Other medications

The main classes of antidiabetic medication other than insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. include the below.

Biguanides

The only available drug in this class is metformin. It improves the sensitivity of the body to insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels., mainly in the liverA large abdominal organ that has many important roles including the production of bile and clotting factors, detoxification, and the metabolism of proteins, carbohydrates and fats. and muscleTissue made up of cells that can contract to bring about movement. but also in fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. tissue.

Unlike many other antidiabetic medications, metformin does not cause weight gain. In fact, it may actually promote a small amount of weight loss. It also seems to have protective effects on the heart, as well as lowering glucoseA simple sugar that is an important source of energy in the body. levels.[1]

While many antidiabetic medications carry the risk of lowering bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. too much, causing hypoglycaemia, this is very rare with metformin. This is because this drug does not increase insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. secretion.[2]

Metformin may have some gastrointestinal side-effects, which can be reduced by taking it with meals and avoiding high doses when starting treatment.

This drug should not be taken if you have any liverA large abdominal organ that has many important roles including the production of bile and clotting factors, detoxification, and the metabolism of proteins, carbohydrates and fats. or kidney problems, or any conditions that might increase the risk of kidney problems - such as dehydrationWater deficiency in the body. or severe infectionInvasion by organisms that may be harmful, for example bacteria or parasites..[3] It should also be avoided in people who drink a lot of alcohol.[2]

Sulphonylureas

This group of medications acts by stimulating insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. release from the pancreas. The drugs in this class differ in how effective they are and in how long their effects last.[2]

Unfortunately, sulphonylureas can cause weight gain, which may exacerbate diabetes. Because of this, these drugs are best taken by people who are not obese.

Another important side-effect is the risk of lowering bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. sugar too much, resulting in hypoglycaemia. This is more likely with longer-acting medications.[2]

Alpha-glucosidase inhibitors

These medications, which include the drug acarbose, act by delaying the body's absorption of carbohydratesA group of compounds that are an important energy source, including sugars and starch. from food. Because of this, they should be taken with every meal. Side effects include flatulence, abdominal bloating and diarrhoeaWhen bowel evacuation happens more often than usual, or where the faeces are abnormally liquid..[2]

Thiazolidinediones

Thiazolidinediones, which are often abbreviated to TZDs, are a newer class of drugs that increase the body's sensitivity to insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels..  Other beneficial effects may include redistributing body fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. away from the abdomenThe part of the body that contains the stomach, intestines, liver, gallbladder and other organs., although unfortunately they appear to increase overall body fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body..

They are usually given on top of metformin or a sulphonylurea, when either of these is not enough to control glucoseA simple sugar that is an important source of energy in the body. levels alone. Like metformin, they do not increase insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. levels and so do not cause hypoglycaemiaLow blood glucose levels..[2]

Side effects of thiazolidinediones include salt and water retention. They should not be taken by people who have liverA large abdominal organ that has many important roles including the production of bile and clotting factors, detoxification, and the metabolism of proteins, carbohydrates and fats. or heart disease.[2]

Meglitinides

Repaglinide directly stimulates the release of insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. from the pancreas and should be taken just before eating. Nateglinide acts in a similar way.[1]

Both medications are taken orally. They seem to be as effective as metformin, and may be helpful in people who are unable to take metformin. However, these are new drugs and little is known at this stage about their effects in the long term.[4]

Pramlintide

Pramlintide is given by subcutaneous injection, and can be used in both type 1 and type 2 diabetes. Its effects include a reduction in bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. at mealtimes, a fall in HbA1cAn abbreviation for glycated haemoglobin, a measure of how well glucose levels have been controlled over the previous three months or so in a person with diabetes. It is expressed as a percentage. and a fall in the hormoneA substance produced by a gland in one part of the body and carried by the blood to the organs or tissues where it has an effect. glucagonA hormone produced by the pancreas that broadly opposes the actions of insulin and so increases the blood sugar (glucose) level., which counteracts the action of insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. in the body. It may also result in some weight loss.

Pramlintide injection alongside insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. before meals reduces glucoseA simple sugar that is an important source of energy in the body. levels after eating.[5]

Incretin therapy

Incretins are hormones produced by the gut that increase the secretion of glucoseA simple sugar that is an important source of energy in the body.-dependent insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. during the absorption of nutrients. They also regulate the hormoneA substance produced by a gland in one part of the body and carried by the blood to the organs or tissues where it has an effect. glucagonA hormone produced by the pancreas that broadly opposes the actions of insulin and so increases the blood sugar (glucose) level., which counteracts the effects of insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels..[6,7]

Because incretins are usually broken down quickly in the body, a special long-acting form is used, called exenatide.[8] Given by subcutaneous injection, exenatide stimulates insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. secretion and suppresses the appetite, encouraging weight loss.[2]

Gastrointestinal side-effects include nausea, diarrhoeaWhen bowel evacuation happens more often than usual, or where the faeces are abnormally liquid., abdominal pain and distension.[8,9] Unlike insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels., the dose does not need to be adjusted according to glucoseA simple sugar that is an important source of energy in the body. self-monitoring. Side-effects include nausea.[9]

Drugs that inhibit the breakdown of incretins have also been developed. The first available drug that acts in this way is sitagliptin.[6]

References: 
  1. Scarpello JHB, Howlett HCS. Metformin therapy and clinical uses. Diabetes Vasc Dis Res 2008; 5: 157-67.
  2. Boon NA, Colledge NR and Walker BR. Davidson's Principles and Practice of Medicine Churchill Livingstone Elsevier. 2006; 20th edition.
  3. Lindström J, Louheranta A, Mannelin M et al. The Finnish Diabetes Prevention Study (DPS). Lifestyle intervention and 3-year results on diet and physical activity. Diabetes Care 2003; 26: 3230-6.
  4. Black C, Donnelly P, McIntyre L et al. Meglitinide analogues for type 2 diabetes mellitusDisordered energy metabolism and high levels of glucose in the blood owing to a lack of insulin, or poor response of the body to insulin.. Cochrane Database of Systematic Reviews. 2007; Issue 2.
  5. Hoogwerf BJ, Doshi KB, Diab D. Pramlintide, the synthetic analogue of amylin: physiology, pathophysiology, and effects on glycemic control, body weight, and selected biomarkersA substance that can be measured to help healthcare professionals to assess normal processes, disease processes or a person's response to treatment. of vascular risk. Vascular Health and Risk Management 2008; 4: 355-62.
  6. PJ Boyle, JS Freeman. Application of incretinA type of hormone produced in the gut, which stimulates insulin release. mimetics and dipeptidyl peptidase IV inhibitors in managing type 2 diabetes mellitusDisordered energy metabolism and high levels of glucose in the blood owing to a lack of insulin, or poor response of the body to insulin.. J Am Osteopath Assoc 2007; 107(suppl. 3): S10-6.
  7. Schnabel CA, Wintle M and Kolterman O. Metabolic effects of the incretinA type of hormone produced in the gut, which stimulates insulin release. mimetic exenatide in the treatment of type 2 diabetes. Vascular Health and Risk Management 2006; 2: 69-77.
  8. British National Formulary www.bnf.org Accessed April 20, 2009.
  9. Scheen AJ. Exenatide once weekly in type 2 diabetes. Lancet 2008; 372: 1197-8.