How Vitamin B12 interacts with Antibiotics

Interaction type: Depletions

Interaction rating: Study Supported

Studies have reported that the use of antibiotics is known to decrease the beneficial bacteria in the digestive tract, which may decrease the amount of the vitamin B12 that is normally made. Supplementation with the affected nutrient may be necessary. (1) (2)

These drugs include Aminoglycosides, Cephalosporins, Fluoroquinolones, Quinolones, Macrolides, Penicillins, Sulfonamides, Tetracyclines, Trimethoprin-containing antibiotics, Carbapenems, Monobactams, chloramphenicol, spectinomycin, Streptogramins, vancomycin, Oxalodinones, Lincosamides, Nitrofurans


  1. View Abstract: Cummings JH, Macfarlane G. Role of Intestinal Bacteria in Nutrient Metabolism J Parenter Enteral Nutr. 1997;21(6):357-65.
  2. Deguchi Y, Morishita T, Mutai M. Comparative Studies on Synthesis of Water-soluble Vitamins Among Species of Bifidobacteria. Agric. Biol. Chem. 1985;49(1):13-19.