Sodium Picosulfate

How it works

After colonic bacteria cleave it to its active form, it stimulates the mucosa to increase peristalsis, while the magnesium citrate component acts osmotically to draw fluid into the bowel lumen, together producing a watery evacuation.

Prescribing in practice

• It causes large fluid and electrolyte shifts that can precipitate dehydration, hyponatraemia, hypokalaemia and acute kidney injury, so ensure generous clear-fluid intake and use great caution in the elderly, renally or cardiac impaired and those on diuretics, ACE inhibitors, ARBs or NSAIDs.
• Contraindicated in suspected intestinal obstruction or perforation, ileus, toxic megacolon, severe inflammatory bowel disease and significant heart failure or renal impairment.
• Separate the timing of other essential oral medicines, as rapid bowel transit can impair their absorption and reduce their effect.

Monitoring

Assess hydration and, where clinically indicated in at-risk patients, check renal function and electrolytes around the preparation period.

Counselling the patient

• Drink plenty of clear fluids throughout the preparation to avoid becoming dehydrated.
• Expect frequent watery diarrhoea and stay near a toilet once you start.
• Seek urgent advice if you develop severe headache, confusion, marked weakness or stop passing urine.

Evidence & guidelines

Sodium picosulfate with magnesium citrate is a standard, evidence-based bowel-cleansing regimen used across UK endoscopy and surgical units.