Osmotic Laxative Pregnancy: Can be used during pregnancy - no effects are anticipated since systemic exposure is negligible (limited data, fewer than 300 pregnancy outcomes; animal studies show no reproductive toxicity). Can be used during breast-feeding - no effects on the breast-fed infant are anticipated as systemic exposure is negligible.

Macrogol (Polyethylene Glycol)

Brand names: Movicol, Laxido, CosmoCol

Macrogol (polyethylene glycol) is an osmotic laxative used for chronic constipation and faecal impaction, and it is also useful for opioid-induced constipation.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 1 to 2 sachets per day (each sachet contains 10 g macrogol), preferably taken as a single dose in the morning.

Route: Oral - each sachet should be dissolved in a glass of water (approximately 125 ml) just before use; the resultant solution is clear and transparent like water

Frequency: Once daily (single morning dose); the daily dose should be adapted according to clinical effect and may range from one sachet every other day up to 2 sachets a day

Max: 2 sachets a day (the SPC states the daily dose may range from one sachet every other day up to 2 sachets a day)

It is recommended to drink 125 ml of liquid (e.g. water) after each dose. The effect becomes apparent within 24 to 48 hours after administration. Treatment should be stopped gradually and resumed if constipation recurs. Treatment of constipation with any medicinal product is only an adjuvant to a healthy lifestyle and diet. PAEDIATRIC (not a per-kg dose): the SPC gives the same regimen - 1 to 2 sachets per day, preferably as a single morning dose - and states that in children treatment should not exceed 3 months due to a lack of clinical data beyond 3 months; one sachet every other day is noted as especially applicable in children. Verify paediatric use against a children's formulary. CAUTION: in case of diarrhoea, caution in patients prone to disturbance of water and/or electrolyte balance (e.g. the elderly, patients with impaired hepatic or renal function, patients taking diuretics) and electrolyte control should be considered. SOURCE SCOPE: UK SPC for 'PegLax 10 g powder for oral solution in sachet' (macrogol 4000), a maintenance constipation product. High-dose faecal-impaction and bowel-preparation macrogol regimens are NOT covered by this label and must be sourced separately. This draft is extracted from the same source bundle as drugId 'macrogol' (identical eMC product) - keep the two in sync.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Severe inflammatory bowel disease (such as ulcerative colitis or Crohn's disease) or toxic megacolon, associated with symptomatic stenosis
Digestive perforation or risk of digestive perforation
Ileus or suspicion of intestinal obstruction
Painful abdominal syndromes of indeterminate cause

Side effects

Common: abdominal pain and/or distension, diarrhoea, nausea
Uncommon: vomiting, urgency to defecate, faecal incontinence
Very rare: hypersensitivity reactions (pruritus, rash, face oedema, Quincke oedema, urticaria, anaphylactic shock)
Not known: electrolyte disorders (hyponatraemia, hypokalaemia) and/or dehydration, especially in elderly patients
Rarely, severe hypersensitivity reactions and bronchospasm due to the presence of sulphur dioxide in this product

Interactions

Absorption of other medicinal products could be transiently reduced during use; the therapeutic effect of medicinal products with a narrow therapeutic index may be particularly affected (e.g. antiepileptics, digoxin and immunosuppressive agents)

Clinical monograph

How it works

The inert polymer binds water osmotically within the bowel lumen, increasing stool volume and softening it to stimulate a bowel movement; it is not significantly absorbed.

Prescribing in practice

Dissolve each dose in water as directed and maintain an adequate fluid intake.
It is generally well tolerated.
Bloating, abdominal cramps and flatulence can occur, particularly with the higher doses used for impaction.

Monitoring

Review bowel response and tolerability; with the high-dose impaction regimens, be alert to fluid and electrolyte balance, especially in frail or cardiorenally impaired patients.

Counselling the patient

Mix each sachet with water before drinking it, and keep up your fluid intake.
Some bloating or mild cramps are common, especially at first.
It may take a day or two to work fully.

Evidence & guidelines

First-line osmotic laxative in NICE guidance on constipation, including for faecal impaction and opioid-induced constipation.

Reference: NICE CG99 (Constipation in Children 2010); NICE CKS Constipation; SPC Movicol; Cochrane Review — laxatives for chronic constipation; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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