title: Bioequivalence of azathioprine products.
abstract: All azathioprine oral tablets are considered bioequivalent by the Food and Drug Administration based on traditional testing. However, since these tests were conducted, it has been determined that some patients have a deficiency of the enzyme most responsible for the metabolism of 6-mercaptopurine-thiopurine methyltransferase (TPMT). Azathioprine is rapidly converted to 6-mercaptopurine, its active metabolite. So it is possible that differences in TPMT activity may influence the bioequivalence of azathioprine products among individuals, especially those patients deficient in TPMT enzyme activity. However, this possibility has not been evaluated.
authors.affiliation: College of Pharmacy, Washington State University Spokane, Spokane, Washington, USA.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Baker
mesh_terms: D000284:Administration, Oral; D001379:Azathioprine / Q000493:pharmacokinetics* / Q000627:therapeutic use; D006801:Humans; D007166:Immunosuppressive Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy; D008780:Methyltransferases / Q000172:deficiency / Q000378:metabolism; D013810:Therapeutic Equivalency; D016896:Treatment Outcome
chemical_list: D007166:Immunosuppressive Agents; D008780:Methyltransferases; C022745:thiopurine methyltransferase; D001379:Azathioprine