1.6.4 Osmotic laxatives

Many of these products are cheap to buy and are readily available, along with advice, from pharmacies. Some self-care medicines are available in shops and supermarkets. Please click here for further information and a patient leaflet

Macrogol oral powder, compound

Adult products

  • CosmoCol® oral powder, sachets (un-flavoured, lemon & lime, orange, orange lemon & lime) (£7.37 = one twice daily)
  • Laxido® orange oral powder, sachets (£7.37 = one twice daily)

Paediatric products

  • Cosmocol Paediatric sachets (£5.58 = one twice daily)
  • Laxido Paediatric plain sachets (£5.58 = one twice daily)

Indications and Dose


  1. Prescribe by brand to maintain continuity and avoid confusion
  2. Time to effect: 2-3 days
  3. Each sachet should be dissolved in 125ml water
  4. May cause electrolyte disturbances and some patients find it difficult to drink the prescribed volume. Caution in elderly and fluid restricted patients
  5. Courses should not normally exceed 2 weeks
  6. Paediatric sachets are unlicensed for faecal impaction in children under 5 and for chronic constipation in children under 2 years of age
  • Solution (£2.61 = 500ml)

Indications and dose

  • Constipation in adults
    • Initially 15 mL twice daily, adjusted according to response
  • Constipation in children
    • 1 – 11 months: 2.5 mL twice daily, adjusted according to response.
    • 1 - 4 years: 2.5–10 mL twice daily, adjusted according to response
    • 5 - 17 years: 5–20 mL twice daily, adjusted according to response
  • Hepatic encephalopathy
    • Adult: Adjusted according to response to 30–50 mL 3 times a day, subsequently adjusted to produce 2–3 soft stools per day.


  1. Lactulose takes up to 48 hours to work therefore, should be taken regularly rather than "when required"
  2. Some patients find it unpleasant to take and compliance may be a problem.
  3. Its main clinical benefit is in the management of hepatic encephalopathy.
  4. Fluid needs to be increased whilst taking lactulose
  5. Avoid lactulose in patients with IBS as it may increase gas production and therefore exacerbate symptoms
Phosphate (rectal)
  • Cleen® Ready-to-Use Enema 133ml (£1.95 = per enema)
  • Enema 128ml (short tube £3.98 = per enema; long tube £27.93 = per enema)

Indication and dose

  • Relief of constipation
    • The contents of one single dose enema
  • Perioperative use
    • The contents of one single dose enema


  1. Time to effect: 5 minutes
  2. Useful to remove hard, impacted stools.
  3. Correct administration important to prevent damage to rectal mucosa.
  4. Long tube phosphate enemas are licensed for self-administration. The longer tube is to allow easier self-administration not to allow enemas to be given higher in the rectum.
  5. Licensed for occasional use only.
  6. Use of phosphate enemas are contraindicated in people who have signs of dehydration or significant renal impairment, as there is an increased risk of hypernatraemia, hyperphosphataemia, hypocalcaemia, and hypokalaemia.
  7. Risk of rectal gangrene in people who are systemically unwell with a history of haemorrhoids.
  8. Contra-indications acute gastro-intestinal conditions (including gastro-intestinal obstruction, inflammatory bowel disease, and conditions associated with increased colonic absorption)
  9. Conditions pre-disposing the patient to retention of the enema can make the use of the product hazardous
Sodium citrate
  • Micro-enema 450mg/5ml (£0.43 = 5ml enema)

Indication and dose


  1. Time to effect: 5-15 minutes
  2. Smaller volume than a phosphate enema
  3. Useful to remove hard, impacted stools
  4. Licensed for occasional use only.
  5. Correct administration important to prevent damage to rectal mucosa
  6. Use with caution in the elderly or people at risk of sodium and water retention.

Different brands may have different licensed use and dosage recommendations – refer to SPC of individual brands.


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