Drug-Drug Interactions of Direct Oral Anticoagulants (DOACs): From Pharmacological to Clinical Practice

Screening for clinically relevant drug-drug interactions between direct oral anticoagulants and antineoplastic agents: a pharmacovigilance approach

BACKGROUND

Use of direct oral anticoagulants (DOACs) in patients with cancer remains suboptimal due to the concern regarding potential drug-drug interactions (DDIs) with antineoplastic treatments. However, the clinical relevance of these DDIs is unknown.

METHODS

We conducted a pharmacovigilance study of adverse event (AE) reports from the US Food and Drug Administration Adverse Event Reporting System from 1/1/2004 to 12/31/2021. AE reports containing DOACs and antineoplastic agents with CYP3A4/P-gp inhibitory or inducing activity suggested by published pharmacokinetic studies were included (n = 36,066). The outcomes of interest were bleeding or stroke, identified by MedDRA dictionary version 25.0. We used disproportionality analyses (DPA), logistic regression models (LR), and Multi-item Gamma-Poisson Shrinker (MGPS) (Empirical Bayes Geometric Means (EBGM) and 90% credible intervals (90% CIs)) algorithms to identify the safety signal of DDIs.

RESULTS

The highest bleeding reporting rates for each drug class were the combination of DOACs with neratinib (39.08%, n = 34), tamoxifen (21.22%, n = 104), irinotecan (20.54%, n = 83), and cyclosporine (19.17%, n = 227). The highest rate of stroke was found for prednisolone (2.43%, n = 113). In the primary analysis, no signal of DDIs by the antineoplastic therapeutic class was detected by MGPS, DPA, and LR approaches. By individual antineoplastic drug, DOACs-neratinib was the only signal detected [EBGM (EB05-EB95) = 2.71 (2.03-3.54)].

CONCLUSION

No signal of DDIs between DOACs and antineoplastic agents was detected, except for DOAC-neratinib. Most DDIs between DOACs and antineoplastic agents may not be clinically relevant. The DDIs between DOACs and neratinib should be further examined in future research.

Cancer-associated thrombosis and drug-drug interactions of antithrombotic and antineoplastic agents

Venous thromboembolism (VTE) is often associated with malignant diseases and notably contributes to morbidity and mortality in patients with cancer. Cancer-associated thrombosis (CAT) brings additional costs to health expenditures and has a negative impact on oncological outcomes. Either the recurrence rate of VTE or bleeding complications are also higher in patients with cancer. Prophylactic anticoagulation has been recommended in peri-surgical periods, inpatient settings, and high-risk ambulatory patients. Although various risk stratification scores are used, none are ideal for identifying patients who can benefit from anticoagulant prophylaxis. New risk scoring systems or biomarkers are needed to identify patients who are more likely to benefit from prophylaxis with low bleeding risk. The questions about the patients who will be given prophylaxis and those who develop thromboembolism, with which drug, and how long they will be treated are still not fully answered. Anticoagulation is the cornerstone of the treatment, but management of CAT remains complex. Low molecular weight heparins and direct oral anticoagulants are effective and safe options for the treatment of CAT. Recognizing adverse effects, drug-drug interactions, and accompanying conditions that cause dose adjustment is crucial. Prevention and treatment of VTE in patients with cancer require a multidisciplinary and patient-based approach. PLAIN LANGUAGE SUMMARY: Cancer-associated thrombosis is a significant cause of mortality and morbidity in patients with cancer. Chemotherapy, surgery, and/or use of central venous access remarkably increase the risk of thrombosis. Prophylactic anticoagulation should be considered not only in inpatient follow-up and during peri-surgical period but also ambulatory patients with a high risk of thrombosis. Many parameters, such as drug-drug interactions, primary side of cancer, and comorbidities of patients should be considered when selecting anticoagulant drugs. More accurate risk stratification scores or biomarkers are still an unmet need.

