Chronic Constipation in Adults
On this page
Direct answer
Rome IV asks for at least two of six features — straining, hard or lumpy stools (Bristol 1–2), incomplete evacuation, anorectal obstruction sensation, manual manoeuvres, and fewer than three spontaneous bowel movements weekly — each present in at least a quarter of defecations, over the last three months, with onset at least six months ago, and without loose stools except with laxatives. Management is genuinely stepwise: dietary fibre and fluids, osmotic laxatives (polyethylene glycol first), then stimulant laxatives, then prescription agents — prucalopride, lubiprostone, linaclotide — with red flags dictating colonoscopy at the start.
What you must remember
- Rome IV payload: symptoms on ≥25% of defecations for 3 months, onset ≥6 months; if loose stools occur without laxatives, think IBS-C instead.
- Red flags for colonoscopy: new-onset constipation after age 50, rectal bleeding, anaemia, weight loss, nocturnal symptoms, family history of colorectal cancer, refractory symptoms despite adequate therapy.
- First-line: fibre 25–30 g/day with adequate fluids, escalated slowly; polyethylene glycol (PEG) is the preferred osmotic — tasteless, safe, no electrolyte shifts; lactulose is the alternative (flatulence limits it).
- Stimulants are not forbidden: bisacodyl, sodium picosulfate and senna are safe long-term; the old "cathartic colon"/nerve-damage dogma is not supported by modern evidence — a favourite myth question.
- Second-line agents: prucalopride (selective 5-HT4 agonist, 1–2 mg daily), lubiprostone (chloride channel opener), linaclotide (guanylate cyclase-C agonist); all increase secretion or propulsion.
- Opioid-induced constipation: stimulants plus peripherally acting antagonist naloxegol; laxatives alone often fail.
- Faecal impaction: high-dose PEG orally (or enemas/suppositories distally); manual disimpaction if needed.
- Indian setting: refined, low-fibre diets and low fluid intake dominate; medication review (opioids, iron, calcium-channel blockers, anticholinergics) precedes escalation.
The laxative ladder in practice
Walk it as a 45-year-old woman with years of straining and hard stools, no red flags. Step one is education and fibre — 25–30 g daily built up over weeks, because jumping straight to full doses causes bloating and the patient abandons it. Step two, if fibre at 4–6 weeks fails, is PEG 17 g daily, titrated to one soft stool daily; lactulose substitutes if cost or taste matters. Step three adds or switches to a stimulant (sodium picosulfate at night, bisacodyl in the morning) — reassure the patient that long-term stimulant use is safe. Only after all three steps over months does prucalopride 1 mg (up to 2 mg) daily enter. Alongside every step, check the drug list and ask directly about anorectal symptoms: a sensation of blockage or digitation points to pelvic floor dyssynergia, which needs anorectal manometry and biofeedback rather than more laxatives. The ladder fails most often because each step is given a few days instead of the 4–8 weeks it deserves.
The traps the exam sets
The classic trap is the false dichotomy of "habitual" versus organic constipation — the examiner wants the red-flag list recited, not a vague reassurance. Second, IBS-C versus functional constipation hinges on pain: in IBS-C abdominal pain is prominent and improves with defecation; in functional constipation discomfort is not the leading symptom. Third, the stimulant-laxative myth appears as a true/false stem — modern evidence holds chronic stimulant use safe, with no demonstrable neurodegeneration at recommended doses. Finally, remember that hypothyroidism and hypercalcaemia belong in the first screen of any severe case: TSH and serum calcium before you blame diet alone.
Frequently asked questions
What are the Rome IV criteria for chronic constipation?
At least two of six features — straining, hard stools, incomplete evacuation, obstruction sensation, manual manoeuvres, fewer than three spontaneous bowel movements weekly — on ≥25% of defecations for 3 months, with onset ≥6 months earlier.
Which laxative is first-line?
Polyethylene glycol, an osmotic agent, after dietary fibre and fluid optimisation; it is effective, well tolerated and safe for long-term use.
Do stimulant laxatives damage the colon?
No — despite the historical "cathartic colon" belief, current evidence shows chronic stimulant use at recommended doses is safe and effective; this is a classic myth-buster.
When is colonoscopy indicated in constipation?
For red flags — new symptoms after 50, bleeding, anaemia, weight loss, nocturnal symptoms, family history of colorectal cancer, or failure of adequate treatment.
How is opioid-induced constipation managed?
Scheduled stimulant plus osmotic laxative, with a peripherally acting mu-opioid antagonist such as naloxegol when standard laxatives fail.