Omeprazole vs Lansoprazole

## Overview

Omeprazole and lansoprazole are both first-generation PPIs with similar mechanisms of action. They differ in CYP metabolism profile, drug interactions (notably different effects on clopidogrel), and available formulations.

## Mechanism of Action

Both are prodrugs activated in the parietal cell canaliculus to active sulfenamide species that covalently bind H+/K+-ATPase, irreversibly inhibiting proton pump function.

## Pharmacokinetics

Omeprazole: primarily CYP2C19 metabolism, minor CYP3A4. Lansoprazole: primarily CYP2C19 and CYP3A4 (more balanced between the two). Lansoprazole is available as a disintegrating tablet (SoluTab), which can be swallowed, placed under the tongue, or dissolved in water — useful in patients with dysphagia. Both have short plasma half-lives (~1–1.5 h) with acid suppression extending well beyond plasma levels.

## Drug Interactions (Clopidogrel)

Both inhibit CYP2C19 and reduce clopidogrel's active metabolite generation, blunting its antiplatelet effect. However, lansoprazole may have a smaller clopidogrel interaction than omeprazole/esomeprazole based on some PK studies, though FDA guidance warns about all PPIs with clopidogrel.

## Clinical Evidence

Both have equivalent efficacy for GERD, peptic ulcer disease, H. pylori eradication (as part of triple/quadruple therapy), and NSAID-induced ulcer prophylaxis. No head-to-head trial shows meaningful superiority of one over the other for standard indications.

## Key Takeaways

- Lansoprazole: orally disintegrating formulation (SoluTab) available
- Omeprazole: more potent CYP2C19 inhibitor; lansoprazole less so
- Both highly effective for acid-related disorders