My two-year old grandson has just been diagnosed with Type 1 diabetes. His doctor has set up an insulin regimen, and my daughter keeps a reasonable diet. Nevertheless his glucose levels are often above 300 mg/dl pre-insulin injection. How long does it take for insulin levels/responses to settle down in an acceptable range?

In answer to your question, the time that an insulin dose will lower blood sugar depends on the type of insulin given. Most people need a combination of insulin, if not at first than eventually. This combination typically will include rapid-acting insulin to cover foods eaten. This type of insulin begins working in 10 minutes or so, has it strongest action 1-2 hours after injection and wears out 3-4 hours after injection. Combination therapy will also include a longer acting background insulin, of which we have some options. Depending on the type your grandson takes, this longer acting insulin could last 6-24 hours or more (see Types and Duration of Action of Insulins). Managing type 1 diabetes is a balancing act and rather challenging for kids but I think you are right to be concerned about levels of blood sugars that are repeatedly in the 300 range. We do not have perfect tools, so “perfect control” is not possible. Good control is. If your grandson is in the 300 range often, it would merit discussion with the diabetes team about possible adjustments in insulin dosage and/or type.

KS