From the databaseWhat the row says.
Every entry follows the same shape: what is happening, the mechanism, and the recommendation.
Scope
Supplement × Prescription
Last verified
June 4, 2026
CautionModerate evidence
What is happening. Rabeprazole can reduce absorption of food-bound vitamin B12 during prolonged therapy.
Mechanism. Gastric acid suppression impairs release of protein-bound B12 from food.
Recommendation. Monitor B12 status during long-term therapy or symptoms of neuropathy, anemia, or cognitive change; oral crystalline or sublingual B12 may still be effective.
Stack Score
How it moves the number.
Effect on the composite score
If both Rabeprazole and Vitamin B12 are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are at /methodology/stack-score.
SourcesSources, by evidence tier.
Every claim on this page is cited. PMIDs link straight to PubMed.
Reference material
1- 1Lam JR et al. Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency. JAMA. 2013.Needs sourceNo link