PROTON PUMP INHIBITORS...
EXAMPLES: Omeprazole, lansoprazole, esomeprazole, pantoprazole.
MECHANISM OF ACTION: Inhibit H+/K+ ATPase on luminal surface of gastric parietal cells
and thereby reduce gastric acid secretion.
- Gastric/duodenal ulceration.
- As part of triple therapy for eradication of Helicobacter pylori.
- Gastro-oesophageal reflux disease.
- Acid-related dyspepsia.
- Hyper-secretory conditions, including Zollinger-Ellison syndrome.
- Prevention and treatment of NSAID-associated ulcers.
- Hypersensitivity.
- If red flag features of malignancy need to investigate prior to initiating treatment.
- GI disturbance (e.g. abdominal pain, nausea, vomiting, diarrhoea).
- Increased risk of gastric infections due to hypochlorhydria.
- Extensively metabolised by liver and excreted by both renal and biliary routes. t½ varies from 40 min to 2 h.
- No specific drug monitoring required.
- PPIs are inducers of Cytochrome P450 with some variation in potency between the individual drugs and, therefore, may enhance effects of drugs metabolised by the liver (e.g. phenytoin, carbamazepine, warfarin).
- PPIs reduce acid secretion by > 90% and are therefore more effective at healing peptic ulcers than H2 receptor antagonists (which reduce acid secretion by 50–60%).
- IV PPIs can be used in the management of acute upper GI bleeds under specialist supervision.