What is the recommended dosing for lactulose (lactulose)?

Lactulose Dosing

For acute hepatic encephalopathy, start lactulose at 30-45 mL (20-30 g) every 1-2 hours orally until producing at least 2 soft bowel movements daily, then titrate to 30-45 mL three to four times daily to maintain 2-3 soft stools per day. 1, 2, 3

Initial Dosing for Acute Hepatic Encephalopathy

• Begin with 30-45 mL (20-30 g) every 1-2 hours until achieving at least 2 soft bowel movements daily 1, 2, 3
• This aggressive hourly dosing induces the rapid laxation needed in the initial phase of therapy 3
• Clinical improvement may occur within 24 hours but can take 48 hours or longer 3

Maintenance Dosing

• After achieving initial laxation, reduce to 30-45 mL (20-30 g) three to four times daily 1, 2, 3
• Target 2-3 soft stools per day as the therapeutic endpoint 1, 2, 3
• Continuous long-term therapy is indicated to prevent recurrence of hepatic encephalopathy 3

Rectal Administration (For Severe Cases)

Use rectal lactulose when patients have:

• Severe hepatic encephalopathy (West-Haven grade 3 or 4) 1
• Inability to take oral medications 1
• Risk of aspiration or impending/actual coma 1, 3
• Presence of ileus or abdominal distention 1

Enema preparation and administration:

• Mix 300 mL lactulose with 700 mL water or physiologic saline 1, 2, 3
• Administer via rectal balloon catheter and retain for 30-60 minutes 1, 3
• Repeat every 4-6 hours as needed 3
• If evacuated prematurely, repeat immediately 3
• Transition to oral dosing once coma reverses 3

Pediatric Dosing

• Infants: 2.5-10 mL daily in divided doses 3
• Older children and adolescents: 40-90 mL total daily dose 3
• Reduce dose immediately if diarrhea develops; discontinue if diarrhea persists 3

Critical Monitoring and Dose Adjustments

Monitor for complications of overuse:

• Dehydration and hypernatremia 1, 2
• Severe perianal skin irritation 1, 2
• Paradoxical precipitation of hepatic encephalopathy 1, 2
• Aspiration risk with excessive dosing 1

Check electrolytes regularly to prevent dehydration and electrolyte imbalances 1

Common Pitfalls to Avoid

• Do not exceed the dose that produces more than 3-4 soft stools per day, as this increases risk of complications without additional benefit 4
• Avoid alkaline cleansing enemas (such as soap suds) when using rectal lactulose 3
• Hold oral lactulose in patients with ileus and consider rectal administration or nasogastric tube delivery if appropriate 1
• Do not use magnesium-containing laxatives in patients with renal impairment due to hypermagnesemia risk 1

Efficacy Data

• Lactulose leads to recovery in 70-90% of hepatic encephalopathy patients when properly dosed 1
• The key to success is achieving the target of 2-3 soft stools daily, which requires individualized dose titration 1, 2, 3