ModerateProton pump inhibitors×Water-soluble B-vitamin; cofactor of methionine synthase and methylmalonyl-CoA mutase
Updated · Methodology
Mechanism
Food-bound vitamin B12 comes attached to protein and needs acid and pepsin to be released. Without acidity that release fails, and NIH ODS names gastric acid inhibitors among medications that affect B12 status. Supplemental B12 arrives already free and barely depends on pH, which is why the answer is to supplement rather than stop the drug.
Symptoms
Fatigue, tingling in hands and feet, difficulty concentrating, a smooth, sore tongue. Macrocytic anaemia comes late: neurological symptoms can precede an abnormal blood count.
Management
After 2–3 years on an inhibitor, measure serum B12 and, if borderline, methylmalonic acid. High-dose oral B12 works even without gastric acid, so the intramuscular route is rarely needed for this reason. Vegetarians and people over 65 start with less reserve and deserve earlier testing.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
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Sources
- AEMPS: Ficha técnica Esomeprazol Cinfa 20 mg cápsulas gastrorresistentes EFG (2024)– AEMPS, CIMA, nº registro 82921, secciones 4.4 y 4.8
- NIH Office of Dietary Supplements: Vitamin B12 – Health Professional Fact Sheet (2025)– NIH ODS, Vitamin B12, Interactions with Medications