They are powerful and increase the secretion of insulin. At one stage they were the only oral drugs available. They suffer from some major adverse effects; one being that they can cause hypoglycaemia when taken in over-dosage. Another is that they only have a limited life cycle, after a long continued use they seem to lose their blood glucose lowering effects. They can cause weight gain. This group are subject to sulphonyl group allergies and they are no longer the first line of treatment.
The second major oral drug used for treatment for diabetes was originally developed from a herb, french lilac. It was experimented with for many different purposes and was largely forgotten. It was later rediscovered as a very powerful anti-diabetic drug. Metformin not only helps reduce Blood glucose levels but also increases the body’s tissues sensitivity to natural insulin. Its major draw back is that it is not recommended where there is kidney failure, lung disease and liver disease. Some patients can suffer some gastrointestinal upsets, although this side effect can be largely overcome by increasing the dosage gradually. Thus, because of its effectiveness, Metformin is largely the “Gold Standard” for first line of drug treatment for Diabetes type II.
Another drug group used for treating Diabetes are Glinides. They work similar to the Sulphonylareas but on different sites, and can be prescribed to those allergic to the Sulphonyl drugs. They are a little less potent.
Acarbose is a drug that slows the breakdown of polysaccharides and hence reduces the after eating spike of high blood glucose. It has a useful effect, but it is limited by it causing much bloating and gastrointestinal upset.
One class of drugs, Gliptins, work by protecting an enzyme GLP-1. GLP-1 reduces glucose release and simulates food related insulin release. They do not cause weight gain and have few drug interactions. Unfortunately, their effects are limited and this class of drug which includes Sitagliptin are mainly prescribed as an adjunct with Metformin.
An other newer drug group, SGLT-2 , block the body's re-uptake of sugar from the kidneys. This causes the body to deliberately lose glucose in the urine. They cause a moderate reduction of blood sugar and mild weight loss. The increased loss of glucose can increase the incidence of urinary tract infections.
Your Physician has a range of drugs to work with to lower your Blood Glucose and they are usually selected by taking into account: your health factors, your body's response, drug toxicity, other medication that may interact, and importantly, your compliance to your medication and diet schedule.
There are newer glycemic control drugs currently being developed , some will show promise and others disappointment.