Constipation in the Elderly — Prevention and Management

Constipation is defined by difficult, infrequent or incomplete defecation. Rome IV criteria require two or more of straining, hard or lumpy stools, sensation of incomplete evacuation, sensation of anorectal blockage, manual manoeuvres, and fewer than three spontaneous bowel movements a week, for at least three months.

Complaints of constipation and laxative use are very common in older people. Twenty to thirty per cent of community-dwelling elders use laxatives at least weekly, and up to 50% of elderly women use them.

When comorbidities are controlled for, constipation is no more common in elders than in younger people. Stool frequency does not change with age — what elders complain of is straining and hard stools.

Colonic transit is generally well preserved with ageing. The change is in the pelvic floor — older women show reduced opening of the anorectal angle and greater perineal descent, and pudendal neuropathy becomes commoner.

Most causes relate to medication use or coexisting medical illness. The commonest drugs are opiates, calcium channel blockers (verapamil is the worst), NSAIDs and drugs with anticholinergic effects.

Diseases that contribute include diabetes mellitus, Parkinson's disease, stroke, hypothyroidism, hypercalcaemia, depression and dementia. Hysterectomy in women over 50 prolongs colonic transit.

Immobility and reduced fluid and fibre intake are traditionally blamed but the evidence is weak, and increased physical activity does not reliably improve constipation.

Changes can be mapped anatomically — central nervous system (awareness of the need to defecate: stroke, dementia, Parkinson's), peripheral nerves (pudendal injury), enteric nervous system (rectal desensitisation, diabetes), and skeletal muscle/incoordination (birth trauma, sphincterotomy, scleroderma).

Constipation reduces quality of life and self-perceived health, increases urinary frequency, urgency and dysuria, and worsens mood — all of which improve with treatment.

Faecal impaction is common — about 7% of institutionalised elderly have impacted faeces on rectal examination. The first sign may be overflow diarrhoea and rectal incontinence; if a rectal examination is not done, this is misdiagnosed and wrongly treated with antidiarrhoeals.

Immobile or cognitively impaired patients risk faecal impaction, stercoral ulceration and colonic perforation.

History, drug review and a digital rectal examination are mandatory. In patients whose colorectal cancer screening is up to date and who have no worrisome symptoms such as bleeding or weight loss, an empirical therapeutic trial is appropriate; investigate only those who fail to respond.

For non-responders: colonic transit study, anorectal manometry and balloon expulsion test, defecography, and a plain abdominal radiograph to assess stool burden.

Step 1 — review and stop constipating medications and substitute a less constipating alternative where one exists; then increase dietary fibre and fluid intake. Use the safest, best-tolerated and least expensive laxatives first.

Step 2 — bulking agents: bran 4–10 g, psyllium 3–6 g, methylcellulose 2–4 g, calcium polycarbophil 2–4 g, hydrolysed guar gum 3–6 g. Avoid bulking agents in faecal impaction, in bedbound patients and where fluid intake is poor. Side effects are bloating and flatulence.

Stool softeners such as docusate have no randomised evidence of efficacy — one trial showed no improvement over placebo and another found psyllium superior. Their therapeutic role is limited.

Step 3 — osmotic laxatives: polyethylene glycol (PEG) 17–34 g is the best tolerated in elders and improves both stool consistency and frequency. Lactulose 10–40 g and sorbitol 70% 15–60 mL are alternatives but cause bloating and cramps from bacterial fermentation. Magnesium and saline salts should generally be avoided — hypermagnesaemia occurs even with normal renal function; avoid in renal disease, end-stage liver disease and heart failure.

Step 4 — stimulant laxatives: senna 15 mg, bisacodyl 5–10 mg, sodium picosulfate 5–10 mg. In practice the commonest effective combination is an osmotic plus a stimulant laxative.

Secretagogue: lubiprostone 8–24 µg twice daily, a chloride channel activator, has good evidence in older people.

Opioid-induced constipation: peripherally acting mu-opioid receptor antagonists (PAMORAs) — methylnaltrexone, naloxegol and naldemedine — reverse constipation without reducing analgesia or precipitating withdrawal, and are superior to placebo. Methylnaltrexone is given by injection and is reserved for refractory symptoms. PEG and stimulant laxatives are also used.

Faecal impaction: give PEG or another osmotic laxative with or without enemas; a hard or large rectal bolus needs manual removal; water-soluble hyperosmotic contrast enemas may also relieve it. Bulking agents must be avoided.

