
April 24, 2005
Blood Tests and Insulin Injections, Insulin
Question from Sault Sainte Marie, Ontario, Canada:
Would you be able to give me the formula for figuring out how much NPH/Humalog is required if going from pumping Humalog back to shots? I can’t seem to find the formula that the nurse who pump trained us gave me and I would like to have it on-hand, in case my son has a pump failure. If he did have to go back to shots, he would be taking the NPH twice a day (morning and evening) with Humalog at breakfast, lunch, if needed, and at supper. If there is another way to use the NPH, rather than twice a day, that information would be appreciated too.
I am in somewhat of a predicament because we are no longer able to go to the pediatric endocrinologist we were going to as we live in northern Ontario and are unable to get down there four times a year due to weather conditions at times, and transportation/accommodation costs. The pediatric endocrinologist is eight hours away from us.
My son currently has a pediatrician who, admittedly, isn’t really all that familiar with type 1, but is very supportive. There are only six pediatricians here, no pediatric endocrinologists, and we are on pediatrician three. I am very comfortable with the knowledge and experience I have in dealing/managing my son’s diabetes, so it doesn’t present a real problem at this point but, I feel uneasy not knowing the formula in case of pump failure. Also, Lantus isn’t an option for us because it has only been approved for people 17 and older in Canada.
My son is 13 1/2 and has been pumping since September 2002. He was diagnosed in September 2000.
Any assistance you can provide would be appreciated.
Answer:
Although you may not be able to see your previous pediatric endocrinologist, I do not think you should feel abandoned or estranged from them. You should be able to call them and ask for their particular advice.
That said, in very GENERAL terms, you have several options that immediately come to my mind. Too bad you don’t have access to Lantus. Do you have access to Ultralente insulin? It also can be used as a “basal” insulin, although it is not as peakless as Lantus.
Option 1: Just switch back to your last routine dosage of NPH and Humalog. It might be a little awkward and you may not have the smoothest of transitions, but it is a tried and true way of giving insulin and can avoid Diabetic Ketoacidosis (DKA).
Option 2: Add up your child’s daily total hourly BASAL dose rates. DIVIDE that by about 0.8. That new number may approximate the amount of background insulin, the way that NPH would work, on a daily basis. So, for example, let’s say that from Midnight to 8 a.m., he receives 0.2 units per hour; then from 8 a.m. until 3 p.m., he receives 0.17 units per hour; then from 3 p.m. until midnight, he receives 1.1 units per hour. His total daily basal dose is 12.7 units. 12.7 divided by 0.8 = 15.9 units. I’d round this to 16 which would be the ESTIMATED daily NPH requirement. Commonly, two-thirds of the dose is needed in morning and the remaining one-third in the evening. So, using this example, you’d give 11 units in the morning and five units in the evening.
Please make no major insulin adjustments without input from your own diabetes team. I would be surprised if they did not want to give you a “back-up” plan if you had pump issues.
DS
[Editor’s comment: You should be able to dose the Humalog the same way you are using now as boluses with the pump. If you were to use Ultralente instead on NPH, you would need to consult your pediatric endocrinologist for his/her input on amounts and time(s) of day for the injections.
BH]