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Lactose vs. Lactulose

Aug 29, 2011

I recently got a call at my office from a home healthcare nurse who was visiting one of my patients who was suffering from cirrhosis of the liver and experiencing high ammonia levels.

The patient was on basal insulin with mealtime rapid insulin and had been fairly well controlled. Over the past 2 weeks the patient had been experiencing low glucose levels before lunch and bedtime. The patient had gone to the gastroenterologist due to the high ammonia levels and was started on lactulose 30ml with breakfast and dinner.

The home health nurse was calling me to adjust the insulin due to the low readings. I asked the nurse to check the patient’s dosing log to see if anything had changed. Upon reviewing the logs I was able to figure out that the patient was giving extra insulin due to the lactulose dosing. I immediately had the patient return to their old dosing regimen and the low glucose levels disappeared.

Lesson Learned:

Most patients think that lactulose is like lactose and that it is a sugar that will raise glucose readings. However, lactulose is a synthetic sugar that is broken down in the colon into products that pull water out from the body and into the colon. It works by drawing ammonia from the blood into the colon where it is removed from the body. Because it is broken down in the colon it is not absorbed in the intestines and therefore has little if any effect on glucose levels.

Jon Murray, MD
Ruskin, FL

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