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Olsalazine sodium

Updated 2 Feb 2023 | Aminosalicylates


Capsules containing olsalazine sodium 250mg

Tablets containing olsalazine sodium 500mg

Drugs List

  • olsalazine 250mg capsules
  • olsalazine 500mg tablets
  • Therapeutic Indications


    Oral treatment of mild active ulcerative colitis and maintenance of remission.



    Acute mild ulcerative colitis
    1g daily in divided doses. Depending upon the patient response, titrate the dose up to a maximum of 3g daily over one week.

    A single dose should not exceed 1g.

    Maintenance of remission of ulcerative colitis
    0.5g twice daily.


    Treatment of acute attack of mild ulcerative colitis
    Children aged 12 to 18 years
    500mg twice daily. Depending on the patient response, titrate the dose up to a maximum of 3g daily over one week.

    A single dose should not exceed 1g.

    Children aged 2 to 12 years (unlicensed)
    500mg twice daily, increased if necessary over 1 week to a maximum of 1g three times daily.

    Maintenance of remission of mild ulcerative colitis
    Children aged 12 to 18 years
    500mg twice daily.

    Children aged 2 to 12 years (unlicensed)
    250mg to 500mg twice daily.

    Patients with Renal Impairment

    The manufacturer states that it is contraindicated in severe renal impairment and should be used with caution in moderate renal impairment.

    The Renal Drug Handbook suggests that in patients with a glomerular filtration rate (GFR) of less than 50ml/min, treatment should be initiated at a low dose and increased according to response.

    Manufacturer recommends to monitor patients with impaired renal function.

    Patients with Hepatic Impairment

    Manufacturer recommends to monitor patients with impaired liver function.


    For oral administration.

    Olsalazine taken on an empty stomach may sometimes lead to loose stools or diarrhoea. By taking the drug at the end of a meal, this may be avoided.

    Capsules can be opened and contents sprinkled on food.


    Severe renal impairment

    Children under 2 years

    Hypersensitivity to salicylates

    Precautions and Warnings

    Olsalazine should be used with caution in patients with moderate renal impairment.

    It is recommended to monitor patients with impaired renal or hepatic function.

    For patients with baseline renal impairment, treatment with olsalazine should only be initiated if the benefits outweigh the risks. Renal function should be monitored before starting olsalazine, every 3 months for the first year, every 6 months for the next 4 years, and annually after 5 years of treatment. Treatment should be discontinued if renal functions deteriorates.

    Patients suffering from severe allergy or asthma should be observed for signs of worsening of these conditions.

    Serious blood dyscrasias have been reported very rarely with olsalazine. Haematological investigations should be performed if the patient develops unexplained bleeding, bruising, purpura, anaemia, fever or sore throat. Treatment should be stopped if there is a suspicion or evidence of a blood dyscrasia.

    Patients should be instructed how to recognise the sings of haematotoxicity and should be advised to contact their physicians immediately if the symptoms develop.

    Children under 18 years - see ' Dosage - Children' section

    Pregnancy - see 'Pregnancy' section

    Breastfeeding - see 'Lactation' section

    Pregnancy and Lactation


    Use with caution in pregnancy.

    Reproductive studies in rats have revealed reduced foetal weights, retarded ossifications, and immaturity of the foetal visceral organs with doses 5 - 20 times the recommended dose of a weight basis.

    There are no adequate or well-controlled studies in pregnant women and at the time of writing no reports of its use have been located.

    In inflammatory bowel disease, symptoms and activity are linked to pregnancy outcomes, active disease being associated with low birth weights, higher rates of spontaneous abortion, prematurity and perinatal complications.

    Although Schaefer concludes that olsalazine may be used in pregnancy if necessary, both Schaefer and Briggs suggest that the 5-aminosalicylic acid derivative of choice is mesalazine due to the greater body of evidence concerning its use.

    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 ( ).


    Olsalazine is excreted into human milk although only a small percentage of an oral dose to the mother is absorbed. Nursing infants of women being treated with olsalazine should be closely observed for changes in stool consistency although there are a very few reports of adverse effects with the 5-aminosalicylic acid derivatives.

    Schaefer suggests that olsalazine may be used during breastfeeding, however the manufacturer recommends its use only if the benefit of the treatment outweighs the risks.

    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

    The ability to drive or operate machinery may be affected by side effects, especially dizziness and blurred vision.


    Advise patients that dizziness and blurred vision have been reported as side effects. If affected, they should not drive or operate machinery.

    Advise patient to report any unexplained bleeding, bruising, purpura, sore throat, fever or malaise that occurs during treatment.

    Side Effects

    Blood dyscrasias
    Aplastic anaemia
    Haemolytic anaemia
    Exacerbation of colitis
    Hypersensitivity reactions
    Acute pancreatitis
    Interstitial lung disease
    Fibrosing alveolitis
    Renal impairment
    Interstitial nephritis
    Nephrotic syndrome
    Skin reactions
    Lupus erythematosus-like syndrome
    Stevens-Johnson syndrome
    Peripheral neuropathy
    Blurred vision
    Angioneurotic oedema
    Serum bilirubin increased
    Elevation of liver enzymes
    Upper abdominal pain


    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

    Store at room temperature in a dry place.

    Further Information

    Last Full Review Date: May 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: Olsalazine Sodium Capsules 250mg. Atnahs Pharma UK Ltd. Revised May 2021.

    Summary of Product Characteristics: Olsalazine Sodium Tablets 500mg. Atnahs Pharma UK Ltd. Revised May 2021.

    The Renal Drug Handbook. Fifth Edition (2019) ed. Ashley, C. and Dunleavy, A. Radcliffe Publishing Ltd, London.

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

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Olsalazine. Last revised: January 04, 2011
    Last accessed: May 23, 2012

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