PPIs

• e.g. omeprazole, lansoprazole

Main indications

• Prevention and treatment of peptic ulcer disease
• Symptomatic relief of dyspepsia and GORD
• Eradication of H. pylori infection
  • Omeprazole + clarithromycin and amoxicillin OR metronidazole
• Zollinger-Ellison syndrome

Mechanism of action

• Irreversibly inhibit the gastric gland parietal cell H+/K+-ATPase (‘proton pump’) to reduce HCl secretion
  • This is the final common pathway by with all secretagogues (e.g. ACh, gastrin, histamine) increase gastric acid production
• PPIs are prodrugs – activated in the acidic environment of the canaliculus

Contraindications and cautions

• Use with caution in patients at risk of osteoporosis - should maintain an adequate intake of calcium and vitamin D
• May mask symptoms of gastric cancer - malignancy should be ruled out in patients with 'red flags' before starting treatment

Adverse effects

• Generally safe
• Diarrhoea (especially lansoprazole), headache, abdominal pain, nausea, fatigue and dizziness are common
• Increased stomach pH reduces defences against infection via the GI tract

Administration

• PO (once daily) or IV

H2 receptor antagonists