Lactulose Sandoz (Lactulose)

• Lactulose is an osmotic laxative that acts on the gastrointestinal tract to treat two main conditions.
• Constipation: relieves constipation by increasing water content in the stool and stimulating bowel movements.
• Hepatic encephalopathy: lowers blood ammonia levels, helping to improve mental status in patients with liver‑related encephalopathy.

• Lactulose is a synthetic disaccharide that is not absorbed in the small intestine. In the colon it is metabolised by bacteria, creating acidic metabolites that increase osmotic pressure, draw water into the lumen, and lower colonic pH. The resulting softening of stool promotes evacuation, while the acidified environment reduces ammonia absorption, benefiting patients with hepatic encephalopathy.

Lactulose may cause a range of adverse reactions, most of which are mild and transient.

Common Side Effects

• Abdominal bloating or distension
• Flatulence or gas
• Diarrhoea or loose stools
• Nausea or mild stomach upset
• Abdominal cramps or discomfort
• Increased thirst

Serious or Rare Side Effects

• Severe electrolyte imbalance (e.g., low potassium)
• Marked dehydration
• Allergic reactions such as rash, itching, or swelling
• Severe abdominal pain or colitis
• Rare cases of hepatic decompensation in vulnerable patients

When using Lactulose, certain safety measures should be observed to minimise risk.

• Dose adjustment: tailor the dose in patients with renal impairment or severe liver disease.
• Electrolyte monitoring: check serum electrolytes regularly, especially potassium.
• Diabetes caution: consider the sugar content in patients with uncontrolled diabetes.
• Intestinal obstruction: avoid use in patients with known bowel blockage.
• Medical supervision: ensure treatment of hepatic encephalopathy is overseen by a qualified clinician.
• Store at ambient temperature: keep in the original container, protect from moisture and direct sunlight.

Lactulose can interact with other medicines, affecting efficacy or safety.

Major Interactions (Avoid)

• Concurrent use of other osmotic laxatives (e.g., magnesium hydroxide) – may cause severe diarrhoea and electrolyte loss.
• Loop or thiazide diuretics – increased risk of dehydration and electrolyte disturbances.
• Antacids containing magnesium – can amplify the osmotic effect and lead to gastrointestinal upset.

Moderate Interactions (Monitor Closely)

• Antibiotics (e.g., rifaximin) – may alter gut flora and affect lactulose metabolism.
• Metformin – combined gastrointestinal side effects may be more pronounced.
• Iron supplements – lactulose may reduce iron absorption, requiring monitoring of iron status.