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Lactulose

Medication osmotic laxative digestive
Aka: Duphalac
Brands seen in Singapore: Duphalac, Lactus, Lactul, Dhactulose
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Constipation · also used for hepatic encephalopathy
When to take
NHS: 15 ml twice a day to start · 2 days to take effect
Take with
With or without food · can be diluted with water or juice
Pros & cons
Pros
  • General sale list in SG — no prescription needed
  • NHS: no known problems mixing it with other medicines
  • Draws water into the bowel to soften stools
Cons
  • NHS: takes at least 2 days to work
  • Diarrhoea, bloating and wind are common
  • Contains lactose and galactose — not for everyone
Sources
  1. NHS medicines A–Z — About lactulose · read 2026-08-27
    what it says
    “Lactulose is a laxative taken to treat constipation. It's also taken to help a condition caused by severe liver disease called hepatic encephalopathy … Lactulose relieves constipation by drawing water into your bowel to make poo softer”
  2. NHS medicines A–Z — About lactulose, Key facts · read 2026-08-27
    what it says
    “The most common side effects are diarrhoea, bloating and wind … Lactulose takes at least 2 days to work … If you find the taste … too sweet, you can dilute it with fruit juice or water”
  3. NHS medicines A–Z — How and when to take lactulose · read 2026-08-27
    what it says
    “Your dose … can go up or down, depending on how well the medicine is working. The usual dose for constipation is: adults – 15ml, taken twice a day as a starting dose … You can take lactulose with or without food”
  4. NHS medicines A–Z — Who can and cannot take lactulose · read 2026-08-27
    what it says
    “Lactulose … tell your doctor or pharmacist if you: … cannot process a sugar called galactose (galactosaemia); have diabetes, as lactulose may affect your blood sugar levels if you need to take high doses for a long time … have irritable bowel syndrome”
  5. NHS medicines A–Z — Taking lactulose with other medicines and herbal supplements · read 2026-08-27
    what it says
    “There are no known problems mixing lactulose with other medicines or herbal remedies … Only take 2 laxatives together on the advice of your doctor or pharmacist, as there's an increased risk of side effects”
  6. HealthHub (MOH Singapore) — Lactulose, medication information leaflet, article last reviewed 12 August 2026 · read 2026-08-27
    what it says
    “This medication is used to treat constipation. It encourages bowel movement by drawing water into the bowel … This includes a history of lactose or milk intolerance … pre-existing / or a history of bowel obstruction … This preparation contains both lactose and galactose”
  7. FDA DailyMed — Lactulose oral solution (10 g/15 mL) prescribing information, PAI Holdings LLC dba PAI Pharma, setid 0f19e4ed-c90a-4330-a7fa-bf911aa98f09, effective 15 Sep 2025 (constipation indication) · read 2026-08-27
    what it says
    “The usual dose is 1 to 2 tablespoonfuls (15 to 30 mL, containing 10 g to 20 g of lactulose) daily. The dose may be increased to 60 mL daily if necessary”
  8. Singapore National Drug Formulary — DUPHALAC SYRUP [SIN02818P] product information (no indication or dosing section published) · read 2026-08-27
    what it says
    “DUPHALAC SYRUP [SIN02818P] … Active Ingredient and Strength LACTULOSE - 67 G/100 ML … Forensic Classification GENERAL SALE LIST … Licence Holder ABBOTT LABORATORIES (SINGAPORE) PRIVATE LIMITED”
  9. HSA — Listing of Registered Therapeutic Products (data.gov.sg dataset d_767279312753558cbf19d48344577084, managed by Health Sciences Authority, last updated 7 Aug 2026), Forensicclassification column · read 2026-08-27
    what it says
    “DUPHALAC SYRUP | SIN02818P | General Sale List — all 4 oral lactulose products in the register are General Sale List (LACTUS SYRUP 66% w/v, LACTUL SOLUTION 670MG/ML, DHACTULOSE SYRUP) (pulled via datastore_search API, 27 Aug 2026)”
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Updated 2026-08-29. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.