Optimizing Pharmacotherapy for Direct Oral Anticoagulants in Older Adults: Strategies for Managing Drug Interactions

Direct oral anticoagulants (DOACs) have been increasingly used by older adults. Although these medications offer several therapeutic advantages over traditional anticoagulants, such as warfarin, they have limitations. One significant concern associated with DOACs is their potential for drug-drug interactions. These interactions may compromise the safe and effective use of DOACs and can potentially lead to serious adverse events and complications, particularly major bleeding. Polypharmacy is common among older adults with chronic diseases, which can increase the risk of drug-drug interactions with DOACs. The current article discusses the impact and risks of drug-drug interactions with DOACs in the context of older adults and explores ways to improve and manage these interactions through the collaboration of an interprofessional team. [Journal of Gerontological Nursing, 49(9), 7-13.].

Assessment of bleeding risk in cancer patients treated with anticoagulants for venous thromboembolic events

Introduction

Anticoagulant is the cornerstone of the management of VTE at the cost of a non-negligible risk of bleeding. Reliable and validated clinical tools to predict thromboembolic and hemorrhagic events are crucial for individualized decision-making for the type and duration of anticoagulant treatment. We evaluate the available risk models in real life cancer patients with VTE. The objectives of the study were to describe the bleeding of cancer patients with VTE and to evaluate the performance of the different bleeding models to predict the risk of bleeding during a 6-month follow-up.

Materials and Methods

VTE-diagnosed patient's demographic and clinical characteristics, treatment regimens and outcomes for up to 6 months were collected. The primary endpoint was the occurrence of a major bleeding (MB) or a clinically relevant non major bleeding (CRNMB) event, categorized according to the ISTH criteria.

Results

During the 6-months follow-up period, 26 out of 110 included patients (26.7%) experienced a bleeding event, with 3 recurrences of bleeding. Out of the 29 bleeding events, 19 events were CRNMB and 10 MB. One patient died because of a MB. Bleeding occurred in 27 % of the patients treated with DOACs and 22% of the patients treated with LMWH. Most of the bleedings were gastrointestinal (9 events, 31%); 26.9% of the bleedings occurred in patient with colorectal cancer and 19.6% in patients with lung cancer. In our cohort, none of the 10 RAMs used in our study were able to distinguish cancer patients with a low risk of bleeding, from all bleeding or non-bleeding patients. The Nieto et al. RAM had the best overall performance (C-statistic = 0.730, 95% CI (0.619-0.840)). However, it classified 1 out of 5 patients with major bleeding in the low risk of bleeding group. The rest of the RAMs showed a suboptimal result, with a range of C-statistic between 0.489, 95%CI (0.360-0.617)) and 0.532, 95%CI (0.406-0.658)).

Conclusions

The management of CAT patients is challenging due to a higher risk of both recurrent VTE and bleeding events, as compared with non-cancer patients with VTE. None of the existing RAMs was able to consistently identify patients with risk of anticoagulant associated bleeding events.

Physiologically-based pharmacokinetic pharmacodynamic parent-metabolite model of edoxaban to predict drug-drug-disease interactions: M4 contribution

This study aimed to develop a physiologically-based pharmacokinetic pharmacodynamic (PBPK/PD) parent-metabolite model of edoxaban, an oral anticoagulant with a narrow therapeutic index, and to predict pharmacokinetic (PK)/PD profiles and potential drug-drug-disease interactions (DDDIs) in patients with renal impairment. A whole-body PBPK model with a linear additive PD model of edoxaban and its active metabolite M4 was developed and validated in SimCYP for healthy adults with or without interacting drugs. The model was extrapolated to situations including renal impairment and drug-drug interactions (DDIs). Observed PK and PD data in adults were compared with predicted data. The effect of several model parameters on the PK/PD response of edoxaban and M4 was investigated in sensitivity analysis. The PBPK/PD model successfully predicted PK profiles of edoxaban and M4 as well as anticoagulation PD responses with or without the influence of interacting drugs. For patients with renal impairment, the PBPK model successfully predicted the fold change in each impairment group. Inhibitory DDI and renal impairment had a synergistic effect on the increased exposure of edoxaban and M4, and their downstream anticoagulation PD effect. Sensitivity analysis and DDDI simulation show that renal clearance, intestinal P-glycoprotein activity, and hepatic OATP1B1 activity are the major factors affecting edoxaban-M4 PK profiles and PD responses. Anticoagulation effect induced by M4 cannot be ignored when OATP1B1 is inhibited or downregulated. Our study provides a reasonable approach to adjust the dose of edoxaban in several complicated scenarios especially when M4 cannot be ignored due to decreased OATP1B1 activity.

