Are Insulin Sensitizers Useful Additions to Insulin Therapy?

Patients with type 2 diabetes are often overweight and less insulin sensitive, making high doses of insulin necessary to control glucose levels. Because the weight gain associated with insulin therapy can impede therapy progress through worsening insulin sensitivity, insulin sensitizing agents have emerged as useful additions to insulin therapy. Metformin acts through suppression of hepatic glucose production, especially hepatic gluconeogenesis, and increased peripheral tissue insulin sensitivity. The addition of metformin to insulin therapy reduces hemoglobin A1c, total daily dose of insulin, and reduces or prevents the weight gain associated with insulin treatment. Thiazolidinediones (TZDs) act through PPARs to regulate gene expression and increase insulin-stimulated glucose uptake in peripheral tissues, hepatic insulin sensitivity, and insulin sensitivity in adipose tissue through suppression of fatty acid production. TZDs are effective additions to insulin therapy. Each agent must be considered carefully when adding to an insulin regimen.