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Fact sheet: Medications for the treatment of type 2 diabetes

Created: ; Last Update: May 24, 2013.

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Type 2 diabetes is a complex illness that can cause somewhat different symptoms in every individual person. For some, life will hardly have to change after the diagnosis: losing just a little weight and doing a bit more exercise is enough to get their diabetes under control. Medicines might not even come into the picture. But other people with type 2 diabetes will face lots of decisions about taking medicine.

If you have type 2 diabetes, you are at higher risk of having a heart attack or a stroke, especially if you also have high blood pressure (hypertension). You might have problems with your feet, eyes or kidneys. Depending on your age, the particular set of health problems you have, and your general living conditions, different medications and target blood sugar levels could be important for you.

Whichever treatments you are using, the key to managing your diabetes is a good understanding of your own condition and what you can do on your own to protect your health. It is also important to have the support of a doctor and a team of specialists, for example a dietician, or a diabetes or foot care specialist. Ideally they will work closely with you to help you with your individual condition and finely tune the medications you need. In this fact sheet we explain the different medications that are often used when people have type 2 diabetes.

What is type 2 diabetes?

Diabetes is a metabolic disorder. The metabolism is the body’s system for transforming what we eat and drink into energy our bodies can use. Insulin is essential for our metabolism to work properly.

Insulin is a hormone (chemical messenger) that works in the body like a key to let sugar from the blood into our tissues and cells. If our insulin metabolism does not work properly, we cannot use up the glucose (sugar) in our blood. As a result, there is too much glucose in the blood. This is called hyperglycemia.

There are two main types of diabetes. In type 1 diabetes, the body usually cannot produce insulin at all anymore. Because this condition typically already starts in childhood or adolescence, it used to be called “juvenile diabetes”. In people who have type 1 diabetes, their pancreas is damaged and cannot produce any insulin, or only far too little.

Type 2 diabetes, also commonly called “adult-onset” diabetes, is different. Here the pancreas is still producing quite a lot of insulin at first, but it ends up not covering the body’s needs as it no longer has the effect it should on the body’s tissues and cells. The medical term for what is happening is “insulin resistance”. It is not clear why this problem develops. Being overweight and not getting enough exercise is definitely part of the problem, but it is not known exactly why.

You can learn more about insulin, metabolism and how it all works together in our fact sheet and article.

What can reduce the risk of complications from type 2 diabetes?

There are some changes you could make to your lifestyle that can protect your health and prevent harm if you have type 2 diabetes. Quitting smoking, losing weight and becoming more physically active can all make a difference – even small improvements count. You can read more about the benefits of weight loss and becoming more active here. It is even possible for some people to control their type 2 diabetes with these lifestyle changes alone.

This will not always be enough, however. People who have type 2 diabetes are at higher risk of heart and blood vessel problems like heart attacks, stroke and problems with blood circulation in their legs and feet (peripheral vascular disease). These are called the macrovascular complications of diabetes. “Macrovascular” means that it is the large blood vessels that are affected. People who also have high blood pressure (hypertension) are at particular risk.

Having far too much glucose in the bloodstream over many years can damage small blood vessels in the eyes, nerves and kidneys. These are so-called microvascular complications of diabetes. “Microvascular” means that it is the small blood vessels that are affected. Examples of such complications include damage to the retina of the eyes (retinopathy), nerves (neuropathy) and kidneys (nephropathy). You can read more about the long-term risks of type 2 diabetes here. The older you are, the lower your risk of microvascular damage is.

Depending on what symptoms and illnesses you have, different medications might be considered for different risks and complications. The main medications that can reduce the risk of life-threatening macrovascular complications of type 2 diabetes are:

  • Antihypertensive (blood-pressure-lowering) medications for people with high blood pressure. Many people who are older and have type 2 diabetes also have hypertension;
  • Low doses of acetylsalicylic acid (ASA, the active ingredient in, for example, Aspirin) taken every day to reduce the risk of blood clots that can cause heart attacks and strokes;
  • Statins, which lower cholesterol levels. One of the statins, simvastatin, has been shown to reduce the number of people with diabetes who die from heart disease – whether or not their cholesterol levels are high. You can read more about the research on different statins here.

All of these medications can cause adverse effects, so it is important to talk to your doctor about taking them. This is even true for drugs like ASA that you can get without a prescription.

