What is the best treatment for constipation?

Best Treatment for Constipation

The best treatment for constipation combines osmotic laxatives (polyethylene glycol, lactulose) or stimulant laxatives (senna, bisacodyl) as first-line pharmacological therapy, alongside non-pharmacological measures including increased fluid intake, physical activity, and proper toileting habits. 1, 2

Initial Assessment

Before initiating treatment, perform a focused evaluation:

• Abdominal examination, perineal inspection, and digital rectal examination to identify fecal impaction or rectal masses 1, 2
• Check corrected calcium and thyroid function if clinically suspected as contributing factors 1, 2
• Plain abdominal X-ray may help visualize fecal loading and exclude bowel obstruction, though it has limited utility as a standalone tool 1
• Review all medications to identify and discontinue non-essential constipating agents 2, 3

Non-Pharmacological Management (Foundation for All Patients)

These measures should be implemented first but should not be the sole focus of management, as their impact is positive but limited 1:

• Ensure privacy and comfortable toileting environment with proper positioning (small footstool to assist gravity and pressure) 1, 2
• Increase fluid intake to at least 2 liters daily 2, 4
• Encourage physical activity and mobility within patient limits, even bed-to-chair transfers 1, 2
• Increase dietary fiber to 25 g/day only if fluid intake and activity are adequate 1, 2, 5
• Consider abdominal massage, particularly for patients with neurogenic bowel dysfunction 1, 2

First-Line Pharmacological Treatment

Osmotic laxatives are the preferred initial pharmacological option:

• Polyethylene glycol (PEG) 17g daily is the most effective and well-tolerated option, producing bowel movements in 1-3 days 1, 2, 3, 6
• Lactulose is an alternative osmotic agent 1, 2
• Magnesium salts can be used but must be avoided or used cautiously in renal impairment due to hypermagnesemia risk 1, 2

Stimulant laxatives are equally appropriate as first-line therapy:

• Senna, bisacodyl (10-15 mg daily), or sodium picosulfate provide effective relief 1, 2, 3
• These agents are particularly useful for opioid-induced constipation 1, 2, 3

What NOT to Use

Avoid these common pitfalls:

• Docusate (stool softeners) are NOT recommended - multiple guidelines explicitly state inadequate evidence of benefit 3, 7
• Bulk laxatives (psyllium) are NOT recommended for opioid-induced constipation and should be avoided in non-ambulatory patients with low fluid intake due to obstruction risk 1, 3
• Liquid paraffin should be avoided in bedridden patients and those with swallowing disorders due to aspiration pneumonia risk 1, 2

Special Situations

Fecal Impaction

When digital rectal exam identifies a full rectum or impaction:

• Suppositories (glycerine, bisacodyl) or enemas are first-line therapy 1, 3
• Digital fragmentation and extraction followed by maintenance bowel regimen 1, 2
• Contraindications for enemas: neutropenia, thrombocytopenia, recent pelvic surgery/trauma, severe colitis, undiagnosed abdominal pain, recent pelvic radiotherapy 1

Opioid-Induced Constipation

All patients starting opioids require prophylactic laxatives unless contraindicated by pre-existing diarrhea:

• Osmotic or stimulant laxatives as first-line 1, 2
• Combined opioid/naloxone formulations reduce OIC risk 1
• For refractory cases: Peripherally acting μ-opioid receptor antagonists (PAMORAs) such as methylnaltrexone 0.15 mg/kg subcutaneously every 2 days 1, 2

Elderly Patients

Require particular attention to assessment and treatment selection:

• PEG 17g/day offers the best safety profile for elderly patients 1, 2
• Ensure toilet access, especially with decreased mobility 1, 2
• Monitor for dehydration and electrolyte imbalances when using diuretics or cardiac glycosides concurrently 1, 2
• Isotonic saline enemas are preferable over sodium phosphate enemas in older adults 1

Treatment Algorithm

1. Start with non-pharmacological measures (privacy, positioning, fluids, activity) 1, 2
2. Add osmotic laxative (PEG 17g daily) OR stimulant laxative (senna, bisacodyl) 1, 2, 3
3. If inadequate response: Combine osmotic + stimulant laxative 2, 3
4. For rectal impaction: Suppositories or enemas first 1, 3
5. For refractory cases: Consider newer agents (linaclotide, lubiprostone) or PAMORAs for opioid-induced constipation 1, 8

Key Clinical Pitfalls to Avoid

• Never rely on stool softeners alone - they lack efficacy evidence 3, 7
• Never use bulk laxatives without ensuring adequate fluid intake - risk of worsening obstruction 3
• Never forget prophylactic laxatives when prescribing opioids - this leads to significant patient discomfort and reduced adherence 3, 7
• Never use magnesium-based laxatives long-term in renal impairment - toxicity risk 1, 8