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Stimulant Laxative — Bowel Preparation Pregnancy: Use with caution in pregnancy — avoid in first trimester

Sodium Picosulfate

Brand names: Picolax, Dulcolax (oral drops)

Adult dose

Dose: Bowel prep: two sachets (Picolax) taken the day before surgery — first sachet morning, second sachet afternoon. Constipation: 5-10 mg once at night
Route: Oral
Frequency: Bowel prep: two doses day before; constipation: once daily
Max: Two Picolax sachets (combined with magnesium citrate) for bowel preparation
Each Picolax sachet contains sodium picosulfate 10 mg + magnesium oxide + citric acid (generates magnesium citrate in situ — osmotic + stimulant dual action). Ensure adequate fluid intake during preparation

Paediatric dose

Dose: Seek specialist opinion N/A/kg
Route: Oral
Frequency: Seek specialist opinion
Max: Seek specialist opinion
Seek specialist opinion for paediatric bowel preparation

Dose adjustments

Renal

Avoid Picolax if eGFR under 30 — magnesium accumulation risk; use alternative bowel preparation

Hepatic

Use with caution in hepatic impairment

Paediatric weight-based calculator

Seek specialist opinion for paediatric bowel preparation

Clinical pearls

  • Picolax dual mechanism: sodium picosulfate (stimulant — colonic motility) + magnesium citrate (osmotic — luminal water retention) produces thorough bowel cleansing with lower volume intake than PEG-based preparations
  • NICE CG99: Bowel preparation before elective colorectal surgery — evidence does not support routine mechanical bowel preparation for colonic surgery; however most centres use it for left-sided resections and rectal surgery
  • Dehydration risk: encourage 250 mL clear fluid per sachet plus additional clear fluids throughout; IV pre-hydration may be needed in frail or elderly patients
  • Electrolyte imbalance: check U&E before surgery in patients who have undergone bowel preparation — hypokalaemia is most common and clinically significant
  • Split-dose preparation (one sachet evening before, one sachet morning of surgery) improves colonoscopy quality — also being adopted for pre-surgical preparation at some centres

Contraindications

  • Bowel obstruction
  • Gastric retention
  • Severe dehydration
  • Severe renal impairment (eGFR under 30 — for Picolax formulation)
  • Congestive heart failure

Side effects

  • Nausea and vomiting
  • Abdominal cramps
  • Dehydration and electrolyte imbalance (hypokalaemia, hyponatraemia, hypermagnesaemia)
  • Exacerbation of IBD

Interactions

  • Antibiotics (may reduce bacterial conversion of picosulfate to active form — reduced efficacy)
  • Drugs absorbed in GI tract (rapid transit reduces absorption — avoid oral drugs during bowel prep period)

Monitoring

  • Fluid balance and hydration status
  • Electrolytes (U&E) before surgery
  • Bowel output (confirm adequate preparation)

Reference: BNFc; BNF 90; Picolax SPC; NICE CG99 (Colorectal Surgery); BSG Bowel Preparation Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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