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Updated 2 Feb 2023 | Osmotic laxatives


Oral solution containing lactulose 3.1-3.7g/5ml

Oral solution containing lactulose 10g/15ml

Drugs List

  • lactulose 10g/15ml oral solution sachets sugar-free
  • lactulose 3.4g/5ml solution
  • Therapeutic Indications


    Not all presentations are licensed for all indications and in all age groups

    Treatment of chronic constipation
    Treatment of hepatic encephalopathy (portal systemic encephalopathy)


    Dosage and age ranges may vary depending on the manufacturer.

    Dosage should be adjusted individually and monitored according to clinical response. Reduce dose if diarrhoea occurs.


    Initial: 15ml to 45ml daily.
    Maintenance: 10ml to 30ml daily.

    Hepatic encephalopathy
    Initially 30ml to 50ml three times daily. Adjust dosage to produce 2 or 3 soft stools daily.


    Children aged 14 to 18 years
    15ml to 45ml daily.

    Children aged 5 to 14 years
    10ml to 20ml daily.
    Other sources state that unlicensed doses up to 40ml may be used.

    Children aged 1 to 5 years
    5ml to 10ml daily.
    Other sources state that unlicensed doses up to 20ml may be used.

    Children aged under 1 year
    5ml daily.

    Hepatic encephalopathy (unlicensed)
    Children aged 12 to 17 years: 30ml to 50ml three times daily. Adjust to produce 2 or 3 soft stools daily.


    For oral administration.

    Lactulose may be taken with water or fruit juice and this may help with nausea.


    Intestinal obstruction

    Precautions and Warnings

    Not all presentations are licensed for all indications and all in age groups.

    Lactulose should be used with caution in patients exhibiting lactose intolerance or glucose-galactose malabsorption syndrome.

    Some formulations contain fructose use with caution in hereditary fructose intolerance.

    It may take 48 hours before the effects are obtained due to the mode of action of lactulose.

    Advise patients to consult a physician in case of insufficient therapeutic effect after several days.

    Use with caution in patients with diabetes mellitus when given at high doses (e.g. in hepatic encephalopathy).

    Advise the patient to drink around 6 to 8 glasses of fluids during treatment.

    Chronic use of unadjusted doses and misuse can lead to diarrhoea and disturbance of the electrolyte balance.

    The defaecation reflex may be altered during the treatment with lactulose in children under 6 years.

    Pregnancy and Lactation


    Wide clinical experience, together with data from animal reproduction studies has not revealed any increase in embryotoxic hazard to the foetus, if used in the recommended dosage during pregnancy.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14-17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    No adverse effects have been reported using this product during breastfeeding. The UK Drugs in Lactation Advisory Service classifies lactulose as suitable for use in breastfeeding. The absorption from the gastro-intestinal tract is minimal.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Effects on Ability to Drive and Operate Machinery

    No effects on the ability to drive or operate machinery has been observed.


    Advise patients that the product may take 48 hours before effects are apparent.

    Advise patients, particularly parents or carers of children, that prolonged use may contribute to the development of dental caries and that good dental hygiene should be maintained.

    Advise patients to consult a physician in case of insufficient therapeutic effect after several days.

    Advise patient that it is recommended to drink sufficient amounts of fluids during treatment (6 to 8 glasses).

    Side Effects

    Electrolyte disturbances
    Abdominal pain
    Abdominal cramps
    Abdominal discomfort


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Shelf Life and Storage

    Do not store above 25 degrees C.
    Do not refrigerate or freeze.

    Further Information

    Last Full Review Date: January 2012

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Summary of Product Characteristics: Duphalac. Abbott Healthcare Products Ltd. Revised August 2012.
    Summary of Product Characteristics: Lactugal. Intrapharm Laboratories Ltd. Revised January 2012.
    Summary of Product Characteristics: Lactulose solution. Sandoz Ltd. Revised December 2007.
    Summary of Product Characteristics: Lactulose 10g/15ml oral solution. Intrapharm Laboratories Ltd. Revised October 2011.

    NICE Evidence Services Available at: Last accessed: 22 August 2017

    UK Drugs in Lactation Advisory Service.
    Available at:
    Last accessed: January 12, 2012

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