Insulin glargine - A review of its therapeutic use as a long-acting agent for the management of type 1 and 2 diabetes mellitus

Insulin glargine is a recombinant human insulin analogue produced by DNA te chnology using a nonpathogenic strain of Escherichia coli. Two modification s of human insulin result in a stable molecule which is soluble in slightly acidic conditions (pH 4.0) and precipitates in the neutral pH of subcutane ous tissue. Because of these properties, absorption of insulin glargine is delayed and the analogue provides a fairly constant, basal insulin supply w ithout peaks in plasma insulin levels for approximately 24 hours, similar t o that achieved by a continuous subcutaneous insulin infusion. Insulin glargine is indicated as a once daily subcutaneous injection to pro vide basal glycaemic control in adults and children aged >6 years with type 1 diabetes mellitus and in adults with type 2 diabetes mellitus. Fasting p lasma glucose and fasting blood glucose levels generally improved to a grea ter extent in patients with type 1 diabetes mellitus receiving insulin glar gine than patients who administered Neutral Protamine Hagedorn (NPH) insuli n. In patients with type 1 or 2 disease, glycosylated haemoglobin levels we re slightly reduced and to a similar extent with insulin glargine and NPH i nsulin. Most clinical trials in patients with type 1 or 2 diabetes mellitus demonstrated a lower incidence of hypoglycaemia, especially nocturnal hypo glycaemia, compared with NPH insulin. One of the most common adverse events with insulin glargine treatment was i njection site pain which, in some studies, occurred more frequently than in patients receiving NPH insulin. In all cases the symptoms were mild and tr eatment discontinuation was not required. Otherwise, the drug is well toler ated and does not appear to be immunogenic. Conclusions: Insulin glargine once a day provides basal control of glycaemi a for approximately 24 hours without inducing peaks in plasma insulin level s in patients with type 1 or 2 diabetes mellitus. In long term, well design ed trials insulin glargine once daily improved glycaemic control at least a s effectively as NPH insulin given once or twice daily. The drug was well t olerated and in most studies the incidence of nocturnal hypoglycaemia was s ignificantly less in patients treated with insulin glargine compared with p atients receiving NPH insulin. Therefore, insulin glargine is likely to be a useful addition to the armamentarium of insulin therapy by establishing b asal glycaemic control with once daily administration and a reduced risk of nocturnal hypoglycaemia.