ADMINISTRATION ROUTES:
PO, NG
ALTERNATIVE NAMES:
Duphalac
ICU INDICATIONS:
- Constipation
- Hepatic encephalopathy
PRESENTATION AND ADMINISTRATION:
PO/NG:
Duphalac 10g/15 mL
Store at room temperature
DOSAGE:
PO:
Constipation
10-20 mL BD or OD
Hepatic Coma
Initally 30-45 mL hourly until bowel cleared
Reduce to 30-45 mL QID or TDS once achieved
Coma from portal-systemic encephalopathy should be treated aggressively with frequent dosing, reducing when constant watery diarrhoea is produced. Continuous long-term therapy is indicated to lessen severity and prevent recurrence of portal-systemic encephalopathy. The dose for this purpose is the same as the reduced dose above, with an aim of 2-3 loose soft bowel motions per day
DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:
Dose as in normal renal function
DOSAGE IN PAEDIATRICS:
PO:
Constipation
0.5 mg/kg BD or OD
Hepatic coma
1 mg/kg hourly until bowel cleared
Reduce to 1 mg/kg QID or TDS
CLINICAL PHARMACOLOGY:
Lactulose is a synthetic disaccharide in solution form for enteral administration. It is a colonic acidifier that promotes laxation. Lactulose causes a decrease in blood ammonia concentration and reduces the degree of portal systemic encephalopathy. These actions are due to the following process:
- Bacterial degradation of lactulose in the colon acidifies colonic contents
- Acidification of colonic contents results in the retention of ammonia in the colon as the ammonium ion
- Colonic contents is now more acidic than blood so ammonia migrates from blood into the colon
- The acidic colonic contents converts ammonia (NH3) to ammonium ion (NH4+), trapping it and preventing its absorption
- The laxative action of the metabolites of lactulose expels the trapped ammonium ion from the colon
CONTRAINDICATIONS:
- Mechanical bowel obstruction
- Since lactulose contains galactose, it is contraindicated in patients who require a low galactose diet
WARNINGS:
Infants receiving lactulose may develop hyponatraemia and dehydration
PRECAUTIONS:
General:
See WARNINGS and CONTRAINDICATIONS
Laboratory Tests:
No tests in addition to routine ICU tests are required but electrolytes should be monitored closely, particularly in children
Drug/Laboratory Test Interactions:
None known
IMPORTANT DRUG INTERACTIONS IN ICU:
Other laxatives should not be used, especially during the initial phase of therapy for portal-systemic encephalopathy, because the loose stools resulting from their use may falsely suggest that adequate lactulose dosage has been achieved.
ADVERSE REACTIONS:
Gastrointestinal:
Diarrhoea, nausea and vomiting, gaseous distention with flatulence or belching, abdominal discomfort
Metabolic:
Dehydration, hypokalaemia, hypernatraemia