title: Cyclosporine-phenytoin interaction.
abstract: Cyclosporine (CsA), an immunosuppressant, is used widely to prevent rejection of transplanted organs. It is extensively metabolized in the liver by hydroxylation and demethylation. Since phenytoin is used extensively post-transplant as an anti-convulsant, we studied the effect of chronic treatment with phenytoin on CsA by determining the disposition of CsA, prior to and after chronic treatment with phenytoin (30 mg/kg, po) for 5 days. CsA was analyzed by HPLC. The clearance (CL) of CsA was significantly enhanced following treatment with phenytoin when compared to the CL values obtained pretreatment (15.46 +/- 0.76 vs. 25.3 +/- 3.11 ml/min/kg). There were no significant changes in the volume of distribution of CsA. From the above data, we conclude that phenytoin probably induces the metabolism of CsA.
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003524:Cyclosporins / Q000097:blood / Q000493:pharmacokinetics*; D004347:Drug Interactions; D006207:Half-Life; D066298:In Vitro Techniques; D007275:Injections, Intravenous; D008297:Male; D010672:Phenytoin / Q000494:pharmacology*; D011817:Rabbits
chemical_list: D003524:Cyclosporins; D010672:Phenytoin