What are the common medications used to treat gastrointestinal disorders such as gastroesophageal reflux disease (GERD), peptic ulcer disease, inflammatory bowel disease (IBD), and irritable bowel syndrome (IBS)?

Common Medications Used in Gastroenterology Practice

Gastroesophageal Reflux Disease (GERD) and Peptic Ulcer Disease

Proton pump inhibitors (PPIs) are the drugs of choice for GERD and peptic ulcer disease, providing superior efficacy to H2-receptor antagonists in healing erosive esophagitis and peptic ulcers. 1, 2

PPI Therapy for GERD and Erosive Esophagitis

• Omeprazole 20 mg daily, lansoprazole 30 mg daily, pantoprazole 40 mg daily, or rabeprazole 20 mg daily are standard doses for healing erosive esophagitis in 4-8 weeks 1, 3
• PPIs heal erosive esophagitis in 67% of patients at 4 weeks and 81% at 8 weeks, compared to only 37% and 49% with H2-receptor antagonists 4
• For severe reflux with ulceration or stricture, use higher doses: omeprazole 40 mg, lansoprazole 60 mg, pantoprazole 80 mg, or rabeprazole 40 mg daily 3
• Itopride can be added to PPIs when acid suppression alone is insufficient for GERD symptoms, particularly for dysmotility-predominant symptoms 5

Peptic Ulcer Disease Management

• Standard-dose PPIs (omeprazole 20 mg, lansoprazole 30 mg, pantoprazole 40 mg, or rabeprazole 20 mg daily) for 2-4 weeks heal duodenal ulcers more effectively than H2-receptor antagonists 3
• Gastric ulcers require 4-8 weeks of standard-dose PPI therapy 1, 3

H. pylori Eradication

• Triple therapy: PPI (omeprazole 40 mg/day) + clarithromycin + amoxicillin for 7-14 days eradicates H. pylori in over 90% of cases 1, 6
• This combination significantly reduces duodenal ulcer recurrence 1

Irritable Bowel Syndrome (IBS)

IBS with Constipation (IBS-C)

For IBS-C, secretagogues and osmotic laxatives are first-line pharmacological options, with lubiprostone offering the best tolerability profile among secretagogues. 7

• Polyethylene glycol (PEG) laxatives are suggested as first-line therapy for constipation symptoms, with low cost and minimal adverse effects 8
• Lubiprostone 8 mcg twice daily (FDA-approved for women with IBS-C) has the lowest risk of diarrhea among secretagogues and improves both abdominal pain and bowel movements 7
• Linaclotide 290 mcg once daily is the most efficacious secretagogue but commonly causes diarrhea 7

IBS with Diarrhea (IBS-D)

Loperamide is the first-line antidiarrheal agent for IBS-D, though it primarily improves stool frequency and consistency rather than global symptoms. 8

• Loperamide (dose titrated to effect) reduces stool frequency effectively with minimal adverse effects, though it may not improve abdominal pain or bloating 8
• Rifaximin 550 mg three times daily for 14 days is effective for IBS-D, targeting potential microbiota disturbances 8
• Eluxadoline (75-100 mg twice daily) improves both abdominal pain and stool consistency but is contraindicated in patients with prior cholecystectomy, sphincter of Oddi problems, or pancreatitis 8
• Ondansetron (4-12 mg daily, titrated) improves urgency and stool consistency with constipation as the main side effect 8

IBS (All Subtypes)

Tricyclic antidepressants are effective second-line therapy for global IBS symptoms and abdominal pain across all IBS subtypes. 8

• Amitriptyline starting at 10 mg once daily at bedtime, titrated slowly to 30-50 mg daily provides modest improvement in global relief and abdominal pain 8, 9
• Careful patient education is required to explain their use as gut-brain neuromodulators rather than antidepressants 8, 9
• Caution in patients at risk for QT prolongation; mild sedation may be beneficial in some patients 8
• Selective serotonin reuptake inhibitors (SSRIs) are NOT recommended for IBS as they show no improvement in global symptoms or abdominal pain 8

Antispasmodics improve global IBS symptoms and abdominal pain with minimal adverse effects. 8

• Multiple agents available including dicycloverine, hyoscine butylbromide, mebeverine, and alverine 8
• Meta-analysis shows 35% reduction in persistent symptoms compared to placebo 8
• Can be used continuously or as needed, though evidence is based on continuous use 8

Functional Dyspepsia

Itopride is recommended as first-line therapy for dysmotility-like functional dyspepsia symptoms including postprandial fullness, early satiety, and bloating. 5

• Itopride (standard dosing per local availability) has an excellent safety profile with adverse event rates of only 1.5-3.1% and no cardiac toxicity 5
• Can be prescribed after H. pylori eradication in patients with persistent dysmotility symptoms 5
• Tricyclic antidepressants (amitriptyline 10 mg titrated to 30-50 mg daily) are indicated after failure of PPIs, H. pylori eradication, and prokinetics 9

Important Clinical Caveats

• PPI maintenance therapy is necessary for erosive esophagitis as relapse rates reach 80% at one year without continued treatment 10, 4
• Titrate tricyclic antidepressants slowly (10 mg/week or every 2 weeks) to minimize side effects of sedation, dry mouth, and constipation 8, 9
• Lubiprostone should be taken with food to minimize nausea, which is the most common side effect 7
• Screen for eating disorders before implementing restrictive diets in IBS patients using tools like the SCOFF questionnaire 8