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Lactulose in hepatic encephalopathy — GPhC CRA MCQ

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ModerateGI TherapeuticsLactulose in hepatic encephalopathyGPhC CRA

A 55-year-old man with compensated liver cirrhosis due to alcohol use attends the pharmacy. He has been prescribed lactulose 15 mL twice daily. He asks what this is for, as he is not constipated. What is the most appropriate explanation?

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Correct answer: A — Lactulose helps reduce the absorption of ammonia from the gut, which can build up in liver disease and cause confusion

In liver cirrhosis, lactulose is used for the prevention and treatment of hepatic encephalopathy. It works by reducing the absorption of ammonia from the gut by acting as an osmotic laxative (promoting excretion) and by acidifying colonic contents (which converts ammonia to ammonium, which is poorly absorbed). The dose is titrated to produce two to three soft stools per day. This is distinct from its use as a simple laxative for constipation.

Reference: BNF; NICE CKS Cirrhosis