title: Interaction of probenecid with the protein binding of methotrexate.
abstract: The effect of probenecid on the plasma protein binding of methotrexate (MTX) has been examined in vitro. At concentrations greater than or equal to 5 x 10(-4) M, probenecid caused a significant reduction (greater than 30%) in the plasma binding of MTX. It is suggested that in vivo this would lead to a greater dispersion into the tissues and a larger volume of distribution, and may be partly responsible for the longer MTX elimination half-life observed with concurrent administration of probenecid.
mesh_terms: D004347:Drug Interactions; D006207:Half-Life; D006801:Humans; D008727:Methotrexate / Q000378:metabolism*; D011339:Probenecid / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D012709:Serum Albumin / Q000378:metabolism*; D014462:Ultrafiltration
chemical_list: D012709:Serum Albumin; D011339:Probenecid; D008727:Methotrexate