Stability of Direct Oral Anticoagulants Concentrations in Blood Samples for Accessibility Expansion of Chromogenic Assays

Background and Objectives: Direct oral anticoagulants (DOACs) are used for minimising the risk of thromboembolic events. In clinical practice, there is no need to measure DOAC concentration in the routine. Nevertheless, there are cases where such measurements are necessary, as the European Society of Cardiology's guideline recommends. However, determining DOAC levels is not available for everyone due to chromogenic assay availability limitations from sample storage problems, as tests are performed only in a few healthcare settings. This study aimed to assess whether more applicable storage conditions could be used for transportation to provide chromogenic assays for outpatient healthcare and other hospitals' practices. Materials and Methods: Chromogenic assays measuring anti-FXa (for rivaroxaban and edoxaban) and anti-FIIa (for dabigatran) were used. Concentrations were determined immediately after blood collection as baseline value: (1) after the storage of citrated whole blood in refrigerator (+2-8 °C); (2) of citrated plasma in refrigerator (+2-8 °C); and (3) of citrated frozen plasma (-20 °C) on the third and seventh days of storage. Acceptable change limits were considered stable if the deviation did not exceed ±20% of the baseline value. Results: The median (Cl 95%) baseline value of rivaroxaban was 168 (147-236) ng/mL; of dabigatran 139 (99-178) ng/mL; and of edoxaban-174 (135-259) ng/mL. The median deviation from a baseline value stored as citrate whole blood samples (+2-8 °C) was 5.4% and 3.4%; as citrated plasma (+2-8 °C) was 0.4% and -0.6%; and as citrated frozen plasma (-20 °C) was -0.2% and 0.2% on the third and seventh days of storage, respectively. Conclusions: Our data suggest that whole blood samples stored in a refrigerator, as well as citrated plasma samples stored in both the refrigerator and freezer, preserve DOAC concentration stable at +2-8 °C or -20 °C for up to 7 days, and are suitable for transportation, except for low-concentration samples.

Direct oral anticoagulant drugs for the management of venous thromboembolism

ABSTRACT

Direct oral anticoagulants (DOACs) are effective for both prevention and treatment of venous thromboembolism (VTE) and have favorable safety in comparison with warfarin. Although drug-drug interactions with DOACs are not as frequent as with warfarin, certain drugs can interfere with DOAC metabolism, affect DOAC efficacy, and potentially cause adverse reactions when used in combination with DOACs. The NP must determine which agent is most beneficial for the individual patient with VTE based on a number of factors. A knowledge of periprocedural management of DOACs will assist the NP in providing a smooth transition for patients undergoing minor and major procedures and surgeries.

Direct-Acting Oral Anticoagulant Therapy in Cancer Patients-A Review

Venous thromboembolism (VTE) is an important aspect in cancer patients. There are various pharmacological methods used for thrombotic event treatment. DOACs (direct-acting oral anticoagulants) are gaining popularity among both physicians and researchers and are slowly starting to replace VKAs (vitamin K antagonists), thus becoming a substitute or alternative option for LMWHs (low-molecular-weight heparins). In this article, we present DOACs' main therapeutic advantages and disadvantages in patients with cancer. The only major concern with using DOACs is the higher risk of bleeding; however, there are discrepancies in this matter. There are still some types of cancer for which DOACs are not recommended. Specific cancer types may influence the efficacy of DOAC therapy. Additionally, race and ethnicity may affect therapy in cancer patients with DOACs. A sizeable number of clinical trials are focused on comparing DOACs with other anticoagulants. The current guidelines of different scientific associations are not unanimous in their DOAC assessments. There is still a need for more evidence of DOACs' potential advantages over other methods of anticoagulation in cancer patients to facilitate their position in this recommendation. This literature review presents the current state of knowledge about the use of DOACs in patients with neoplastic growth.

