Magnesium citrate with sodium picosulfate

How it works

Sodium picosulfate is a stimulant laxative activated by colonic bacteria to directly stimulate the mucosa and increase motility, while magnesium citrate provides an osmotic effect that retains water in the lumen; together they produce a thorough purge.

Prescribing in practice

• As with all bowel-cleansing agents it carries a real risk of dehydration and electrolyte disturbance, so it is contraindicated in gut obstruction or perforation, ileus, toxic colitis and severe dehydration, and the magnesium component warrants caution in renal impairment.
• Generous clear-fluid intake during cleansing is essential, with particular care in elderly, frail or cardiac patients.
• Because picosulfate requires colonic bacteria for activation, concurrent antibiotics may reduce its effectiveness.

Monitoring

Check or consider renal function and electrolytes before use in at-risk patients, and ensure hydration is maintained throughout the cleansing process.

Counselling the patient

• Take each dose at the times instructed and drink large amounts of clear fluid to stay hydrated.
• Expect watery diarrhoea within hours and stay near a toilet.
• Seek advice if you develop fainting, palpitations, severe pain or persistent vomiting.

Evidence & guidelines

Sodium picosulfate with magnesium citrate is a well-established bowel-preparation regimen in UK endoscopy practice, with safe use guided by attention to hydration and electrolytes.