What are the effective medications for managing constipation?

Effective Medications for Constipation

Polyethylene glycol (PEG) 17g daily is the first-line pharmacological treatment for chronic constipation, with a strong recommendation based on moderate-quality evidence. 1

First-Line Treatment Approach

Start with PEG as primary therapy:

• PEG 17g daily is strongly recommended over no treatment for chronic idiopathic constipation, with proven durability over 6 months 1
• Cost-effective at $10-45 per month 1
• Common side effects include abdominal distension, loose stool, flatulence, and nausea 1
• No clear maximum dose; titrate based on symptom response 1

Fiber supplementation (psyllium) can be considered:

• Conditional recommendation with low-quality evidence 1
• Most effective fiber is psyllium at 14g/1,000 kcal intake per day 1
• Requires adequate hydration to prevent worsening symptoms 1
• Works best with doses >10g/day and treatment duration ≥4 weeks 2
• Flatulence is common and may limit tolerability 1, 2
• Consider for mild constipation or in combination with PEG 1

Second-Line Options When First-Line Fails

Magnesium oxide:

• Conditional recommendation with very low-quality evidence 1
• Start at 400-500mg daily, can increase if necessary 1
• Contraindicated in renal insufficiency due to hypermagnesemia risk 1
• Cost <$50 per month 1

Lactulose:

• Conditional recommendation for patients who fail or are intolerant to over-the-counter therapies 1
• Start at 15g daily 1
• Only osmotic agent studied in pregnancy 1
• Bloating and flatulence may be limiting at higher doses 1
• Cost <$50 per month 1

Stimulant Laxatives for Short-Term/Rescue Use

Bisacodyl and senna:

• Bisacodyl 5-10mg daily or senna 8.6-17.2mg daily 1
• Recommended for short-term use or rescue therapy only 1
• Long-term safety and efficacy unknown 1
• Side effects include cramping, abdominal discomfort, and potential electrolyte imbalance with prolonged use 1
• Cost <$50 per month 1

Prescription Secretagogues for Refractory Cases

When over-the-counter options fail, consider prescription agents:

Lubiprostone (chloride channel activator):

• 24mcg twice daily for chronic idiopathic constipation 1, 3
• Strong recommendation with moderate-quality evidence for IBS-C 1
• Less likely to cause diarrhea than other secretagogues 1
• Nausea is frequent side effect; take with food and water to reduce nausea 3
• May benefit abdominal pain 1
• Cost approximately $374 per month 1

Linaclotide (guanylate cyclase-C agonist):

• 72-145mcg daily, can increase to 290mcg daily 1
• Strong recommendation with high-quality evidence for IBS-C 1
• Likely most efficacious secretagogue available 1
• Diarrhea is common side effect 1
• May benefit abdominal pain 1
• Cost approximately $523 per month 1

Plecanatide (guanylate cyclase-C agonist):

• 3mg daily 1
• Strong recommendation with high-quality evidence for IBS-C 1
• Diarrhea frequency similar to linaclotide 1
• Cost approximately $526 per month 1

Prucalopride (5-HT4 agonist):

• 1-2mg daily, maximum 2mg daily 1
• May have additional benefit for abdominal pain 1
• Headaches and diarrhea may occur 1
• Cost approximately $563 per month 1

Special Considerations

Opioid-induced constipation:

• Prophylactic bowel regimen is mandatory; patients do not develop tolerance to opioid-induced constipation 1
• Start with stimulant laxative with or without stool softener or PEG 1 capful with 8oz water twice daily 1
• Stool softeners alone (docusate) are less effective than laxatives alone 1
• If persistent despite laxatives, consider methylnaltrexone 0.15mg/kg subcutaneously as rescue therapy when constipation is clearly opioid-related 1
• Lubiprostone 24mcg twice daily is FDA-approved for opioid-induced constipation in chronic non-cancer pain 3

Hepatic impairment:

• Moderate impairment (Child-Pugh B): Reduce lubiprostone to 16mcg twice daily 3
• Severe impairment (Child-Pugh C): Reduce lubiprostone to 8mcg twice daily 3

Common pitfalls to avoid:

• Do not use supplemental medicinal fiber (psyllium) without adequate hydration 1
• Avoid magnesium-based products in renal insufficiency 1
• Do not rely on stool softeners alone; they are ineffective as monotherapy 1
• Stimulant laxatives should not be used long-term due to unknown safety profile 1