Risk Factors for Rivaroxaban-Related Bleeding Events-Possible Role of Pharmacogenetics: Case Series

Non-vitamin K antagonist oral anticoagulants' interindividual trough concentration variability affects efficacy and safety, especially in bleeding events. Rivaroxaban is metabolised via CYP3A4/5-, CYP2J2-, and CYP-independent mechanisms and is a substrate of two transporter proteins: ABCB1 (MDR1, P-glycoprotein) and ABCG2 (BCRP; breast-cancer-resistance protein). The polymorphisms of these genes may possibly affect the pharmacokinetics of rivaroxaban and, consequently, its safety profile. Rivaroxaban variability may be associated with age, liver and kidney function, concomitant illness and therapy, and pharmacogenetic predisposition. This case series is the first, to our knowledge, that presents multiple risk factors for rivaroxaban-related bleeding (RRB) including age, renal function, concomitant diseases, concomitant treatment, and pharmacogenetic data. It presents patients with RRB, along with their complete clinical and pharmacogenetic data, as well as an evaluation of possible risk factors for RRB. Thirteen patients were carriers of ABCB1, ABCG2, CYP2J2, and/or CYP3A4/5 gene polymorphisms. Possible drug-drug interactions with increased bleeding risk were identified in nine patients. Six patients had eGFR <60 mL/min/1.73 m2. Our data suggest a possible role of multiple factors and their interactions in predicting RRB; however, they also indicate the need for further comprehensive multidisciplinary research to enable safer use of this product based on a personalised approach.

A Real-World Matched Cohort Study of the Effect of Concomitant Amiodarone or Diltiazem Administration on Apixaban Peak and Trough Concentrations

BACKGROUND

Apixaban is a substrate for p-glycoprotein and is extensively metabolized by cytochrome P450 (CYP) 3A4. There are minimal published data regarding the effect of amiodarone and diltiazem on apixaban serum concentrations.

OBJECTIVE

The aim of this study was to determine the degree of elevation of apixaban concentrations resulting from amiodarone or diltiazem.

METHODS

This was a matched cohort study approved by the Institutional Review Board. Patients receiving apixaban 5 mg twice daily with concomitant diltiazem or amiodarone were enrolled. Control groups were enrolled via matching characteristics of sex, age, weight, creatinine clearance, and statin therapy. Exclusions were an inappropriate dosage of apixaban or concomitant dronedarone, verapamil, ranolazine, naproxen, or both amiodarone and diltiazem. Blood samples were collected 3-4 h after and 0.5-2 h before an apixaban dose, corresponding to peak and trough concentrations, respectively. Results were compared using a t test.

RESULTS

Thirty patients were enrolled in each of the four groups. The mean peak apixaban concentration was 239 ± 82 ng/mL in the amiodarone group and 208 ± 66 ng/mL in the corresponding control group (p = 0.068). Trough concentrations were 142 ± 71 ng/mL and 117 ± 41 ng/mL, respectively (p = 0.055). The mean peak apixaban concentration was 243 ± 99 ng/mL in the diltiazem group and 213 ± 82 ng/mL in the control group (p = 0.11). Trough concentrations were 130 ± 65 ng/mL and 108 ± 54 ng/mL, respectively (p = 0.09).

CONCLUSION

Coadministration of amiodarone and diltiazem resulted in a trend toward increased apixaban concentrations. The extent of elevation suggests that empiric dose changes are not necessary; however, individual patients may benefit from monitoring and dose adjustment.

