Makindo Medical Notes

⚡ Sodium Picosulfate is a stimulant laxative that works at the level of the colon to increase peristalsis and accelerate stool transit. It is pharmacologically similar to bisacodyl but acts after bacterial activation in the gut, typically within 6–12 hours.

🧠 About

• A pro-drug that becomes active only after conversion by colonic bacteria to bis-(p-hydroxyphenyl)-pyridyl-2-methane (BHPM).
• Belongs to the diphenylmethane class, like bisacodyl, but is usually better tolerated.
• Commonly used for short-term constipation or as part of bowel-cleansing regimens before colonoscopy or surgery.
• Onset: oral 6–12 h (best taken at night for a morning bowel movement).

⚙️ Mode of Action

• After activation by gut flora, it stimulates the myenteric plexus in the colon, enhancing peristaltic contractions.
• Increases intestinal secretion of water and electrolytes, softening stool and speeding colonic transit.
• Acts locally in the colon with minimal systemic absorption.

🎯 Indications and Dose

• Constipation: 5–10 mg once daily by mouth (usually at night).
• Bowel preparation: used in combination with magnesium citrate or other agents according to local protocols (see product-specific regimens).
• Adjust dose to produce one soft bowel motion daily. Avoid long-term continuous use.

⚠️ Cautions

• Maintain adequate hydration to avoid dehydration and electrolyte loss.
• Use cautiously in frail or elderly patients — risk of hypokalaemia if overused.
• Stop if severe abdominal pain, vomiting, or diarrhoea occur.
• Use with caution in inflammatory bowel disease due to risk of mucosal irritation.

🚫 Contraindications

• Intestinal obstruction or acute surgical abdomen.
• Severe dehydration or electrolyte imbalance.
• Active inflammatory bowel disease (especially ulcerative colitis flare).

💊 Adverse Effects

• Abdominal cramps and diarrhoea (dose-related).
• Nausea or vomiting.
• Occasional dizziness, colitis, or skin rash.
• Chronic overuse → electrolyte loss and “cathartic colon.”

🤰 Pregnancy and Lactation

• Limited systemic absorption — safe for short-term use in pregnancy if other laxatives ineffective.
• Minimal transfer into breast milk; generally compatible with breastfeeding.

🩺 Practical Prescribing Tips

• Prefer taken at bedtime for morning effect.
• Often combined with osmotic agents (e.g. macrogol) for opioid-induced constipation.
• Monitor fluid balance if diarrhoea occurs, particularly in older adults.
• Review need regularly — aim for short courses, not long-term dependence.

💡 Teaching Pearls

• Compare to Bisacodyl — both converted to BHPM, but bisacodyl acts via hydrolysis, picosulfate via bacterial activation.
• Picosulfate is gentler on the stomach, as it avoids direct mucosal irritation in the upper gut.
• Useful teaching analogy: “💊 Bisacodyl is instant; 🌿 Picosulfate is patient-friendly.”

📚 References

• BNF: Sodium Picosulfate
• NICE CKS: Constipation in adults (2024)
• Camilleri M. NEJM 2021; 385: 488–498 — Mechanisms and Management of Constipation