From Hendersonville, North Carolina, USA:
My 8 year old son was recently switched to pork NPH and Humalog. It appears that the NPH acts much longer in my son than the "typical" times. When he takes a shot at 6 P.M., it appears that the NPH is still going strong well into the morning resulting in higher breakfast readings and then a huge drop mid-morning to lunch time. I have experimented by moving his NPH up a couple of hours which helps somewhat with the lunch time lows, but then he has to take an extra injection. Do you have any suggestions?
P.S. To determine which insulin was working at what times, I did a "fasting" test first thing in the morning for several hours and his blood sugars continued to drop all morning long.
Every patient is different, so I can't give you an exact answer, but I will tell you that it is my experience as you report that insulin often lasts much longer than you read in the books. Usually there is considerable overlapping of the actions of insulin. In addition, the larger the dose, the longer it lasts. I'm not sure your "fasting" test proved much as it is very common that the evening insulin lasts well into the morning (and overlaps the morning fast acting insulin). I think the more important issue is to try and figure out when you change an individual insulin, when do the blood sugars really change as opposed to when you think they should change. To determine this you should change only one insulin at a time, try to keep the food and exercise the same, and then see when during the day the blood sugars change.
Of course, the main thing is to figure out how to get the blood sugars lower in your child. I have often seen that people will continue to try and increase the evening dose of NPH to try and lower the blood sugar before breakfast, without realizing that the blood sugar is going lower before lunch or even in the afternoon, but not changing before breakfast when it is supposed to change. A clue to this is that the evening insulin is disproportionately high compared to morning dose. Although there are no hard and fast rules, on an average, if someone is taking a combination of NPH and fast acting insulin twice daily, the total morning dose is usually approximately twice the total evening dose. Sometimes, increasing the morning NPH and decreasing the evening NPH helps. Another possibility to consider would be substituting some Regular for part of the evening Humalog or NPH dose. If the NPH lasts longer than average, Regular may also last longer than average, and giving some before supper may actually improve the fasting blood sugar (make sure to check the blood sugar at 3 A.M. to make sure it isn't going low).
Other possibilities to consider are more intensive insulin regimens of intermediate or long acting insulin twice daily with fast acting insulin(s) before each meal, and sometimes adding a very small dose of intermediate insulin before dinner helps lower the fasting blood sugar. Of course, you shouldn't make any changes without consulting with your child's own physician.
Original posting 26 Mar 1999
Posted to Insulin
Last Updated: Tuesday April 06, 2010 15:09:01
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