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From South Carolina, USA:

My daughter (12 years old) was diagnosed with Type 1 diabetes about 3 weeks ago. We are still trying to regulate her insulin. We need help in understanding how to regulate it. She averages about 131 mg/dl to about 235 during a 24 hour period. We would like to know how to plan when to take insulin injections and when to eat meals and snacks in order to bring it under control. We understand these times must be spread out equally with the insulin. She is taking a mixture of Humalog and NPH: 5H, 15N a.m. and 5H 8N p.m. It would help us if we knew the following:

  1. How long after injection does the Humalog insulin enters the blood?
  2. How long after injection does Humalog start to peak?
  3. How long after injection does Humalog start to drop?
  4. Same questions for NPH?

If we know this information we should be able to more closely regulate her sugar levels.


At three weeks it's early days to expect to have achieved control. For one thing your daughter is probably still making some of the insulin she needs and blood sugars are sometimes more erratic at this time than later on when no more insulin is being produced. In any case at this time you need to be in frequent touch with your diabetes team especially not only about changes in insulin dose; but also about all the many other questions you will have.

Lispro insulin (Humalog® brand) is a semisynthetic human insulin in which two amino acids have changed position to give it as more rapid action. It begins to work in 10 to 15 minutes and has a maximum effect in 30-60 minutes. The total duration of action is 4 hours. The particular advantage of this insulin is that you can give it immediately after a meal and thus adjust the dose for both the pre-meal blood glucose reading and for appetite. The corresponding figures for NPH are 2 to 4 hours, 6 to 8 hours and 12 to 15 hours.


[Editor's comment: More information about insulin, and its duration of action, is available. WWQ]

Original posting 22 Mar 97


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Last Updated: Tuesday April 06, 2010 15:08:54
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