Summary of the currently available pharmaceutical treatment options for irritable bowel syndrome (26)
| Treatment, by symptom | Mechanism of action | Dosage | Adverse effects | Relative risk of remaining symptomatic (95% CI) | No. needed to treat (95% CI) | Relative cost* |
|---|---|---|---|---|---|---|
| Constipation | ||||||
| Psyllium (ispaghula) | Bulk forming | 1 sachet (3.5 g) per day | Bloating, abdominal discomfort, diarrhea | 0.83 (0.73–0.94) | 7 (4–25) | $ |
| Polyethylene glycol | Osmotic laxative | 1–2 sachets per day (13.8 g per sachet) | Diarrhea, nausea, bloating | No dichotomous data available | No dichotomous data available | $$ |
| Linaclotide | Guanylate cyclase-C agonist | 290 μg once per day | Diarrhea, abdominal discomfort, gas, bloating | 0.81 (0.77–0.85) | 6 (5–8) | $$$ |
| Plecanatide | Guanylate cyclase-C agonist | 3 mg once per day | Diarrhea | 0.88 (0.84–0.92) | 10 (8–14) | $$$ |
| Lubiprostone | Type-2 chloride channel agonist | 24 μg twice per day | Diarrhea, headache, nausea | 0.91 (0.87–0.95) | 12.5 (8–25) | $$$ |
| Diarrhea | ||||||
| Loperamide | μ-Opioid receptor agonist | 2–4 mg up to 3 times per day | Constipation, abdominal pain | 0.44 (0.14–1.52) | Unknown | $ |
| Eluxadoline† | Mixed μ-opioid receptor and κ-opioid receptor agonist, and δ-opioid receptor antagonist | 75–100 mg twice per day | Constipation, abdominal pain, pancreatitis | 0.91 (0.85–0.97) | 12.5 (8–33) | $$$ |
| Pain | ||||||
| Antispasmodics (e.g., pinaverium) | Smooth muscle relaxant — calcium channel blocker | 50–100 mg once or twice per day | Stomach pain, fullness, nausea | 0.65 (0.56–0.76) | 5 (4–8) | $ |
| Peppermint oil | Smooth muscle relaxant | 1 capsule (0.2 mL) once or twice per day | Reflux, nausea, peppermint taste | 0.54 (0.39–0.76) | 4 (3–6) | $ |
| Tricyclic antidepressants (e.g., amitriptyline) | Centrally acting visceral pain modulation | 10 mg at night | Sleepiness, constipation, dry mouth | 0.65 (0.55–0.77) | 4 (3.5–7) | $$ |
| SSRIs (e.g., citalopram) | Centrally acting visceral pain modulation | 10 mg once daily | Diarrhea, memory problem, dry mouth | 0.68 (0.51–0.91) | 5 (3–16.5) | $$ |
| Modification of the microbiota | ||||||
| Rifaximin | Poorly absorbed antibiotic | 550 mg twice per day for 14 days | Nausea, vomiting, constipation | 0.86 (0.81–0.91) | 10.5 (8–16) | $$$ |
| Probiotics | Regulation of intestinal microbial homeostasis, gut mucosal barrier function | Varies depending on preparation | Gas and bloating | 0.81 (0.74–0.88) | 7 (5–12) | $$ |