Effect of aprepitant on the pharmacokinetics and pharmacodynamics of warfarin

Abstract

These data are consistent with a significant induction of CYP2C9 metabolism of S(-) warfarin by aprepitant. Subsequently, in patients on chronic warfarin therapy, the clotting status should be monitored closely during the 2-week period, particularly at 7-10 days, following initiation of the 3-day regimen of aprepitant with each chemotherapy cycle.

Study on warfarin plasma concentration and its correlation with international normalized ratio

“…The dose response relationship of warfarin differs between healthy subjects and can vary to a much greater extent among sick patients [3]. It can be influenced by many factors such as pharmacokinetic factors (due to differences in absorption or metabolic clearance of warfarin induced by drug interaction or patient base situation such as gender), pharmacodynamic factors (due to differences in the hemostatic response to given concentrations of warfarin) and technical factors including inaccuracies in laboratory testing and reporting, poor patient compliance, and poor communication between patient and physician [4][5][6]. Drug can influence the pharmacokinetics of warfarin by reducing its absorption from the intestine or by altering its metabolic clearance [3].…”

Genetic variation at the CYP2C locus and its association with torsemide biotransformation

“…17 Well-established in vivo phenotyping probes for CYP2C9 activity are warfarin and tolbutamide. 4,26,[36][37][38] Tolbutamide will probably not be available as a registered drug in the next years in many countries and warfarin requires more sophisticated enantiospecific analysis to be optimal. 39 Thus, one may think about alternative CYP2C9 phenotyping methods.…”

Assessment of Drug–Drug Interaction between Warfarin and Aprepitant and Its Effects on PT-INR of Patients Receiving Anticancer Chemotherapy

“…1) Aprepitant has been reported to be a moderate inhibitor and inducer of CYP3A4, as well as an inducer of CYP2C9. 2,3) The administration of aprepitant (125 mg) is recommended one hour prior to initiating chemotherapy treatment, followed by doses of 80 mg in the morning of the second and third days.…”

“…Compared to placebo-treated subjects, in healthy subjects stabilized on warfarin and administered a 3-d regimen of aprepitant, S-warfarin concentration and PT-INR were found to decrease, respectively, by 34 and 14% on day 8 after aprepitant administration. 2) It is clinically important to elucidate whether aprepitant causes a reduction of the anticoagulation activity of warfarin in patients receiving anticancer chemotherapy, as well as in healthy subjects. We previously reported two cases in which treatment with aprepitant persistently altered antithrombotic control in patients receiving warfarin.…”