In this series of articles about Diabetes, I have tried to simplify the subject as much as possible - and I must admit that what I have written is not the whole truth as might be presented in a textbook for medical students. Diabetes, we now know, is a complex disease - and the pathology of Diabetes extends far beyond the basic problems of inadequate insulin production and insulin ineffectiveness.
What I have tried to do in these articles, using the mnemonic DIABETICS, is to present the truth about Diabetes management in a very practical, plausible and easy to understand manner.
Medicines for Diabetes
The medical treatment of Diabetes in years gone by was relatively straightforward because tablets of the Biguanide group (like Metformin) and the Sulphonylurea group (like Glibenclamide and Gliclazide) plus injections of Insulin were the only choices we had in our therapeeutic armamentarium.
During the past fifteen years or so, novel medications have improved control of high blood sugar in diabetics but these drugs have complicated the picture by increasing the costs of treatment and the range of possible adverse effects of these medications. Consequently it is now not so easy to make a decision as to which particular drug - or combination of drugs - will suit a particular patient at a particular stage in their disease.
National Health and Medical Research Council (NHMRC) Guidelines
Currently, the guidelines advocated by Australia's NHMRC for blood glucose control recommend diet, weight control and physical exercise as the first step, with oral Metformin added when needed followed as necessary by one of the sulphonylurea medications. When and if these become inadequate to control blood glucose levels, the third line agents recommended are Acarbose, Thiazolidinediones, Incretin-based medications and Insulin.
Remembering that in DIABETICS the letters D for Dietary discipline and E for Exercise come BEFORE T for tablets and I for Injections, the first step in taking control of your diabetes once the diagnosis is made is to modify what and when you eat , and increase the amount of physical activity you undertake every day.
If these two measures prove inadequate, most doctors would start you on a small dose of a tablet called Metformin (sold under various trade names like Diabex, Diaformin, Glucophage, etc). Usually one starts with a single 500 mg tablet once or twice a day, and this dose can be increased up to a maximum total daily dose of 2000 grams (divided between breakfast, lunch and dinner times).
Measuring blood glucose levels and the HbA1C level (which indicates what the average blood sugar level was like over the preceding three months) allows the doctor to modify the dosage of metformin in order to achieve optimum blood sugar control. If using the maximum dose permissible of metformin proves ineffective, the usual practice today would be to add a tablet from the suplhonyl urea group. There are several of these available (some common trade names are Daonil, Diamicron, Amaryl, etc) that vary in their duration of action and the rapidity with which they take effect. So, your doctor will select the one that is most appropriate for you.
Third Line Agents
When Diet, weight loss, exercise and therapy with metfromin and sulphonyl urea tablets fails to achieve sufficient control of blood glucose levels, what options are commonly used?
Pioglitazone (sold under the brand name Actos) can be tried, but is associated with weight gain, swelling of the ankles and worsening of cardiac failure. Latterly there has also been a suggestion that long term use is asscociated with an increased risk of bladder cancer. Acarbose is another tablet worth worth trying, although its possible side effects such as flatulence and diarrhoea can prove a social disadvantage.
Incretin-based Tablets
Among the latest medications available for the treatment of Diabetes are those known as DPP-4 Inhibitors - the tablets currently available being Saxagliptin (Onglyza), Sitagliptin (Januvia) and Vildagliptin (Galvus). Basically, these tablets increase the amount of GLP-1, a hormone belonging to the Incretin group.
The Incretins enhance the production of insulin in response to dietary glucose but are realatively inactive when there is no glucose entering the blood from the intestine. Consequently, they are associated with a low risk of Hypoglycaemia (blood sugare levels falling too low). The only limitation of the use of these Incretin-based therapies is the lack of long term data as they are relatively new medications
Next: The Importance of Injections
Sanjiva Wijesinha - Dr. Sanjiva Wijesinha, Associate Professor at Monash University medical school, writes on health, travel and medical topics.
