Proton pump inhibitors, H2 antagonists and antacids
Expansion
- Proton pump inhibitors (omeprazole, lansoprazole): irreversibly inhibit the hydrogen-potassium ATPase, the final common pathway. Most effective
- H2 receptor antagonists (ranitidine, famotidine): block only the histamine arm
- Antacids and alginates: neutralise acid and form a raft
- Misoprostol: a prostaglandin analogue restoring mucosal defence; used for NSAID prophylaxis but causes diarrhoea and is an abortifacient
Long term proton pump inhibitor concerns: hypomagnesaemia, B12 and iron malabsorption, increased C difficile and community-acquired pneumonia risk, possible fracture risk, and interference with the absorption of drugs needing acid such as itraconazole. They also mask the symptoms of gastric malignancy, which is why alarm symptoms warrant endoscopy first, and they must be stopped 2 weeks before urease breath testing for H pylori.
H pylori eradication uses triple therapy: a proton pump inhibitor with two antibiotics, typically amoxicillin plus clarithromycin or metronidazole, for 7 to 14 days.
Gastroprotection should be co-prescribed with NSAIDs in those over 65, with previous ulcer, or on steroids, anticoagulants or antiplatelets.