What it is used for
- Constipation
- Keeping stools soft when straining should be avoided
- Hepatic encephalopathy (confusion linked to severe liver disease), under specialist care
How it works
Lactulose is a sugar-like liquid that is not absorbed; it draws water into the bowel to soften stool and encourage a bowel movement. In liver disease, it also helps remove ammonia through the gut.
How it is taken
Comes as an oral liquid (syrup) and sometimes sachets. It is taken by mouth and can take a day or more to work. Take it exactly as your doctor, pharmacist, or the label directs, and keep up fluid intake while using it.
No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.
Common side effects
- Wind (flatulence) and bloating
- Stomach cramps
- Nausea
- Loose stools if too much is taken
Serious effects — get help
- Severe diarrhea leading to dehydration or salt imbalance
- Severe stomach pain or vomiting (could signal a blockage)
- Signs of dehydration (dizziness, very little urine)
If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.
Interactions to watch
- Few significant interactions; tell your clinician about other laxatives
- In liver disease, other medicines affecting the bowel may matter — follow specialist advice
Who should take care
- Tell your clinician if you have diabetes, as it contains sugars
- Avoid if you have a bowel blockage or certain rare sugar intolerances (galactosaemia)
- Discuss pregnancy and breastfeeding with a pharmacist, though it is often considered suitable
- Drink plenty of fluids
- Seek review if constipation persists or you have severe abdominal pain