The intended effect of lactulose in hepatic encephalopathy is to

• A. Improve mental status
• B. Increase blood pressure
• C. Decrease respiration
• D. Weight loss

Answer: (A)

Lactulose is used in hepatic encephalopathy to lower ammonia levels in the blood, which helps improve mental status. In the colon, it is metabolized by bacteria into acids that acidify the gut contents. This converts ammonia (NH3) to ammonium (NH4+), a form that cannot be easily absorbed and is excreted in stool. With less ammonia reaching the brain, brain function improves, leading to better mental status.

The laxative effect of lactulose also speeds stool passage, which further reduces the time for ammonia production and absorption. This combination is why improving mental status is the intended effect.

Increasing blood pressure, decreasing respiration, or causing weight loss are not the primary goals of lactulose in this context.