IBS-C Treatment Guidelines

First-Line Treatment Options

• The American Gastroenterological Association recommends soluble fiber (ispaghula/psyllium) as a first-line treatment at 3-4 g/day initially, gradually increasing to an optimal dose of 20 g/day to avoid bloating 1, 3
• Polyethylene glycol (PEG) may be an effective treatment for constipation in IBS, though abdominal pain is a common side effect 1
• Certain antispasmodics may be effective for global symptoms and abdominal pain in IBS-C 1

Lactulose Use in IBS-C

• Standard lactulose dosing is 15 g daily as an osmotic laxative 4
• Titration should be based on symptom response and side effects 4
• No clear maximum dose is established in guidelines 4

Second-Line Treatments for IBS-C

• Linaclotide (290 μg once daily) is strongly recommended as the most efficacious secretagogue for IBS-C, though diarrhea is a common side effect 2, 5
• Lubiprostone (8 μg twice daily) is recommended for IBS-C and may cause less diarrhea than other secretagogues, but nausea is a frequent side effect 2
• Plecanatide (3 mg daily) is another effective option for IBS-C 2, 5
• Tenapanor (50 mg twice daily) is effective for IBS-C but may not be available in many countries 2, 5

Important Considerations

• Bloating and flatulence are common side effects of lactulose that may limit tolerability, especially in IBS patients who already experience these symptoms 4
• Lactulose is the only osmotic agent extensively studied in pregnancy 4
• The European Society of Gastroenterology recommends considering tricyclic antidepressants as gut-brain neuromodulators for global symptoms and abdominal pain 1, 2