If you have one or more of the complications of type 2 diabetes, such as retina damage, other treatments might be needed for those conditions specifically.

Some people who are overweight and have type 2 diabetes also use medications to try to lose weight. However, these also have adverse effects, and losing weight this way does not guarantee that your blood pressure and other risk factors will be reduced. Unlike losing weight with lifestyle changes, these medications usually do not help keep the weight off in the long term either.

There are also other medications that are used to try to prevent long-term microvascular damage to the eyes and kidneys associated with type 2 diabetes. These medications (antidiabetics) aim to reduce high blood sugar levels (hyperglycemia). The different antidiabetics are described below.

What happens if my blood sugar levels are higher than normal?

Again, this will depend on your age and your health. For example, if you are only 40 years old, even slightly higher blood sugar levels can cause damage over the years. On the other hand, many older people with type 2 diabetes have higher blood sugar levels that do not cause any symptoms and do no harm in the longer term, either. They often have other risk factors that are more of a priority, such as high blood pressure that is increasing their risk of a heart attack or stroke.

However, other people have health problems directly affected by high blood sugar levels, such as diabetes-related retina damage or kidney disease. For them, controlling blood sugar levels can be essential. Sometimes blood sugar levels are so high that there is no choice but to use medications to try to control them.

If you have high blood sugar levels (hyperglycemia), it means that there is too much glucose (sugar) in your bloodstream that cannot get into the cells in the normal way. Hyperglycemia can cause a lot of symptoms, like tiredness, needing to pass water a lot, and thirst. You can read about these symptoms in detail here.

Can the results of a glucose test tell me for certain whether I need glucose-lowering drugs?

If your blood sugar levels are so high that it is causing typical symptoms, you will probably also have high sugar levels in your urine. In Germany, you can get simple test strips from your doctor or pharmacist to test for glucose in your urine. There are also ways to measure the level of glucose in your blood. You can learn how to use these tests properly in a diabetes education program. Researchers are still studying what kinds of tests benefit different people with type 2 diabetes. When answers are available, we will report on them.

It is completely normal for our blood sugar levels to go up and down a little during the day. For example, they go up after eating and down during physical exercise. This also happens in people who do not have diabetes, but the fluctuations are much smaller. Blood sugar levels are affected by what and how much you eat and how much energy you use up. To get an idea of whether your blood sugar levels are too high on average, the HbA1c level (glycated hemoglobin) in your blood is measured. HbA1c is a part of the red pigment in your blood called hemoglobin that glucose molecules can bind to. The HbA1c level describes what percentage of hemoglobin has glucose attached to it.

Unfortunately, HbA1c measurement can differ from laboratory to laboratory. This means that your HbA1c level not only depends on your average blood sugar level, but also on the laboratory that analyses your blood. Still, it is safe to say that people who do not have diabetes usually have an HbA1c below 6%. The target HbA1c level that people with type 2 diabetes should try to reach depends on a lot of factors, and different experts set very different targets. However, an HbA1c over 8% is generally considered to be too high.

But whatever percentage is set as a target, it will mean different things for different people. Some people with type 2 diabetes will probably need to use glucose-lowering tablets, whereas others would not benefit much from that. In some cases, having an HbA1c over 8% may not be a problem. Because tablets always have adverse effects too, it is important that the risks and benefits are weighed up for each individual, and that their treatment goals are clearly defined before using them.

What types of tablets are used to control blood sugar levels?

People who have type 1 diabetes need to have insulin injections (they are “insulin-dependent”). But people with type 2 diabetes who need medications to control their blood sugar could use tablets (oral medications). Combinations of several glucose-lowering tablets are also possible, but it is not clear whether this may be more harmful than beneficial. Or you use injections plus tablets. The injections that can be used in type 2 diabetes are described below.

Which medications are most suitable for you will depend on your health and other things, such as whether one drug is more effective for you or has fewer adverse effects than another. Glucose-lowering medication does not always work for everyone. And what is best for you can change over time. That means that you and your doctor need to check how you are getting on from time to time, and adjust medications to try to get the best possible treatment outcomes for you.

Because high blood sugar levels are the main sign of type 2 diabetes, it might seem logical to use medication to lower the blood sugar levels first. This is not always necessary for everyone with type 2 diabetes, however. Only lowering blood sugar levels with drugs has not been shown to make a big difference to the major complications like heart disease and stroke, and these are the main issue for many people with diabetes – especially those who are older.

