Gastritis Treatment
The recommended first-line treatment for gastritis is H. pylori eradication therapy using a 14-day regimen of proton pump inhibitor (PPI) twice daily, amoxicillin 1g twice daily, and clarithromycin 500mg twice daily (standard triple therapy) for patients with confirmed H. pylori infection. 1
Diagnosis and Initial Assessment
- Patients >45 years with severe symptoms or any patients with alarm symptoms (anemia, weight loss, dysphagia, palpable mass, malabsorption) should be referred for endoscopy before treatment 1
- Younger patients (<45 years) without alarm symptoms can be managed in primary care with H. pylori testing and eradication 1
- Testing for H. pylori is indicated especially for patients with dyspepsia 1
Treatment Algorithm
1. H. pylori-Associated Gastritis
First-line therapy: 14-day standard triple therapy
For penicillin allergy: 14-day bismuth quadruple therapy
- PPI twice daily
- Bismuth 300mg four times daily
- Tetracycline 500mg four times daily
- Metronidazole 500mg three times daily 1
In areas with high clarithromycin resistance (>15-20%): Avoid clarithromycin-based regimens 1
If first-line treatment fails: Consider levofloxacin-based regimen
- PPI twice daily
- Bismuth 300mg four times daily
- Levofloxacin 500mg once daily
- Tetracycline 500mg four times daily, for 14 days 1
2. Non-H. pylori Gastritis (including NSAID-induced)
- PPI therapy for 4-8 weeks 1, 2
- For NSAID-associated gastritis, PPIs have efficacy advantages over ranitidine and misoprostol 1
Treatment Duration and Follow-up
- Confirm H. pylori eradication at least 4 weeks after completion of treatment using:
- Urea breath test (UBT) - gold standard with 95% sensitivity, 90% specificity, or
- Laboratory-based validated monoclonal stool antigen test 1
- Ensure patient has been off PPI for at least 2 weeks before testing 1
- For active duodenal ulcer: PPI therapy for 4 weeks 2
- For active gastric ulcer: PPI therapy for 4-8 weeks 2
Maintenance Therapy
- For uncomplicated duodenal ulcer: Prolonged PPI therapy is not required after successful H. pylori eradication 1
- For complicated duodenal ulcer: Continue PPI until H. pylori eradication is confirmed 1
- For erosive esophagitis: Long-term PPI maintenance therapy may be indicated 1
Special Considerations
- High-dose PPI increases the efficacy of triple therapy by 6-10% compared to standard doses 1
- 14-day regimens are superior to 7-day regimens, providing approximately 5% better eradication rates 1
- For patients with renal impairment (GFR 10-30 mL/min): Adjust amoxicillin dosing to 500mg or 250mg every 12 hours 1
- For patients with hepatic impairment: Consider reducing omeprazole dose to 10mg once daily 2
- For Asian patients: Consider reducing omeprazole to 10mg once daily due to approximately four-fold higher exposure compared to Caucasians 2
Patient Education
- Inform patients about potential side effects:
- Darkening of stool (from bismuth)
- Metallic taste
- Nausea and diarrhea
- Skin rash
- Muscle and joint pains 1
- Emphasize the importance of completing the full course of treatment 1
- Taking the regimen with meals may improve tolerance and efficacy 1
Pitfalls and Caveats
- PPIs can cause serious side effects including kidney problems (tubulointerstitial nephritis), C. difficile-associated diarrhea, bone fractures with long-term use, and certain types of lupus erythematosus 2
- Clarithromycin can increase serum levels of carbamazepine, potentially leading to toxicity in epileptic patients 3
- Long-term PPI use may cause corpus-predominant gastritis in H. pylori-infected patients, which is associated with gastric cancer 4
- Endoscopic follow-up is needed to ensure complete healing, and histological examination should be performed to exclude malignancy in cases of gastric ulcers 1