PMCID: PMC11806371.
Understanding the Results The normal range for vitamin B12 can vary slightly depending on the lab
A class of peptic ulcer and antacid drugs called histamine H2 receptor agonists, including Tagamet, Zantac, and Pepcid Anticonvulsants including phenobarbital, primidone, and phenytoin Bile acid sequestrants including colestipol and cholestyramine, which lower cholesterol Chemotherapy medications like methotrexate Metformin, which is a diabetes drug Proton pump inhibitor drugs used to treat acid reflux, such as omeprazole (Prilosec), esomeprazole (Nexium), or lansoprazole (Prevacid) Tetracycline, an antibiotic Lastly, it is also essential that you communicate with your provider if you have kidney disease or an allergy to cobalt or any other medication, vitamin, dye, food, or preservative
Summary: True vitamin B12 overdose is exceptionally rare because it is water-soluble and excess amounts are excreted through urine rather than accumulating in body tissues