Glargine and Lispro

Insulin glargine (Lantus; Aventis, Parsippany, NJ) is a recently available basal insulin analog that appears to have a more consistent activity profile than comparable long-acting insulin products (1). It is typically administered as a single injection before bedtime. Due to minor modification of the amino acid sequence in both the A- and B-chains of the insulin molecule, glargine is soluble only in an acidic pH (2). When injected, glargine precipitates in the neutral pH of subcutaneous tissues, prolonging its systemic absorption (2). Clinical trials have demonstrated that compared with NPH insulin, glargine improves fasting glucose in patients with type 1 diabetes (3) and results in less nocturnal hypoglycemia in patients with both type 1 (4) and type 2 (5) diabetes. It may be particularly useful in individuals who demonstrate labile blood glucose control with conventional insulin formulations. One immediately obvious difference between glargine and other long- (or intermediate-) acting insulins is that the product is a clear solution, similar to short-acting products, not a semi-opaque suspension. To avoid confusion …