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Stimulant / Osmotic Rectal Laxative Pregnancy: Compatible — glycerol suppositories are safe throughout pregnancy; first-line rectal option when oral laxatives insufficient.

Glycerol Suppositories

Brand names: Glycerin Suppositories BP

Adult dose

Dose: One 4g suppository inserted rectally. Moisten with water before insertion. Retain for 15–30 minutes to allow softening and stimulation of defecation.
Route: Rectal
Frequency: Once daily as required
Max: One 4g suppository per dose
Mild osmotic action (draws water into rectum) plus mild rectal irritant effect that stimulates defecation reflex. Onset 15–30 minutes. Useful when oral laxatives are inappropriate (post-operative, unable to swallow, anorectal discomfort). Available in 1g (infant), 2g (child), and 4g (adult) strengths — prescribe correct size.

Paediatric dose

Route: Rectal
Frequency: Once daily as required
Max: 2g per dose (children 1–11 years)
BNF for Children: infants (under 1 year): 1g suppository. Children 1–11 years: 2g suppository. Children 12–17 years: 4g (adult suppository). Moisten with water before insertion. Source: BNF for Children 2024.

Dose adjustments

Renal

No dose adjustment required — not systemically absorbed in significant amounts.

Hepatic

No dose adjustment required.

Clinical pearls

  • Three sizes available — always prescribe the correct size: 1g (infants), 2g (children), 4g (adults). Using adult size in infants risks rectal trauma.
  • Moisten before insertion: dip in water for 5 seconds — reduces friction and discomfort on insertion.
  • Safe and gentle: preferred first-line rectal laxative in post-operative patients, elderly with haemorrhoids, or infants with infrequent stools — no systemic effects.
  • Onset 15–30 minutes: advise patient to remain near toilet. If no effect after 30 minutes, may repeat once.

Contraindications

  • Bowel obstruction
  • Rectal fissure or fistula (relative — use with care)
  • Inflammatory bowel disease with rectal involvement (relative)

Side effects

  • Rectal irritation and discomfort (mild — glycerol is mildly hygroscopic)
  • Abdominal cramping (mild)
  • Diarrhoea (if overused)

Interactions

  • No clinically significant drug interactions

Monitoring

  • Stool consistency and frequency
  • Rectal comfort

Reference: BNFc; BNF 90; BNF for Children 2024; NICE NG128 Constipation. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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