When and how to start insulin for diabetes type 2 in primary care?

More type 2 diabetes are using insulin, about twice as many are on insulin along with their oral medications as 10 years ago. Insulin is the most effective drug for lowering blood glucose. Many experts now start it earlier to help patients get to A1c goals sooner and decrease the risk of complications later. BUT as a pharmacist, when and how to use it?!

          STARTING insulin ― Type 2 diabetes usually go through many oral drugs before "resorting" to insulin. Instead, suggest adding insulin SECOND-line after metformin if A1c is above 8.5%, or estimated average glucose is above 197 mg/dL. Or recommend adding insulin THIRD-line instead of adding a third oral drug. The insulin combination usually works better. Start with a longer-acting, "basal" insulin (NPH, Lantus, Levemir) once daily especially if fasting glucose is high. Suggest a premixed combination such as 70/30 or 75/25 before breakfast and dinner for high glucose after meals. But keep in mind that doses are harder to adjust with fixed combinations. Help new users get comfortable with injecting, monitoring, etc.

COMBINING insulin ― Continue metformin (Glucophage) with insulin, it has insulin-sparing effects and might reduce weight gain. Suggest stopping sulfonylureas when insulin is added. At this point, there's usually not much added benefit. Be careful when insulin and glitazones are used together. The combination can lead to edema and increase the risk of heart failure. Remember, ADA no longer recommends Avandia (rosiglitazone). Discourage using it due to its potential cardiac risk. Watch for errors with insulin Rxs, especially eRxs. "U-100" has been mistakenly entered as (100 units) and "1 unit" as (1 mL).

REFERENCES

• Hirsch, I.B., Bergenstal, R.M., Parkin, C.G., Wright, E. and Buse, J.B. (2005). A Real-World Approach to Insulin Therapy in Primary Care Practice. Clinical Diabetes, 23(2), pp.78–86. Available at: https://clinical.diabetesjournals.org/content/23/2/78

  Nathan, D.M., Buse, J.B., Davidson, M.B., Heine, R.J., Holman, R.R., Sherwin, R. and Zinman, B. (2006). Management of Hyperglycemia in Type 2 Diabetes: A Consensus Algorithm for the Initiation and Adjustment of Therapy: A consensus statement from the American Diabetes Association and the European Association for the Study of Diabetes. Diabetes Care, 29(8), pp.1963–1972. Available at: https://pubmed.ncbi.nlm.nih.gov/16873813