The Pharmacology, Efficacy, and Safety of Rivaroxaban in Renally Impaired Patient Populations

Pharmacokinetics and pharmacodynamics of direct oral anticoagulants

INTRODUCTION

Direct oral anticoagulants (DOACs) have overtaken vitamin K antagonists to become the most widely used method of anticoagulation for most indications. Their stable and predictable pharmacokinetics combined with relatively simple dosing, and the absence of routine monitoring has made them an attractive proposition for healthcare providers. Despite the benefits of DOACs as a class, important differences exist between individual DOAC drugs in respect of their pharmacokinetic and pharmacodynamic profiles with implications for dosing and reversal in cases of major bleeding.

AREAS COVERED

This review summarizes the state of knowledge relating to the pharmacokinetics of dabigatran (factor IIa/thrombin inhibitor) and apixaban, edoxaban and rivaroxaban (factor Xa) inhibitors. We focus on pharmacokinetic differences between the drugs which may have clinically significant implications.

EXPERT OPINION

Patient-centered care necessitates a careful consideration of the pharmacokinetic and pharmacodynamic differences between DOACs, and how these relate to individual patient circumstances. Prescribers should be aware of the potential for pharmacokinetic drug interactions with DOACs which may influence prescribing decisions in patients with multiple comorbidities. In order to give an appropriate dose of DOAC drugs, accurate estimation of renal function using the Cockcroft-Gault formula using actual body weight is necessary. An increasing body of evidence supports the use of DOACs in patients who are obese, and this is becoming more routine in clinical practice.

Adverse Clinical Outcomes and Associated Predictors in Rivaroxaban-Treated Atrial Fibrillation Patients With Renal Impairment

Renal impairment confers worse prognosis in patients with atrial fibrillation (AF) but there is scarce evidence about the influence of direct-acting oral anticoagulants in routine clinical practice. Herein, we compared clinical outcomes between patients with AF with and without renal impairment on rivaroxaban and investigated predictors for clinical outcomes in patients with AF with renal impairment. This was a multicenter study including patients with AF on rivaroxaban for at least 6 months. During 2.5 years follow-up, ischemic strokes (IS)/transient ischemic attacks (TIA)/systemic embolisms (SE)/myocardial infarctions (MI), major bleeding, and major adverse cardiovascular events (MACE) were recorded. Creatinine clearance (CrCl) was estimated using the Cockroft-Gault equation, renal impairment was defined as a CrCl <60 ml/min, and 1,433 patients (34.8% with CrCl <60 ml/min) were included. Patients with CrCl <60 ml/min showed higher event rates for major bleeding (1.87%/year vs 0.62%/year; p = 0.003) and MACE (1.97%/year vs 0.62%/year; p = 0.002) but similar event rates for IS/TIA/SE/MI (0.66%/year vs 0.67%/year; p = 0.955). In patients with renal impairment, CHA2DS2-VASc was associated with higher risk of IS/TIA/SE/MI; HAS-BLED and any dependency level were associated with higher risk of major bleeding; and male gender and heart failure were associated with higher risk of MACE. Antiplatelets were independently associated with increased risk of IS/TIA/SE/MI and MACE. In conclusion, in patients with AF on rivaroxaban, the incidence of IS/TIA/SE/MI did not increase in those with renal impairment, suggesting that rivaroxaban may be an effective option in this subgroup. In patients with AF, male gender, heart failure, dependency, antiplatelets, CHA2DS2-VASc, and HAS-BLED were associated with increased risk of adverse outcomes.

Updated Renal Dosage Recommendations for Rivaroxaban in Patients Experiencing or at Risk of Thromboembolic Disease