Enemas: limit to acute situations and institutional care. Phosphate enemas cause serious hyperphosphataemia, particularly in renal impairment; soap-sud enemas should never be used. Small-volume tap water enemas are useful; large-volume ones can cause hyponatraemia; arachis oil retention enemas lubricate and soften impacted faeces (check nut allergy). Any enema carries a risk of colonic perforation.

Dyssynergic defecation: biofeedback is the established mainstay, given over four to six sessions, and improves defecatory function in about 70%. It is superior to diet, exercise, laxatives or diazepam. If both slow transit and dyssynergia coexist, treat with biofeedback first.

Refractory slow-transit constipation: nearly 90% respond to laxatives. Subtotal colectomy with ileorectal anastomosis is rarely needed and works best in patients without upper gut dysmotility or major psychological symptoms. Antegrade enemas through a caecostomy are an alternative.

Dementia: prevention is the preferred strategy because the patient may not recognise or communicate symptoms. Review drugs, increase fibre, fluid and activity, and use a regular osmotic laxative rather than rectal preparations. Non-verbal signs of the need to defecate include fidgeting, pacing and pulling at clothes; educate relatives and carers.

Stroke: constipation is associated with dependency, bedpan use for defecation, high NIHSS score, polypharmacy, dehydration and inactivity, and predicts a poor outcome at 12 weeks. Abdominal massage and visceral mobilisation improve frequency and reduce pain and incomplete evacuation.

Other agents: large randomised trials of probiotics have failed to show benefit. Misoprostol and colchicine are reserved for refractory cases and are limited by cramping. Neostigmine is reserved for acute colonic pseudo-obstruction in hospitalised patients.

Prevention: maintain mobility, use the gastrocolic reflex by toileting 20–30 minutes after meals, ensure privacy and an appropriate toilet position, provide a commode rather than a bedpan, keep hydration and fibre adequate, correct hypothyroidism and hypercalcaemia, and review the drug chart at every visit.

AGA–ACG Joint Clinical Practice Guideline on Chronic Idiopathic Constipation (Gastroenterology 2023;164:1086–1106; Am J Gastroenterol 2023;118:936) — ten GRADE-based recommendations, the first joint guideline of its kind.

Strong recommendations: polyethylene glycol (the only over-the-counter agent strongly recommended for chronic use), bisacodyl and sodium picosulfate (short-term, under 4 weeks, or as rescue therapy), and the prescription agents linaclotide, plecanatide and prucalopride after over-the-counter agents fail.

Conditional recommendations: fibre supplements (especially psyllium), magnesium oxide, lactulose, senna and lubiprostone. This was the first guideline to endorse magnesium oxide and senna as evidence-based options.

Docusate is not recommended — the guideline found no evidence of benefit, confirming long-standing geriatric teaching.

Prucalopride, a highly selective 5-HT4 agonist, has a reassuring cardiovascular safety profile (unlike cisapride and tegaserod) and is therefore acceptable in older adults; the guideline notes no signal of excess cardiovascular events.

Evaluate for a defecatory disorder before escalating drugs — oral agents work poorly in dyssynergic defecation; refer for anorectal manometry, balloon expulsion and pelvic floor biofeedback.

Newer options: the vibrating capsule (FDA-cleared, drug-free, uses vibration to stimulate colonic motility) is attractive in polypharmacy; elobixibat, an ileal bile acid transporter inhibitor, is available in some Asian markets; tenapanor (NHE3 inhibitor) is approved for IBS-C.

Opioid-induced constipation: network meta-analyses continue to support PAMORAs over placebo; oral naldemedine and naloxegol have largely replaced injectable methylnaltrexone for routine use, and are useful in palliative and cancer care in the elderly.

Constipation as a prodrome: accumulating cohort data confirm constipation may precede motor Parkinson's disease by 10–20 years and is associated with cognitive decline — it should prompt a neurological review rather than being dismissed.

Indian context: the Indian Society of Gastroenterology consensus and routine Indian practice place lactulose, PEG and ispaghula (isabgol) husk as the mainstays, chosen for cost and availability; linaclotide, prucalopride and lubiprostone are marketed in India but cost is a limiting factor. Rising urban prevalence is linked to low dietary fibre in refined-cereal diets, reduced physical activity and polypharmacy.