Lactulose, either as crystals or liquid syrup, is a frequently prescribed osmotic laxative agent in patients with diabetes mellitus (DM). During the manufacturing process, carbohydrate impurities can arise which could increase blood glucose levels with a possible impact on glycemic control. This important issue has now been addressed for the first time in individuals with type 2 DM. A recent RCT confirmed that there is no need to consider carbohydrate impurities in oral lactulose products administered at the recommended doses of 20 g/day and 30 g/day for blood glucose management.
The clinical efficacy of lactulose in treating constipation in adults has been established during the last 5 decades. Lactulose compares well in terms of improved stool consistency and frequency as compared to stimulant and/or fibre-based laxatives while being equally well tolerated. Laxative properties of lactulose appear to be somewhat weaker compared to polyethylene glycol, yet, evidence indicates that it may be associated with a lower risk of diarrhea. This advantage can be explained by the prebiotic properties of lactulose leading to a beneficial modulation of the gut microbiome. It should therefore be generally acknowledged that, due to its proven prebiotic effects, the benefits of lactulose in constipated individuals go well beyond a simple osmotic laxative effect.
Lactulose has been safely used for more than 60 years in the treatment of constipation. Gastrointestinal side effects are generally mild and often transient. At doses in the range of 10-30 g/day, as indicated for the treatment of constipation in adults, the associated risk of diarrhea is rather low. Lactulose was well tolerated in individuals with type 2 DM, and no unexpected safety issues were identified. Consequently, lactulose preparations represent a safe and effective strategy to alleviate symptoms of constipation, also in individuals with impaired glucose tolerance or diabetes.
Lactulose, Constipation, Blood glucose, Type 2 diabetes mellitus, Laxative, Sugar substitute, Prebiotic