Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Omeprazole was the first proton pump inhibitor (PPI): it switches off the pumps in the stomach lining that release acid. It is used for heartburn and acid reflux, for stomach and duodenal ulcers, and as part of the treatment that clears Helicobacter pylori. It is sold as Prilosec and Losec, among other names, and in many countries without prescription.
Omeprazole is broken down mainly by the liver enzyme CYP2C19, and its blood levels differ several-fold between people with different gene versions. Poor and intermediate metabolizers keep it longer and their stomach acid stays lower, which studies link to better ulcer healing and Helicobacter cure; people with the fast *17 version clear it more quickly. CPIC and DPWG have published guidelines on CYP2C19 and omeprazole, and the US FDA lists an effect on drug levels. A few other genes such as IL1B have been studied, with weaker evidence.
Clinical guidelines that name a gene for Omeprazole. They sort people into groups by the gene copies they carry.
Every published finding on gene variants and Omeprazole. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
CYP2C19 CYP2C19*1, CYP2C19*2, CYP2C19*3, CYP2C19*9, CYP2C19*10, CYP2C19*17, CYP2C19*24, CYP2C19*26: Level 1A · replicated. Metabolism/PK: Gastroesophageal Reflux. 28.
CYP2C19 CYP2C19*1, CYP2C19*2, CYP2C19*3: Level 1A · replicated. Efficacy: Esophagitis, Gastroesophageal Reflux, Helicobacter Infections, Peptic Ulcer Disease. 27.
IL1B rs16944: Level 3. Efficacy: Helicobacter Infections. 3.
CYP2C19 CYP2C19*1, CYP2C19*23, CYP2C19*29, CYP2C19*30, CYP2C19*31, CYP2C19*33: Level 3. Metabolism/PK. 2.
Studies of how quickly the body processes this medication.
Studies of how well it worked in people carrying a variant.
Studies of how much of the drug people needed or tolerated.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
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