Lactulose

Lactulose

[10ml 10 cents]

ADMINISTRATION ROUTES:

  • PO, NG

ALTERNATIVE NAMES:

  • Duphalac

ICU INDICATIONS:

  1. constipation
  2. hepatic encephalopathy

PRESENTATION AND ADMINISTRATION:

  • PO:
    Duphalac 10g/15ml
    Store at room temperature

DOSAGE:

  • PO:
    Constipation

    10-20ml 12-24 hourly.
    Hepatic Coma

    Hourly doses of 30-45 ml of lactulose may be used to induce the rapid laxation in the initial phase of the therapy of portal-systemic encephalopathy. When the laxative effect has been achieved, the dose of lactulose may then be reduced to the recommended daily dose of 30-45ml 3-4 times daily. Continuous long-term therapy is indicated to lessen the severity and prevent the recurrence of portal-systemic encephalopathy. The dose for this purpose is the same as the recommended daily dose.

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose as in normal renal function

DOSAGE IN PAEDIATRICS:

  • PO:
    Constipation

    0.5mg/kg 12-24 hourly
    Hepatic coma

    1mg/kg hourly until bowel cleared then 1mg/kg 6-8 hourly

CLINICAL PHARMACOLOGY:

  • Lactulose is a synthetic disaccharide in solution form for oral administration. It is a colonic acidifier that promotes laxation. Lactulose causes a decrease in blood ammonia concentration and reduces the degree of portalsystemic encephalopathy. These actions are considered to be results of the following: Bacterial degradation of lactulose in the colon acidifies the colonic contents. This acidification of colonic contents results in the retention of ammonia in the colon as the ammonium ion. Since the colonic contents are then more acid than the blood, ammonia can be expected to migrate from the blood into the colon to form the ammonium ion. The acid colonic contents convert NH3 to the ammonium ion (NH4)+, trapping it and preventing its absorption. The laxative action of the metabolites of lactulose then expels the trapped ammonium ion from the colon.

CONTRAINDICATIONS:

  1. mechanical bowel obstruction
  2. since lactulose contains galactose, it is contraindicated in patients who require a low galactose diet.

WARNINGS

  • Infants receiving lactulose may develop hyponatremia and dehydration.

PRECAUTIONS

  • General:
    See WARNINGS and CONTRAINDICATIONS
  • Laboratory Tests:
    No tests in addition to routine ICU tests are required
  • Drug/Laboratory Test Interactions:
    None known

IMPORTANT DRUG INTERACTIONS FOR THE 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

Critical Care Drug Manual

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