Patients with chronic kidney disease are at an increased risk of venous thromboembolism (VTE). The factor Xa inhibitor rivaroxaban has been shown to provide similar efficacy and a lower risk of bleeding compared with vitamin K antagonists for the treatment and prevention of VTE. Rivaroxaban has been studied in patients with varying degrees of renal impairment, and this review summarizes current knowledge supporting its use in patients with severe renal impairment (creatinine clearance [CrCl] of 15 to < 30 mL/min) for the prevention, treatment, or prophylaxis of VTE. Clinical pharmacology studies have demonstrated an increase in rivaroxaban systemic exposure, factor Xa inhibition, and prothrombin time with decreasing renal function. These changes reach a plateau with comparable increases in exposure among individuals with moderate or severe renal impairment and end-stage renal disease. The clinical development program for the treatment and prevention of VTE as well as prophylaxis of deep vein thrombosis (DVT) following orthopedic surgery excluded patients with CrCl < 30 mL/min; however, a limited number of patients with severe renal impairment were enrolled. Efficacy outcomes in these patients with severe renal impairment were not meaningfully different from those of patients with higher levels of renal function. There was also no increase in the incidence of major bleeding with rivaroxaban in patients with CrCl < 30 mL/min. Taken together, these pharmacological and clinical data suggest that in patients with severe renal impairment, the approved dosages of rivaroxaban can be used in the treatment and prevention of VTE and for prophylaxis of DVT after hip or knee replacement surgery.

Non-traumatic extraocular muscle haemorrhage associated with anticoagulation use

We present a case of a unilateral extraocular muscle haematoma in an adult female patient who was compliant with life-long oral anticoagulation for recurrent deep vein thrombosis. The patient presented with symptoms of sudden-onset left-sided headache radiating to the temporal region, which started 2 days prior. No obvious triggering factors were identified. Cranial and ocular examinations were within normal limits. Imaging revealed a haemorrhage related to the lateral rectus muscle of the left eye. Conservative management was employed with abstinence from anticoagulation for 2 weeks and a weaning regime of oral steroids. Under the clinical review of ophthalmology and interval radiological monitoring, symptoms were reduced with reduction of haemorrhage size. Anticoagulation was reinstated after 2 weeks. To our knowledge, this is the first case of a non-traumatic extraocular muscle haematoma to be reported in a patient on anticoagulation.

Population Pharmacokinetics and Hemorrhagic Risk Analysis of Rivaroxaban in Elderly Chinese Patients With Nonvalvular Atrial Fibrillation

Rivaroxaban is a popular direct factor Xa inhibitor used for anticoagulation therapy in patients with nonvalvular atrial fibrillation (NVAF). The aim of this study was to establish a population pharmacokinetic (PPK) model for rivaroxaban in elderly Chinese patients with nonvalvular atrial fibrillation, evaluate precision dosing regimens, and analyze hemorrhagic risk after rivaroxaban treatment. A 1-compartment population PK model with estimated glomerular filtration rate (eGFR), total bilirubin (TBIL), and ABCB1 rs1045642 as major covariates for apparent clearance was developed using the nonlinear mixed-effects model (NONMEM). A Monte Carlo simulation was performed to evaluate various dosing schemes and different levels of covariates for the target range of therapeutic drug-monitoring concentrations (C_max,ss and C_min,ss ). The exposure to rivaroxaban was simulated and assessed through hemorrhagic risk evaluation. The results showed that the average probability of target attainment (PTA) for optimal dosing regimens with different covariate levels for the targeted C_max,ss and C_min,ss were 29.35% to 31.3% and 64.91% to 65.8%, respectively. A dosage of 10 mg of rivaroxaban in elderly Chinese patients with normal renal and liver function was appropriate. The area under the concentration-time curve estimated over 24 hours with precision dosing at steady state (AUC_24,ss ) was statistically significantly associated with an increased risk of bleeding events (OR 1.0006, 95%CI 1.0003 to 1.001, P < .0001), and the bleeding risk increased by 1.82-fold for every 1000 μg*h/L increase in AUC_24,ss . A lower dose is recommended for elderly patients with renal impairment to avoid overexposure and bleeding events. The PPK model could inform individualized dosing for elderly Chinese patients with nonvalvular atrial fibrillation receiving rivaroxaban anticoagulation therapy.

Plasma Rivaroxaban Level in Patients With Early Stages of Chronic Kidney Disease-Relationships With Renal Function and Clinical Events

