I am taking Humalog and Lantus insulins: 40 units of Lantus and 85 to 90 units of Humalog each day. My morning blood sugar is in the 180 to 200 range. I have had several bad bouts of hypoglycemia and am scared that they could occur while I sleep. Is there a maximum amount of insulin I should take? Should I take an additional dose of Humalog at bedtime? Would different brands of insulin be more effective?
Robert Walz, Phoenix

Christy Parkin, MSN, RN, CDE, responds: The most important concern is the hypoglycemia you are experiencing. Pay attention to when and under what circumstances you have low blood glucose. Is this happening before meals, after exercise, or when you miss or delay a meal? I would suggest that you do a couple of blood glucose tests between
2 and 3 a.m. to see what is happening during the night. I'd also suggest that you keep a written log of all episodes of hypo­glycemia, with details regarding the time and what events preceded the low blood glucose. This is important information to share with your doctor or health care provider in case medication adjustments are needed.

It is possible that the ratio of your Lantus and Humalog insulins is out of balance. As a general rule of thumb, the long-acting insulin (Lantus) should be about 50 percent of your total daily insulin, and the mealtime insulin (Humalog) should make up the other 50 percent, and be split among your three meals. Lantus, your long-acting basal insulin, may need to be increased slowly to bring your morning blood glucose down. This may result in your needing less Humalog before meals, which could decrease the frequency of your lows. I do not recommend that you take an additional dose of Humalog at bedtime, as this will actually increase your chances of hypoglycemia during the night.

There is no maximum amount of insulin that one can take. Some people who are very sensitive to insulin may require small doses, and others who are very insulin resistant will require large doses. You need to take whatever amount is needed to keep your blood glucose in the normal range most of the time. There is no need to switch to different brands of insulin. It is more important to adjust the insulin doses to minimize your hypoglycemia and to lower your fasting blood glucose. I urge you to address all of these issues with your doctor before making any changes.