General ClinicalPharmacokineticsReview 2Universityof FloridaWorkingProfessionalDoctorof PharmacyProgramChristineCrain,Pharm.D.,BCPS
General Clinical Pharmacokinetics Review 2 University of Florida Working Professional Doctor of Pharmacy Program Christine Crain,Pharm.D., BCPS
ClinicalOuestion?A60yearold woman is taking quinidine fortreatment of atrialfibrillation. She has alsobeenprescribedfluconazolefortreatmentoa Candida UTland cisaprideto contro/sxOfGERD.Would you expect any of these drugs tointeractbasedonthehepaticenzymesbywhichtheyare metabolized?
Clinical Question? A 60 year old woman is taking quinidine for treatment of atrial fibrillation. She has also been prescribed fluconazole for treatment of a Candida UTI and cisapride to control sx of GERD. Would you expect any of these drugs to interact based on the hepatic enzymes by which they are metabolized?
Answer to Clinical OuestionHepaticEnzyme(s)AffectedQuinidineInhibits2D6Metabolizedby3A4FluconazolePotentialinhibitorof3A4CisaprideMetabolizedby3A4
Answer to Clinical Question Hepatic Enzyme(s) Affected Quinidine Inhibits 2D6 Metabolized by 3A4 Fluconazole Potential inhibitor of 3A4 Cisapride Metabolized by 3A4
DrugEliminationLiver-PrimarilyMetabolismKidney-PrimarilyExcretion
Drug Elimination Liver - Primarily Metabolism Kidney - Primarily Excretion
Hepatic ClearanceThe efficiency of the liver in removingdrugfromthebloodstreamis referredto as the extraction ratio (E)Withhighextractiondrugs,Eiscloserto 1Withlowextractiondrugs,Eiscloserto 0
Hepatic Clearance The efficiency of the liver in removing drug from the bloodstream is referred to as the extraction ratio (E). With high extraction drugs, E is closer to 1 With low extraction drugs, E is closer to 0