Secondly, glucose-lowering drugs also have adverse effects. For example, it is known that some drugs can increase heart problems. There are still many unanswered questions about the newer drugs. It is too soon to know what their long-term effects will be.

There are many oral medications for type 2 diabetes, and there are usually several brands of each drug available. You might know a medication by one of its brand names, but here we will discuss only the groups of drugs according to their chemical names. The chemical names for the medications are on the labels and in the product information that comes in the packet with your medication (package insert).

The most commonly used medications for type 2 diabetes (antidiabetics) are:

  • Metformin: This is a long-established drug for lowering blood sugar levels. It reduces the amount of glucose that your body makes. Weight gain and hypoglycemia are less likely with metformin than with sulfonylureas. But it can make you feel ill or cause diarrhea, especially if you take it on an empty stomach.
  • Sulfonylureas: These drugs have also been used for a long time, and include medications like glibenclamide and glimepiride. They help your body make more insulin. But some people gain weight when they use sulfonylureas, and others have allergic reactions to them.

The newer antidiabetic drugs include:

  • Glitazones (or thiazolidinediones): These drugs make cells in the body react better to insulin again. They can cause serious heart problems in some people, so a lot of research is being done on this.
  • Meglitinide derivatives: These include two different drugs, called nateglinide and repaglinide. They increase the amount of insulin your body makes. It is not exactly clear what adverse effects they may have.
  • Dipeptidyl peptidase-4 (DPP-4) inhibitors: DPP-4 inhibitors like sitagliptin and vildagliptin increase your body’s insulin production too. Their adverse effects are not fully known yet either.

As well as the adverse effects listed above, these drugs can all cause blood sugar levels to drop too low (hypoglycemia). It is important to be aware of this, as well as how to manage hypoglycemia, if you are using one of these drugs. You can find out more about the possible adverse effects of the drugs you are taking – or thinking of taking – by asking your doctor or pharmacist, or reading the information on the package insert.

Alpha-glucosidase inhibitors are another group of drugs for type 2 diabetes which, however, are only used very rarely nowadays. The main drug that is used from this group is called acarbose. It causes a lot of adverse effects, particularly wind, bloating and diarrhea. Compared to other options, it does not lower blood sugar levels as much.

There are a lot of trials going on to try to find out which of these drugs are better and safer for people with type 2 diabetes. We will be adding summaries of this research to our website in future. You can keep up-to-date with our new information on antidiabetic drugs by subscribing to our free newsletter here.

What are the injections that can be used for type 2 diabetes?

Injections for diabetes always used to mean insulin injected under the skin (subcutaneous injection). But people with type 2 diabetes can now choose between two kinds of drugs: insulin and incretin mimetics. Insulin is by far the more commonly used of these two options.

Insulin: There are many different types of insulin. It is used by all people with type 1 diabetes, and by some people with type 2 diabetes. Although people with both types of diabetes use insulin, the way it is used for type 2 diabetes is often quite different.

You can read more about insulin and the different types of insulin here. If you are considering using insulin analogues, which are slightly modified forms of what is called human insulin, you can read about them here.

With insulin, the main adverse effect is hypoglycemia, often called a “hypo”. This is when the blood sugar level drops too low. People often manage this by having a quick snack or sugary drink, but medication is needed to treat severe hypoglycemia..

If you need to use insulin, you will have to learn how to manage your insulin and balance your lifestyle, and what to do if you have an episode of hypoglycemia. This may seem difficult at first, but with some training, practice and support, people usually learn to manage their own insulin very well. Diabetes education programs can be very helpful.

Incretin mimetics: The only drug of this type is called exenatide. Exenatide is only suitable for people with type 2 diabetes, and it is only used together with other medications. It increases insulin production, reduces glucose production, slows the release of food from the stomach, and decreases appetite. Exenatide can lower blood sugar levels that are too high, and it can also help reduce weight a little. Its adverse effects include nausea, vomiting and diarrhea. You can read more about exenatide here.

Do I really need all these drugs, and are there good ways to help me manage my medications?

Using medication regularly over long periods of time is not easy. If you are diagnosed with type 2 diabetes or also have another chronic condition, it can be very hard to adjust to the idea of having to take medication for the rest of your life. It can be especially difficult to stay motivated to take medications regularly when you are not feeling sick.

