A client with cirrhosis has elevated ammonia. Which medication will the nurse administer to detoxify ammonium and act as an osmotic agent?

• A. Kanamycin
• B. Spironolactone
• C. Cholestyramine
• D. Lactulose

Answer: (D)

Detoxifying ammonium in hepatic encephalopathy relies on trapping ammonia in the gut and increasing its elimination. Lactulose does this by being a nonabsorbable disaccharide that gut bacteria metabolize into organic acids, which lower the colonic pH. The acidic environment converts ammonia (NH3) to ammonium (NH4+), a charged form that cannot readily cross the intestinal mucosa, so it stays in the gut to be excreted. In addition, lactulose acts as an osmotic laxative, drawing water into the stool and speeding intestinal transit, which further reduces ammonia production and absorption in the colon. So lactulose provides both detoxification of ammonium and enhanced elimination via stool, making it the appropriate therapy for cirrhosis with elevated ammonia. Monitor for increased bowel movements and electrolyte imbalance, and adjust the dose to achieve regular soft stools. Kanamycin can reduce gut bacteria but doesn’t provide the osmotic effect; spironolactone addresses fluid issues, and cholestyramine targets bile acids, not ammonia.