Novel drugs for oral anticoagulation pharmacotherapy

Prediction of Rivaroxaban-Rifampin Interaction After Major Orthopedic Surgery: Physiologically Based Pharmacokinetic Modeling and Simulation

Rivaroxaban is commonly used for the prophylaxis of venous thromboembolism (VTE) for patients undergoing major orthopedic surgery. Rivaroxaban is primarily eliminated by hepatic CYP450 metabolism and renal excretion. Rifampin is a commonly used antibiotic for prosthetic joint infections (PJI) and a potent inducer of CYP450 enzymes. Clinical data about drug-drug interactions of rivaroxaban and rifampin are limited. The present study is to describe DDI of rivaroxaban and rifampin in several prosthetic joint infections patients undergoing major orthopedic surgery. We retrospectively identified six patients concomitantly administered with rivaroxaban and rifampin between 2019 and 2020. Plasma samples of these patients with accurate sampling time were chosen from the biobank and plasma levels of rivaroxaban were measured at each time point. A physiologically based pharmacokinetic model for the rivaroxaban-rifampin interaction was developed to predict the optimal dosing regimen of rivaroxaban in the case of co-medication with rifampin. The model was validated by the observed plasma concentration of rivaroxaban from the above patients. From this model, it could be simulated that when rifampin starts or stops, gradually changing rivaroxaban dose during the first few days would elevate the efficacy and safety of rivaroxaban.

Application of physiologically based pharmacokinetic modeling to the prediction of drug-drug and drug-disease interactions for rivaroxaban

PURPOSE

Rivaroxaban is a direct oral anticoagulant with a large inter-individual variability. The present study is to develop a physiologically based pharmacokinetic (PBPK) model to predict several scenarios in clinical practice.

METHODS

A whole-body PBPK model for rivaroxaban, which is metabolized by the cytochrome P450 (CYP) 3A4/5, 2J2 pathways and excreted via kidneys, was developed to predict the pharmacokinetics at different doses in healthy subjects and patients with hepatic or renal dysfunction. Hepatic clearance and drug-drug interactions (DDI) were estimated by in vitro in vivo extrapolation (IVIVE) based on parameters obtained from in vitro experiments. To validate the model, observed concentrations were compared with predicted concentrations, and the impact of special scenarios was investigated.

RESULTS

The PBPK model successfully predicted the pharmacokinetics for healthy subjects and patients as well as DDIs. Sensitivity analysis shows that age, renal, and hepatic clearance are important factors affecting rivaroxaban pharmacokinetics. The predicted fold increase of rivaroxaban AUC values when combined administered with the inhibitors such as ketoconazole, ritonavir, and clarithromycin were 2.3, 2.2, and 1.3, respectively. When DDIs and hepatic dysfunction coexist, the fold increase of rivaroxaban exposure would increase significantly compared with one factor alone.

CONCLUSIONS

Our study using PBPK modeling provided a reasonable approach to evaluate exposure levels in special patients under special scenarios. Although further clinical study or real-life experience would certainly merit the current work, the modeling work so far would at least suggest caution of using rivaroxaban in complicated clinical settings.

Antithrombotic therapy for secondary prevention of atherothrombotic events in cerebrovascular disease

Atherothrombosis is the common underlying process for numerous progressive manifestations of cardiovascular disease, including coronary artery disease (CAD) and cerebrovascular disease (CVD). Antiplatelet therapy is the cornerstone of pharmacological management in patients with atherothrombosis. Over the past 20 years, major advances in antiplatelet pharmacotherapy have been made, particularly for the treatment of patients with CAD. The treatment of patients with concomitant CAD and CVD is complex, owing to their increased risk of both ischaemia and bleeding. When CVD arises from large artery atherosclerosis, antithrombotic therapies are essential to prevent stroke or transient ischaemic attack (TIA). However, the use of antithrombotic medications in patients with CVD can put them at high risk of intracranial haemorrhage. As such, the risk-benefit profile of various combinations of antiplatelet agents in patients with both CAD and CVD is uncertain. This Review provides a state-of-the-art account of the available evidence on antithrombotic therapies for the secondary prevention of atherothrombotic events in patients with concomitant CAD and CVD, particularly those with a history of noncardioembolic stroke or TIA.

Antithrombotic therapy for secondary prevention of atherothrombotic events in cerebrovascular disease

Atherothrombosis is the common underlying process for numerous progressive manifestations of cardiovascular disease, including coronary artery disease (CAD) and cerebrovascular disease (CVD). Antiplatelet therapy is the cornerstone of pharmacological management in patients with atherothrombosis. Over the past 20 years, major advances in antiplatelet pharmacotherapy have been made, particularly for the treatment of patients with CAD. The treatment of patients with concomitant CAD and CVD is complex, owing to their increased risk of both ischaemia and bleeding. When CVD arises from large artery atherosclerosis, antithrombotic therapies are essential to prevent stroke or transient ischaemic attack (TIA). However, the use of antithrombotic medications in patients with CVD can put them at high risk of intracranial haemorrhage. As such, the risk-benefit profile of various combinations of antiplatelet agents in patients with both CAD and CVD is uncertain. This Review provides a state-of-the-art account of the available evidence on antithrombotic therapies for the secondary prevention of atherothrombotic events in patients with concomitant CAD and CVD, particularly those with a history of noncardioembolic stroke or TIA.