Introduction Drug accumulation of rivaroxaban is a concern in patients with chronic kidney disease (CKD). Data regarding the plasma rivaroxaban levels in early CKD patients and its relationship with clinical events is lacking. Methods Early CKD patients (Stage 1-3) with atrial fibrillation who received rivaroxaban (15 or 20 mg daily) were recruited. Plasma rivaroxaban levels were measured at 2 hours (peak) and 24 hours (trough) after drug administration, and correlated with eGFR and clinically significant events during the follow-up period (1 January 2018 to 31 October 2021). Results Ninety-two patients were included (CKD stage 1 n=10, stage 2 n=53, stage 3 n=29). Plasma trough levels in patients with stage 3 CKD were significantly higher than those with stage 2 and 1 CKD (66.0±34.9 ng/ml vs. 35.7 ± 24.7 ng/ml vs. 34.7 ± 26.2 ng/ml, respectively, p=0.005), and showed inverse relationship with eGFR (r=0.391, p=0.001) in patients receiving 20 mg daily. The plasma trough rivaroxaban level correlated with PT and APTT (r = 0.650 and 0.44, respectively, p<0.001 for both). Plasma trough rivaroxaban level in those with bleeding were higher than those who did not (59.9 ± 35.6 ng/ml vs. 41.1 ± 29.2 ng/ml, p=0.011), and multivariate analysis suggested that plasma trough rivaroxaban level was associated with the rate of bleeding complications (OR: 1.020, 95% CI 1.002-1.038, p=0.028). Conclusion Plasma trough rivaroxaban levels correlated with renal function in early CKD patients, and its measurement may help dosage optimization in patients with renal impairment. Moreover, our data suggests that there may be an association between plasma trough rivaroxaban level and the rate of bleeding complication.

Real world data of anticoagulant treatment in non-valvular atrial fibrillation across renal function status

The objective is to assess the impact of anticoagulant treatment in non-valvular atrial fibrillation (AF) and different categories of renal dysfunction in real world. Electronic Health recordings of patients with diagnosis of AF and renal function collected throughout 5 years and classified according to KDIGO categories. Stroke, transitory ischemic attack (TIA), intracranial hemorrhage and all-cause mortality were identified. Anticoagulant treatments during the study period were classified in untreated (never received therapy), VKA, NOAC and Aspirin. The risk of events was calculated by Cox-proportional hazard models adjusted by confounders. A total of 65,734 patients with AF, mean age 73.3 ± 10.49 years old and 47% females and follow-up of 3.2 years were included. KDIGO classification were: G1 33,903 (51.6%), G2 17,456 (26.6%), G3 8024 (12.2%) and G4 6351 (9.7%). There were 8592 cases of stroke and TIA, 437 intracranial hemorrhage, and 9603 all-cause deaths (incidence 36, 2 and 38 per 10³ person/year, respectively). 4.1% of patients with CHA2DS2-VASc Score 2 or higher did not receive anticoagulant therapy. Risk of stroke, TIA, and all-cause mortality increased from G1 to G4 groups. Anticoagulant treatments reduced the risk of events in the four categories, but NOAC seemed to offer significantly better protection. Renal dysfunction increases the risk of events in AF and anticoagulant treatments reduced the risk of stroke and all-cause mortality, although NOAC were better than VKA. Efforts should be done to reduce the variability in the use of anticoagulants even in this high risk group.

Developing LC-MS/MS methods to quantify rivaroxabanin human plasma and urine: application to therapeuticdrug monitoring

Rivaroxaban is an oral anticoagulant directly inhibiting Factor Xa activity, which is widely used for prophylaxis of thromboembolic disorders and is required for therapeutic drug monitoring (TDM) during therapyfor individual dosage adjustment. Thisstudyaimed at developing a liquidchromatography/tandem mass spectrometry method that was suitable forrivaroxaban TDM in human plasma and urine and exploring the feasibility of urine drug monitoring in medical care. The 3-min run of LC-MS/MS methodswereestablishedby employingan Acquity UPLC BEH C₁₈ (2.1 mm × 50 mm, 1.7 μm) column using gradient elution of 10 mmol/L ammonium acetate containing 0.1% formic acid - 0.1% formic acid acetonitrile as mobile phase at a flow rate of 0.4 mL/min with the calibration range of 0.5 ng/mL-400 ng/mL and 10 ng/mL-10000 ng/mLfor human plasma and urine, respectively. Rivaroxaban wasdetected on a triple quadrupole tandem mass spectrometer with electrospray ionization source in positive ion mode. Themethods showed good linearity within the calibration range. Theprecision and accuracy, matrix effect, extraction recovery and stability inboth human matrices were all validatedand meet the international guideline requirements. These validated methods had been successfullyapplied to support TDMofan aged patient receiving rivaroxaban for therapy.