority). Read more about a special authority

Side effects: When deciding on the best medicine for you, discuss with your healthcare provider the possible side effects of the medicine and how these are likely to affect you or your lifestyle, such as weight gain or the risk of hypoglycaemia (low blood glucose).

Questions to ask about your diabetes medicines

Understanding what your medicines are for and how to take them helps ensure you get the most benefit from them. Here are some questions that you might ask your doctor, pharmacist or nurse:  

  • What is the name of my medicine and what does it do?
  • What is the strength (eg, how many milligrams)? 
  • How much should I take for each dose?
  • At what times of day should I take my medicine?
  • Am I supposed to take it with something to eat?
  • What should I do if I forget to take a dose?
  • What should I do if I miss a meal?
  • Are there any side effects to watch out for?
  • When should I expect the medicine to start working, and how will I know if it is?
  • Can my diabetes medicine cause low blood glucose?
  • What should I do if my blood glucose is too low?
  • What should I do if I feel better and don't want to keep taking it?
  • Is it okay to take with other medicines, alcohol or natural remedies?
  • What should I do if it doesn't seem to work?
  • What should I do if Í am having an operation?

Learn more

Return to the main diabetes page.


  1. Treatment of diabetes NZ Formulary
  2. Managing patients with type 2 diabetes – from lifestyle to insulin BPAC, 2015
  3. Vildagliptin – a new treatment for type 2 diabetes BPAC, 2018
  4. Management of type 2 diabetes NZ Primary Care Handbook, 2012
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 16 Feb 2021