Lactulose — Drug Interactions, Alcohol & Pregnancy Guide
Last reviewed: · Source: US FDA drug label database · 247CanITakeWith Editorial Team
- Lactulose is a Osmotic laxative used for Constipation.
About Lactulose
Lactulose is an osmotic laxative that draws water into the bowel. It takes 48-72 hours to work. For hepatic encephalopathy, higher doses are used to reduce ammonia-producing bacteria in the gut.
Also sold as: Duphalac
Lactulose at a glance
Lactulose is classed as osmotic laxative and is used for constipation, hepatic encephalopathy. It can be bought over the counter in the UK, but that does not mean it is safe with everything — check the label and ask a pharmacist if you take other medicines.
Typical adult dosing guidance: 15-30ml twice daily for constipation. Your own label or prescription always takes priority over general figures.
Our records list no major drug interactions for Lactulose at standard doses. Still tell your pharmacist about everything else you take, including supplements.
Before you combine Lactulose with anything new
- Read the patient information leaflet for both products.
- Keep one up-to-date list of every medicine and supplement you take.
- Ask a pharmacist — it is free and takes a couple of minutes.
- Seek urgent medical help if you feel seriously unwell after combining medicines.
More in this category: gastrointestinal
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Frequently Asked Questions
What is Lactulose used for?
Lactulose is a Osmotic laxative used for Constipation, Hepatic encephalopathy.
What is the maximum adult dose of Lactulose?
The maximum adult dose is 15-30ml twice daily for constipation. This is general guidance — always follow the dose on your prescription or product label, and check with a pharmacist if you're unsure.
Is Lactulose available over the counter in the UK?
Yes, Lactulose is available over the counter in the UK.
Does Lactulose have major drug interactions?
Our records list no major drug interactions for Lactulose at standard doses. That does not rule out an individual risk, so still mention it to your pharmacist when you start any new medicine.
What are the brand names for Lactulose?
Lactulose is sold under brand names including Duphalac. The active ingredient is the same, so check labels carefully to avoid doubling up on it.
Do I need a prescription for Lactulose?
Lactulose does not need a prescription in the UK, but a pharmacist can still advise whether it suits you alongside your other medicines.
Not sure if Lactulose is safe with your other medications?
HealthLabs.com lets you check liver enzyme or kidney function levels before combining medications long-term — no GP referral needed.
Check your levels at HealthLabs →Always speak to your pharmacist or GP for personalised medical advice. Affiliate link — we may earn a commission.