Why do people with diabetes type 2 need oral medication instead of insulin?
Without getting too much into detail i will give a very short and simple description of type 1 and type 2 diabetes.
Type 1 Diabetes:
Type 1 Diabetes is a disorder in which the body does not produce insulin (a hormone that aids in moving sugar from the blood to the cells). This type of diabetes can be due autoimmune disorder in which the body does not recognize an organ as its own and attacks it. In type 1 diabetes this organ is the pancreas where insulin is made. This type of diabetes is usually diagnosed in relatively young people and is also known as Insulin dependant diabetes.
Type 2 Diabetes:
In type 2 Diabetes the pancreas still produces insulin but it is less efficient at moving sugar out of the bloodstream and into the skeletal muscle. It can move some but is on a go slow compaired to people with normal insulin efficiency. This results in high levels of sugar in the blood. Type 2 Diabetes used to be thought of as the adult onset type of diabetes. However, an alarming rate of children are now being diagnosed with Type 2 Diabetes.
Initially people with Type 2 Diabetes do not need to be treated with insulin injections so how are they treated?
Type 2 diabetesis a progressive illness and if it is not controlled in the early stage, insulin may be the best choice to control the rising amounts of sugar in the blood.
However, in the early stages it is not necessary in most cases.
There are standards and guidelines to follow which start with Diet, exercise, weight loss, and in many cases some form of oral medication which helps the blood sugar to be removed from the bloodstream and to enter cells where it can be used as energy. When the sugar levels in the blood are constantly high the patient is at risk for other complications which can be life threatening if not controlled. This type of diabetes is very sadly associated with physical inactivity and obesity.On the up side this can be turned around and the related complications can be in some cases avoided.
Oral medications in type 2 diabetes are called Oral Hypoglycaemic Agents ( OHA). There are various types of OHA that can be taken to reduce the blood glucose but their mechanisms of working are different.
Treatment does follow a guideline and therefore the first OHA prescribed is often Sulphonylurea ( SU ) this medication stimulates insulin secretion from the beta cells in the pancreas. This helps to eliminate the resistance of liver and muscle cells and makes them more effective to insulin. In addition they also reduce the release of glucose from the liver which in turn reduces the amount of glucose in the bloodstream.
Su's are known to increase weight and should be combined with a lifestyle change and exercise in obese patients.
The next group of OAH normally prescribed is Metformin. It works by increasing the insulin sensitivity and peripheral uptake of glucose by the liver and muscle cells. Metformin also impairs glucose absorption by the intestine and inhibits glucose production by the liver.
Metformin does not increase weight and is often the drug of choice for overweight patients. It will also be chosen when SU is unable to control the glucose sufficiently. However, metdormin does have some unpleasant side effects for some giving gastrointestinal discomfort, therefore SU is still used more often than metformin.
The next group on the recommendation list is a group called Thiazolidinediones ( TZD )
When metformin or SU's no longer give the desired blood sugar lowering effect a new type of drug is introduced in combination with one of the others.
These drugs act by enhancing the action of insulin on liver and muscle cells to reduce glucose levels in the blood.
The TZD is used when there is a severe reduction in the sensitivity of the cells to respond to insulin.
Pioglitazone one of these drugs has been scientifically proven to have a long time effect in reducing the HBA1c levels and maintaining this effect for up to 3 years and over when taken regularily.
Pioglitazone was tested in over 5000 patients for safety and tolerability . In the proActive study it was shown that patients who had already suffered from an earlier stroke reduced the risk of having another stroke by as much as 47%.
It was also shown in other comparison studies that pioglitazone is the only TZD that reduces the amount of bad cholesterol in the blood reducing risk of associated problems.
Pioglitazone is also the only TZD on guidelines which can be combined with insulin.
Pioglitazone is also prescribed in combination form together with Metformin if so required.
ALL TZD's like all medications have their down sides and this group is contraindicated in patients with heart failure. This is due to the fact that some patients can experience weight gain and fluid retention when taking this medication.
It has also been seen that some eldery women after menopause were seen to have a higher risk for breaking their arms when falling. The same risk was not applied to other breaks like spinal fractures.
New medications are coming onto the market and their effect over time has still to be established through good, reliable controlled studies.
Insulin Resistance and B cell function