Dr. S.M.Sadikot.
Hon. Endocrinologist,
Jaslok Hospital and Research Centre,
Mumbai 400026

When you first go to see your doctor with your diabetes problem, he will most probably ask you to follow a diet and exercise program. Some of you will be controlled with this and your doctor will then ask you to continue with your diet and exercise. He will, of course, keep monitoring your diabetes regularly.

Some of you may not show an adequate response to the diet and exercise, or the initial control may deteriorate so that your doctor will then add some medications. Whilst this may be insulin, in most instances since you have Type 2 diabetes, it will be a tablet.

It is not absolutely necessary that all patients first be given a trial with diet and exercise. Even at first, if your blood glucose levels are very high, you have severe symptoms usually associated with a high blood glucose, or are feeling very weak and have lost a lot of weight, the doctor may start you with a medication along with diet and exercise.

Later, it may be that you are able to get off the tablets, but that will depend on your response to the treatment and what your doctor judges to be good control.

At the same time, it is a fact that most people with Type 2 diabetes will sooner or later need some oral medications, which may even be in combination with insulin injections.

A word of caution here.

Many people feel that now that they are on medications, there is no need for them to diet or exercise. This is absolutely wrong. Diet and exercise will always be central to your management. The tablets and if necessary, insulin injections, are always in addition to the diet and exercise prescribed to you.

Many of you must already be on tablets for your diabetes and some of you may soon need to take tablets for your diabetes. It is important for you to understand how these tablets work to decrease the blood glucose levels, as well as the doses, how the tablets should be taken and other aspects such as their side effects and interactions with any other medication which you may be taking.

Previously, we have already discussed how the body regulates the blood glucose levels to within normal values. Insulin plays a key role in this. When the food that we eat is digested and enters the blood stream, the pancreas secretes insulin which allows the glucose to be taken up by the cells of the body and also by the liver. It also stops the liver from manufacturing "new" glucose and since the secretion of insulin is closely linked to the blood glucose levels, it maintains the se levels within normal limits.

We have also discussed the reasons for the increase in blood glucose levels in Type 2 diabetes.

Very simply, the following factors play a role in the increase in the blood glucose levels seen in diabetes:

a) The secretion of the insulin from the pancreas is less than that which is necessary to control the blood glucose levels.

b) Even the insulin which is secreted by the pancreas is delayed, so that the blood glucose after eating rises and the insulin then is secreted later and not closely linked to the rising blood glucose levels. This often leads to very high post food glucose levels.

c) There is insulin resistance. Whatever insulin is secreted cannot show its action on the other cells as these cells are "resistant" to the actions of insulin. Thus, the cells cannot utilize glucose and the liver continues to manufacture "new" glucose, leading to high blood glucose levels at all times.

It is a combination of these three factors which are mainly responsible for the increase in the blood glucose levels seen in diabetes. In some people one of the factors may be more important and in some others, the other factors. But simply put, it all comes down to an interplay between these three factors.

Once this is understood, then one can easily understand where the tablets that you take for diabetes work.

They may increase the amount of insulin secreted by the pancreas, or decrease the time lag between the rise of glucose in the blood and the insulin secretion from the pancreas. The tablets may also act by reducing the insulin resistance.

So what are the various tablets available for use in diabetes?

Sulfonylureas
First introduced in the U.S. in 1954, sulfonylureas stimulate the beta cells to produce more insulin. They will not work in anyone with Type 1 diabetes nor in anyone whose beta cells can no longer make insulin. This class of drugs helps only those who have some beta cell function and are able to produce sufficient amounts of insulin, which in turn reduces hepatic glucose output and increases peripheral glucose disposal.

The sulfonylureas are often classified as belonging to the first or second generation. The first generation drugs are rarely used and not available in most places.

Some sulfonylureas work all day, so you take them only once. Others are taken twice each day. Your doctor will tell you how many times a day you should be taking yours.

The correct time to take these medications varies. If you take the medication once a day, you will probably take it just before breakfast. If you take it twice each day, you will probably take the first pill before breakfast and the second one just before dinner. Take the medications at the same times each day. Your doctor can tell you when to take your medication, depending on the type of sulfonylurea prescribed.

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Although many text books list a large number of side effects, the main ones are a low blood glucose level, stomach upsets, a metallic taste in the mouth, a skin rash and itching and weight gain which in some cases may be due to fluid retention.

There are many drugs which interact with sulfonylureas either making the body more sensitive to the sulfonylureas or interfering with their action. It is absolutely essential that you tell your doctor all the medications which you are taking. This interaction can also be with some drugs which we commonly use for minor problems and one should preferably clear all such use with your doctor.