Insulin Glargine: a review 8 years after its introduction

Insulin Glargine was the first long-acting insulin analog produced by recombinant DNA technology, approved for use by the US FDA in April 2000 and by the European Agency for the Evaluation of Medicinal Products in June, 2000. It has become the most widely used insulin in the USA owing to its long duration of action without a pronounced peak. The principal advantage of insulin Glargine over neutral protamine Hagedorn (NPH) insulin is in a lower frequency of hypoglycemic reactions, thus affording improved safety. It is used in both type 1 and type 2 diabetes, usually as a single daily dose. In type 2 patients, it is often the first insulin introduced as a single daily dose. Although insulin Glargine is typically administered as a single nighttime dose, it can be given in the morning or at any other time convenient for the patient. In labile type 1 diabetes, it is often most effective given as two daily injections. In obese, insulin-resistant patients, it may be best to administer insulin Glargine in two separate doses, owing to the high volumes of injected insulin required. Insulin Glargine does not treat postprandial hyperglycemia. It is necessary to supplement with short-acting insulin at mealtimes to control glucose surges after meals. Insulin Glargine is effective in hospitalized and postsurgical patients on account of its lack of pronounced insulin peaks and long duration of action. Although there is considerable use of Glargine in pregnant diabetic women, there is no definitive study to confirm its benefits. Insulin Glargine is thought to coprecipitate supplementary short-acting insulins when co-administered in the same syringe. Therefore, more injections are typically needed in the usual treatment regimen for insulin requiring diabetes. In many cases, constant basal insulin levels may be achieved with multiple overlapping doses of NPH insulin given together with short-acting insulin at mealtimes. Such a therapy may be less costly, but the major advantage of insulin Glargine remains the greater safety of a lower frequency of hypoglycemic reactions.