Lactulose
General
- Type: osmotic laxative
- Dosage Forms: 10g/15mL solution
- Routes of Administration: oral, NG, rectal
- Common Trade Names: Kristalose
Adult Dosing
Hepatic encephalopathy
- 30-45mg PO TID or QID or (300mL in 700cc H2O retention enema x30min)
- titrate for 2-3 soft stools per day
Constipation
- 15-50mL PO Qday - BID
- max 60mL/day
Pediatric Dosing
Portal systemic encephalopathy
- infants
- 2.5-10ml/day PO divided TID-QID
- titrate for 2-3 soft stools per day
- children
- 40-90ml/day PO divided TID-QID
- titrate for 2-3 soft stools per day
Constipation
- 1ml/kg PO Qday - BID
- max 60mL/day
Special Populations
- Pregnancy Rating: B (no evidence of risk)
- Lactation risk: safety unknown
- Renal Dosing
- Adult: not defined
- Pediatric: not defined
- Hepatic Dosing
- Adult: not defined
- Pediatric: not defined
Contraindications
- Allergy to class/drug
- galactosemia
- caution in DM
- caution if colorectal electrocautery procedures
Adverse Reactions
Serious
- diarrhea, severe (excessive dose)
- electrolyte disorders (excessive dose)
- metabolic acidosis (excessive dose)
Common
- flatulence
- intestinal cramping
- abdominal distention
- nausea/vomiting
Pharmacology
- Half-life: unknown
- Metabolism: colon, <3% systemic absorption
- Excretion: feces (100% unchanged), urine < 3%
Mechanism of Action
- Undigestible disaccharide consumed by large bowel bacteria and broken down to lactic acid
- Acidification of colonic contents attracts ammonia from bloodstream leading to excretion in stool