Geriatric Syndrome
Constipation in Older Adults: Workup & Treatment
Constipation affects up to 40% of community-dwelling older adults and is a frequent driver of urgent care visits, delirium, urinary retention, and avoidable hospitalizations. Causes are usually multifactorial — medications (opioids, calcium channel blockers, anticholinergics, iron, calcium), dehydration, low fiber, immobility, and conditions like Parkinson's, hypothyroidism, and diabetes. Red flags including new onset after age 50, hematochezia, weight loss, iron deficiency anemia, or change in stool caliber warrant colonoscopy. This page covers Rome IV criteria, a structured medication review, the role of fiber and hydration, osmotic agents (PEG 3350 first-line), stimulant laxatives, secretagogues, and disimpaction approaches for severe cases. Includes guidance on bowel regimens for opioid users and when to refer for pelvic floor dysfunction or anorectal manometry.
Full clinical workflow, red flags, dosing, and documentation below. Subscribe to read the full guide.
Constipation
Constipation
PEG first-line · Opioid bowel regimen day 1 · Screen for red flags.
Assessment
How to identify in clinic
- Ask about frequency, consistency (Bristol Stool Scale), straining, incomplete evacuation
- Rome IV criteria: 2+ of straining, lumpy/hard, incomplete evacuation, obstruction, manual maneuvers, <3/week
- Abdominal exam — distension, tenderness, palpable stool
- Rectal exam — impaction, masses, tone, occult blood
Common causes in older adults
- Medications — opioids, calcium channel blockers, anticholinergics, iron, calcium supplements
- Dehydration and low fiber intake
- Immobility / reduced physical activity
- Hypothyroidism, hypercalcemia, hypokalemia
- Parkinson's disease, diabetes (autonomic neuropathy)
- Pelvic floor dysfunction
Red flags requiring further workup
- New onset after age 50 — colonoscopy if not up to date
- Hematochezia, unintentional weight loss, iron deficiency anemia
- Change in stool caliber
Management
Step 1 — Lifestyle & bulk
- Increase fluid intake (if not fluid-restricted)
- Fiber 20–30 g/day — increase gradually to avoid bloating
- Physical activity — even walking helps
- Toilet routine — sit 15–20 min after meals (gastrocolic reflex)
Step 2 — Osmotic laxatives
- Polyethylene glycol (MiraLAX) 17 g daily — first-line pharmacotherapy
- Lactulose 15–30 mL daily — alternative, may cause bloating
Step 3 — Stimulant laxatives
- Senna 8.6–17.2 mg at bedtime
- Bisacodyl 5–10 mg PRN
- Opioid-induced: start senna WITH the opioid — do not wait
Step 4 — Refractory
- Linaclotide 145 mcg daily (IBS-C / chronic constipation)
- Methylnaltrexone (opioid-induced, refractory to laxatives)
- Manual disimpaction if fecal impaction
Refer & Document
When to refer
- GI — refractory to 2+ agents, red flags, suspected pelvic floor dysfunction
- Colorectal surgery — if obstruction suspected
- Pelvic floor PT — dyssynergic defecation
Documentation must include
- Bowel pattern and Bristol Stool Scale type
- Medication review for constipating drugs
- Rectal exam findings
- Red flag assessment
- Step-wise treatment plan
Dangerous Pitfall
Never start an opioid without a bowel regimen. Opioid-induced constipation does NOT resolve on its own — tolerance does not develop to this side effect. Start senna on day 1. Fecal impaction from unmanaged opioid constipation can cause delirium, urinary retention, and bowel obstruction.
Evidence sources
- · ACG Chronic Constipation Guidelines 2021
- · AGS Beers Criteria 2023
Review status
Last reviewed: 2026-04
Reviewed by the MyClinicianGuide editorial team. Cadence: annual.
Educational reference for licensed clinicians (NP, PA, MD, DO). Not a substitute for clinical judgment, institutional protocols, or specialty consultation. Apply in context of the full clinical picture, patient goals, and current standards of care. See About AI guidance for AI-related limitations.
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