What are the alternatives to Bentyl (dicyclomine) for managing irritable bowel syndrome (IBS) symptoms?

Alternatives to Bentyl (Dicyclomine) for Managing IBS Symptoms

Several effective alternatives to Bentyl (dicyclomine) exist for managing irritable bowel syndrome symptoms, with tricyclic antidepressants being the most strongly recommended second-line option for global symptom relief and abdominal pain. 1

First-line Alternatives

Dietary and Lifestyle Modifications

• Regular exercise is strongly recommended for all IBS patients 1
• First-line dietary advice should be offered to all patients 1
• Soluble fiber (ispaghula) is effective for global symptoms and abdominal pain, starting at 3-4g/day and gradually increasing to avoid bloating 1
• Low FODMAP diet can be considered as second-line dietary therapy, but should be supervised by a trained dietitian 1

Other Antispasmodics

• Certain antispasmodics may be effective for global symptoms and abdominal pain in IBS, though evidence quality is very low 1
• Common side effects include dry mouth, visual disturbance, and dizziness 1
• Options include mebeverine, alverine citrate, otilonium bromide, and pinaverium bromide 2

For IBS with Diarrhea

• Loperamide may effectively treat diarrhea in IBS (4-12 mg daily), but careful dose titration is needed to avoid side effects like abdominal pain, bloating, nausea, and constipation 1
• Codeine (15-30 mg, 1-3 times daily) is a reasonable alternative but more likely to cause sedation and dependency 1

Second-line Alternatives

Neuromodulators

• Tricyclic antidepressants are strongly recommended as effective second-line treatment for global symptoms and abdominal pain 1

  • Start at low dose (e.g., 10 mg amitriptyline once daily) and titrate slowly to 30-50 mg once daily 1
  • Careful explanation of rationale and counseling about side effects is required 1
  • Best avoided if constipation is a major feature 1

• Selective serotonin reuptake inhibitors may be effective for global symptoms 1

  • Evidence quality is lower than for tricyclic antidepressants 1
  • Options include citalopram, fluoxetine, and paroxetine 3

For IBS with Diarrhea

• 5-HT3 receptor antagonists are efficacious second-line drugs 1

  • Ondansetron (titrated from 4 mg once daily to maximum 8 mg three times daily) is a reasonable option 1
  • Constipation is the most common side effect 1
  • This drug class is likely the most efficacious for IBS with diarrhea 1

• Eluxadoline (mixed opioid receptor drug) is efficacious but contraindicated in patients with prior sphincter of Oddi problems, cholecystectomy, alcohol dependence, pancreatitis, or severe liver impairment 1

• Rifaximin (non-absorbable antibiotic) is efficacious but has limited effect on abdominal pain 1

For IBS with Constipation

• Linaclotide (guanylate cyclase-C agonist) is strongly recommended as an efficacious second-line drug 1, 4

  • Likely the most efficacious secretagogue for IBS with constipation 1
  • Diarrhea is a common side effect 1

• Lubiprostone (chloride channel activator) is strongly recommended as an efficacious second-line drug 1, 5

  • Less likely to cause diarrhea than other secretagogues 1
  • Nausea is a frequent side effect 1

• Plecanatide and tenapanor are also efficacious but may cause diarrhea 1

• Tegaserod (5-HT4 receptor agonist) is efficacious but has limited availability outside the USA 1

Practical Considerations

• When switching from Bentyl, consider the predominant IBS subtype (diarrhea, constipation, or mixed) to guide therapy selection 6
• For global symptom relief, tricyclic antidepressants have the strongest evidence 1
• Combination therapy may be necessary for patients with multiple symptoms 3
• Always start medications at low doses and titrate slowly to minimize side effects 1
• Monitor for treatment response and adjust therapy accordingly 1

Common Pitfalls to Avoid

• Avoid insoluble fiber (e.g., wheat bran) as it may exacerbate symptoms 1
• Avoid gluten-free diets unless celiac disease is confirmed 1
• Food elimination diets based on IgG antibodies are not recommended 1
• When prescribing tricyclic antidepressants, clearly explain they are being used for gut-brain modulation, not depression 1
• Be cautious with eluxadoline in patients with risk factors for sphincter of Oddi dysfunction 1