title: Omeprazole therapy causes malabsorption of cyanocobalamin (vitamin B12)
abstract: OBJECTIVE
  To evaluate protein-bound cyanocobalamin (vitamin B12) absorption before and after omeprazole (Prilosec) therapy in healthy male volunteers.
  
  
  METHODS
  Clinical trial in which each volunteer served as his own control.
  
  
  METHODS
  Outpatient department of a university medical center.
  
  
  METHODS
  Ten healthy, male volunteers 22 to 50 years old.
  
  
  METHODS
  Each participant had a modified Schilling test (protein-bound cyanocobalamin) and a gastric analysis, as well as measurements of serum vitamin B12, gastrin, and folate levels. Five patients were then randomly assigned to take either 20 mg or 40 mg of omeprazole daily. After 2 weeks of omeprazole therapy, these tests were repeated.
  
  
  METHODS
  The modified Schilling test, gastric analysis, serum gastrin level, folate level, and cyanocobalamin level.
  
  
  RESULTS
  At the end of the 2-week treatment period, cyanocobalamin absorption decreased from 3.2% to 0.9% (P = 0.031) in participants receiving 20 mg of omeprazole daily. In patients taking 40 mg of omeprazole daily, cyanocobalamin absorption decreased from 3.4% to 0.4% (P < 0.05).
  
  
  CONCLUSIONS
  Omeprazole therapy acutely decreased cyanocobalamin absorption in a dose-dependent manner.
authors.affiliation: Department of Medicine, East Carolina University School of Medicine, Greenville, NC 287858-4354.
authors.forename: S P
authors.initials: SP
authors.lastname: Marcuard
authors.forename: L
authors.initials: L
authors.lastname: Albernaz
authors.forename: P G
authors.initials: PG
authors.lastname: Khazanie
mesh_terms: D000328:Adult; D006801:Humans; D008286:Malabsorption Syndromes / Q000097:blood / Q000139:chemically induced*; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000009:adverse effects*; D011485:Protein Binding; D012016:Reference Values; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000139:chemically induced
chemical_list: D009853:Omeprazole; D014805:Vitamin B 12