Checked between Vitamin B12 and Acid blockers.
Acid blockers — Omeprazole, lansoprazole, famotidine
This is one pairing. If you take more than these two things, run everything through the interaction check at once.
This covers a commonly documented interaction at the level of drug classes — not your dose, not your health history. A clear result here is not clearance. Before starting, stopping, or changing anything, talk to a pharmacist or prescriber.