With type 2 diabetes, there are a number of things you can do for your health that do not involve taking medications. In fact, losing even a bit of weight could be one of the best things you could do for your health if you have type 2 diabetes. But that too is easier said than done in practice.

Even a small increase in the amount of exercise you get can make a difference. Just walking a little more, for example, could have a positive effect on your health. We have put together information about what can help motivate people to lose weight here. If you are specifically interested increasing your physical activity despite having health problems like osteoarthritis, you can read about that here.

We have also put together some information to help you keep track of your medications and manage them better. You can read more about that here. If you are having trouble keeping on top of your medications, several things have been shown to help – especially keeping your regular appointments with your doctor. Learning more about your medications and simplifying your medication schedule as much as possible can also help.

Adjusting to having type 2 diabetes and managing it in your daily life can be a difficult challenge. But once you have learned how to manage your blood sugar levels and medications if you need to use them, your diabetes self-management can become a normal part of life and it does not have to limit your enjoyment of life. It is very important that you find a good doctor who takes the time to discuss all of the aspects of type 2 diabetes with you. One of your options is to join a “disease management program”. You can read more about these structured treatment options here.

Author: Institute for Quality and Efficiency in Health Care (IQWiG)


  • Bolen S, Feldman L, Vassy J, Wilson L, Yeh HC et al. Systematic review: comparative effectiveness and safety of oral medications for type 2 diabetes mellitus. Ann Intern Med 2007; 147: 386-399. [PubMed: 17638715]
  • Institute for Quality and Efficiency in Health Care (IQWiG). Evaluation of the effects of statins (with particular consideration of atorvastatin). Cologne: IQWiG. 2005. [Full text] [Informed Health Online summary]
  • Institute for Quality and Efficiency in Health Care (IQWiG). Rapid-acting insulin analogues for the treatment of diabetes mellitus type 2. Final report A05-04. Version 1.0. Cologne: IQWiG. December 2005. [Full text] [Informed Health Online summary] [PubMed: 23101062]
  • Institute for Quality and Efficiency in Health Care (IQWiG). Long-acting insulin analogues in the treatment of diabetes mellitus type 2. Final report A05-03. Version 1.1. Cologne: IQWiG. February 2009. [Executive summary] [Full text - in German] [Informed Health Online summary] [PubMed: 23101111]
  • Institute for Quality and Efficiency in Health Care (IQWiG). Benefit assessment of non-drug treatment strategies in patients with hypertension: weight reduction. Final report A05-21A. Version 1.0. Cologne: IQWiG. August 2006. [Executive summary] [Full text – in German] [Informed Health Online summary] [PubMed: 23101095]
  • Institute for Quality and Efficiency in Health Care (IQWiG). Insulin therapy. Informed Health Online article. Cologne: IQWiG. May 2007. [Full text]
  • Institute for Quality and Efficiency in Health Care (IQWiG). Evaluation of the therapeutic benefits and harms of Exenatide. Rapid report A05-23. Version 1.0. Cologne: IQWiG. August 2007. [Full text – in German] [Informed Health Online summary]
  • Institute for Quality and Efficiency in Health Care (IQWiG). Glitazones in the treatment of diabetes mellitus type 2. Preliminary report A05-05A. Version 1.0. Cologne: IQWiG. June 2008. [Full text – in German] [PubMed: 23101104]
  • Krumholz HM, Lee TH. Redefining quality - implications of recent trials. New Engl J Med 2008; 358: 2537-2539. [Full text] [PubMed: 18539915]
  • Richter B, Bandeira-Echtler E, Bergerhoff K, Lerch CL. Dipeptidyl peptidase-4 (DPP-4) inhibitors for type 2 diabetes mellitus. Cochrane Database of Systematic Reviews 2008, Issue 2. [Cochrane summary] [PubMed: 18425967]
  • Saenz A, Fernandez-Esteban I, Mataix A, Ausejo Seguar M, Roque i Figuls M et al. Metformin monotherapy for type 2 diabetes mellitus. Cochrane Database of Sys Rev 2013; (4): CD 002966. [Cochrane summary] [PubMed: 16034881]
  • Salpeter S, Greyber E, Pasternak G, Salpeter E. Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus. Cochrane Database of Systematic Reviews 2006, Issue 1. [Cochrane summary] [PubMed: 16437448]
© IQWiG (Institute for Quality and Efficiency in Health Care)
Bookshelf ID: NBK82135
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