Lactulosum (Lactulose, Liquid)

Lactulose is used as an osmotic laxative and ammonia‑lowering agent in several clinical situations.

• Constipation: softens stools and increases bowel frequency, facilitating easier passage.
• Hepatic encephalopathy: lowers intestinal ammonia production, helping to improve mental status in patients with liver disease.
• Prevention of hepatic encephalopathy recurrence: maintains low ammonia levels to reduce the risk of future episodes.

• After oral administration, lactulose reaches the colon where resident bacteria hydrolyze it to short‑chain fatty acids such as acetate and propionate. The resulting acidification lowers colonic pH, converting ammonia (NH₃) to ammonium (NH₄⁺), which is trapped in the lumen. The osmotic effect of the unabsorbed sugars draws water into the bowel, increasing stool water content significantly and promoting evacuation effectively.

Lactulose may cause a range of adverse reactions, most of which are related to its laxative action and colonic fermentation.

Common Side Effects

• Abdominal bloating: feeling of fullness or swelling in the abdomen.
• Flatulence: increased intestinal gas production.
• Diarrhea: loose, watery stools occurring more frequently.
• Abdominal cramps: intermittent painful contractions of the gut.

Serious or Rare Side Effects

• Electrolyte imbalance: disturbances such as low potassium due to excessive fluid loss.
• Severe dehydration: marked loss of body water requiring medical attention.
• Allergic reaction: rash, itching, or swelling indicating hypersensitivity.
• Hypernatremia: elevated blood sodium levels in rare cases.

When prescribing lactulose, clinicians should consider several safety measures to minimize risks and ensure appropriate use.

• Renal function assessment: evaluate kidney status, especially in patients with pre‑existing impairment.
• Electrolyte monitoring: check serum potassium and sodium during prolonged therapy.
• Diabetes caution: monitor blood glucose as lactulose may affect glycemic control.
• Pediatric use: adjust dosing carefully and observe for dehydration in children.
• Concomitant laxative use: avoid combining with other strong laxatives to prevent excessive fluid loss.
• Store at ambient temperature: keep below 25 °C in the original container, protected from moisture and direct sunlight.

Lactulose can interact with other medicines, influencing its efficacy or increasing the risk of adverse effects.

Major Interactions (Avoid)

• Antacids containing magnesium: may enhance the osmotic effect and cause severe diarrhea.
• Broad‑spectrum antibiotics: can alter colonic flora, reducing lactulose conversion and effectiveness.
• Diuretics: increase risk of electrolyte disturbances when combined with lactulose‑induced fluid loss.

Moderate Interactions (Monitor Closely)

• Metformin: both agents may affect gastrointestinal tolerance; monitor for increased GI upset.
• Warfarin: occasional reports of altered INR; check coagulation parameters regularly.
• Oral hypoglycemics: lactulose may potentiate hypoglycaemia; observe blood glucose levels.