Commonly used anti-diabetes drugs (2)

Sulphonylureas are commonly used to treat diabetes. Their discovery dates back to the period of the Second World War by German Scientists. Examples of drugs in this family includes Chlorpropamide marketed as Diabenese, Tolbutamide marketed as Diatol, Glibenclamide/Glyburide marketed as Daonil or Glanil, Gliclazide marketed as Diamicron, Glipizide marketed as Minidiab, and Glimepride which is a newer generation Sulphonylurea marketed as Azulix or Amaryl.

The newer generation Glimepiride has duration of action of about twenty-four hours and once a day use usually suffices in contrast to the other drugs that may be used more than once a day. These drugs ideally should be used about thirty minutes before meals.
They can be used on their own or in combination with other drugs like Metformin.

The main difference among these various drugs is their safety of use in that those of the newer generation are much safer to use in people with diabetes, especially the elderly diabetic. These drugs act by stimulating insulin release from the pancreas; thus they cannot be used in those with Type 1 diabetes whose insulin producing cells in the pancreas have already been destroyed by the body’s immune system.

These drugs are also known to lose their effectiveness in individuals with Type 2 diabetes of long duration; this is due to the fact that as the course of Type 2 diabetes becomes prolonged, the insulin producing cells inside the pancreas become exhausted and therefore cease producing insulin.

The continued use of this group of drugs in such instances is thus akin to flogging a dead horse.
These drugs are majorly excreted by the liver and kidneys and thus should be avoided in persons with diabetes and concomitant liver or kidney disease. All these drugs have a propensity for causing increase in weight while those of the earlier generation especially Chlorpropamide and Glibenclamide can cause severe and prolonged hypoglycaemia (low blood sugar level) which if not quickly recognized and treated can lead to brain damage and death.

Hypoglycaemia is the commonest and most fatal side effect of these drugs.
Chlorpropamide (Diabenese) is no longer recommended for use worldwide because of the severe and prolonged hypoglycaemia it is associated with. Nigeria remains one of the very few countries worldwide where it is still used freely because it is cheap. Safer though relatively costlier alternatives are however very much present in Nigeria.

Other side effects that may follow the use of this group of drugs include nausea, vomiting, diarrhea, headaches, hepatitis (liver injury) and jaundice that may lead to liver failure. They can also cause rash and itching associated with peeling off of the skin in some individuals. Once the rash and itching are noticed, the drug should be immediately stopped and healthcare workers contacted as it may actually proceed to a life threatening skin disorder. Drugs like Glibenclamide and Glipizide have some untoward effects on the heart while drugs like Glimepiride and Gliclazide are not known to have such effects.

Safe use of these drugs includes the fact that adequate quantity of food should be taken after the ingestion of the drugs. Also, once the warning symptoms of low blood sugar level like hunger pangs, tremors of the hands, sweating and excessive beating of the heart are noticed, the individual should quickly ingest sugar or sugar containing drinks to be immediately followed by a solid meal.

These drugs should also be used with great caution in the elderly who may have lost their ability to perceive the warning symptoms of low blood sugar level and are thus likely to develop coma from low blood sugar levels.