My daughter takes Humalog and NPH. How does an endocrinologist calculate the proper insulin doses? Is there a formula based on weight, age, etc.? Is there a book on it?

An old rule of thumb for calculating insulin dose would be to use 0.8 Units per kilogram of body weight for the total daily insulin and to give two thirds of this as NPH and also to give twice as much NPH at breakfast time than at dinner time. Nowadays, it would be more usual to give Lantus at bedtime as basal insulin, calculating the dose against the morning fasting blood sugar. The starting dose is about 40% of the total NPH and needs to be adjusted in the next few days. Likewise, Humalog can be given after the meal and the dose adjusted according to ‘carbs’ consumed and the pre-meal blood sugar. You might also still want to give some NPH at breakfast if you wish to avoid giving insulin at school.

There are formulas for making these calculations, but they really don’t work nearly as well as the individualised approach based upon lots of blood sugar tests.

DOB