Marked deterioration in glycemic control with change in brand of lactulose syrup

Lactulose is a poorly absorbed synthetic disaccharide frequently used in the treatment of portasystemic encephalopathy. Because lactulose syrup contains small amounts of absorbable sugars, it may cause hyperglycemia in diabetic individuals, but is usually well tolerated. We report the case of a patient with diet-controlled diabetes and cirrhosis who experienced a marked deterioration in glycemic control, requiring insulin use, when he began using a different brand of lactulose syrup. The hyperglycemia resolved and insulin was discontinued after use of the original brand of lactulose syrup was resumed.