What medications are used to treat constipation?

Medications for Constipation

Start with polyethylene glycol (PEG) 17 g daily as first-line therapy for chronic constipation, as it is the most effective, cost-efficient, and well-tolerated option with proven long-term safety. 1, 2

First-Line Treatment: Osmotic Laxatives

Polyethylene Glycol (PEG) - Gold Standard

• PEG 17 g daily is the preferred initial treatment based on superior efficacy, safety profile, and cost-effectiveness ($10-$45/month) 1, 2
• Take once daily on an empty stomach, at least 30 minutes before a meal 3
• Titrate dose based on symptom response and side effects with no clear maximum dose 1, 2
• Response is durable over 6-12 months of continuous use 1, 4, 5
• Common side effects include bloating, abdominal discomfort, and cramping 1
• Ensure adequate hydration while using PEG 1

Alternative Osmotic Laxatives

• Magnesium oxide 400-500 mg daily can be used as an alternative, but use with caution in renal insufficiency and pregnancy 1
• Lactulose 15 g daily is another option and is the only osmotic agent studied in pregnancy, though bloating and flatulence may be limiting 1
• Meta-analysis shows PEG is superior to lactulose for stool frequency, stool form, and relief of abdominal pain 6

Fiber Supplementation

• 14 g fiber per 1,000 kcal daily intake can be added as adjunctive therapy 1
• Ensure adequate hydration as fiber intake increases 1
• Common side effects include bloating and abdominal discomfort 1

Second-Line Treatment: Stimulant Laxatives

Use stimulant laxatives for short-term use or rescue therapy when osmotic laxatives provide inadequate response. 1, 2

• Bisacodyl 5 mg daily (maximum 10 mg daily) is recommended for short-term use 1, 2
• Senna 8.6-17.2 mg daily (maximum 4 tablets twice daily) can be used, but long-term safety and efficacy are unknown 1, 2
• Both agents are recommended for short-term use or rescue therapy due to potential for cramping, abdominal discomfort, and electrolyte imbalance with prolonged use 1

Third-Line Treatment: Prescription Secretagogues

For refractory cases not responding to osmotic and stimulant laxatives, consider prescription secretagogues. 1, 2

Intestinal Secretagogues

• Lubiprostone 24 mcg twice daily acts on chloride channel type 2 in the gut and may provide additional benefit for abdominal pain ($374/month) 1, 2
• Linaclotide 72-145 mcg daily (maximum 290 mcg daily) is a guanylate cyclase-C agonist that may benefit abdominal pain ($523/month) 1, 2, 3
• Plecanatide 3 mg daily (no titration needed) is another guanylate cyclase-C agonist option ($526/month) 1, 2, 7
• Diarrhea may occur in a subset of patients with all secretagogues, leading to discontinuation 1

Prokinetic Agent

• Prucalopride 1-2 mg daily (maximum 2 mg daily) is a serotonin type 4 (5-HT4) receptor agonist that enhances colonic motility and may provide additional benefit for abdominal pain ($563/month) 1, 2
• Headaches and diarrhea may occur in some patients 1

Treatment Algorithm

1. Start with PEG 17 g daily as the most cost-effective option with best evidence for long-term use 1, 2
2. If inadequate response after 2-3 days, titrate PEG dose upward based on clinical response 2, 8
3. If PEG alone fails, add or switch to stimulant laxatives (bisacodyl or senna) for short-term use 1, 2
4. For refractory cases, consider prescription secretagogues (lubiprostone, linaclotide, plecanatide) or prokinetic agent (prucalopride) 1, 2

Critical Safety Warnings

• Do not give linaclotide to children less than 2 years of age - it can cause severe diarrhea and dehydration 3
• Do not give plecanatide to children less than 6 years of age - it may cause severe diarrhea and dehydration 7
• Do not use any laxatives in patients with bowel obstruction 3, 7
• Store secretagogue medications securely out of reach of children due to risk of severe diarrhea if accidentally ingested 3, 7