Individual Pharmacotherapy Management (IPM)—IV: Optimized Usage of Approved Antimicrobials Addressing Under-Recognized Adverse Drug Reactions and Drug-Drug Interactions in Polypharmacy

Antimicrobial therapy is often a life-saving medical intervention for inpatients and outpatients. Almost all medical disciplines are involved in this therapeutic procedure. Knowledge of adverse drug reactions (ADRs) and drug-drug interactions (DDIs) is important to avoid drug-related harm. Within the broad spectrum of antibiotic and antifungal therapy, most typical ADRs are known to physicians. The aim of this study was to evaluate relevant pharmacological aspects with which we are not so familiar and to provide further practical guidance. Individual pharmacotherapy management (IPM) as a synopsis of internal medicine and clinical pharmacology based on the entirety of the digital patient information with reference to drug information, guidelines, and literature research has been continuously performed for over 8 years in interdisciplinary intensive care and trauma and transplant patients. Findings from over 52,000 detailed medication analyses highlight critical ADRs and DDIs, especially in these vulnerable patients with polypharmacy. We present the most relevant ADRs and DDIs in antibiotic and antifungal pharmacology, which are less frequently considered in relation to neurologic, hemostaseologic, hematologic, endocrinologic, and cardiac complexities. Constant awareness and preventive strategies help avoid life-threatening manifestations of these inherent risks and ensure patient and drug safety in antimicrobial therapy.

Superiority of Direct Oral Anticoagulants over Vitamin K Antagonists in Oncological Patients with Atrial Fibrillation: Analysis of Efficacy and Safety Outcomes

Background and aim. Cancer and atrial fibrillation (AF) may be associated, and anticoagulation, either with vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs), is necessary to prevent thromboembolic events by reducing the risk of bleeding. The log incidence rate ratio (IRR) and 95% confidence interval were used as index statistics. Higgin’s I2 test was adopted to assess statistical inconsistencies by considering interstudy variations, defined by values ranging from 0 to 100%. I2 values of less than 40% are associated with very low heterogeneity among the studies; values between 40% and 75% indicate moderate heterogeneity, and those greater than 75% suggest severe heterogeneity. The aim of this meta-analysis was to compare the safety and efficacy of VKAs and DOACs in oncologic patients with AF. Methods. A meta-analysis was conducted comparing VKAs to DOACs in terms of thromboembolic events and bleeding. A meta-regression was conducted to investigate the differences in efficacy and safety between four different DOACs. Moreover, a sub-analysis on active-cancer-only patients was conducted. Results. A total of eight papers were included. The log incidence rate ratio (IRR) for thromboembolic events between the two groups was −0.69 (p < 0.005). The meta-regression did not reveal significant differences between the types of DOACs (p > 0.9). The Log IRR was −0.38 (p = 0.008) for ischemic stroke, −0.43 (p = 0.02) for myocardial infarction, −0.39 (p = 0.45) for arterial embolism, and −1.04 (p = 0.003) for venous thromboembolism. The log IRR for bleeding events was −0.43 (p < 0.005), and the meta-regression revealed no statistical difference (p = 0.7). The log IRR of hemorrhagic stroke, major bleeding, and clinically relevant non-major bleeding between the VKA and DOAC groups was −0.51 (p < 0.0001), −0.45 (p = 0.03), and 0.0045 (p = 0.97), respectively. Similar results were found in active-cancer patients for all the endpoints except for clinically-relevant non-major bleedings. Conclusions. DOACs showed better efficacy and safety outcomes than VKAs. No difference was found between types of DOACs.

Dilemmas in the Choice of Adequate Therapeutic Treatment in Patients with Acute Pulmonary Embolism—From Modern Recommendations to Clinical Application

Pulmonary thromboembolism is a very common cardiovascular disease, with a high mortality rate. Despite the clear guidelines, this disease still represents a great challenge both in diagnosis and treatment. The heterogeneous clinical picture, often without pathognomonic signs and symptoms, represents a huge differential diagnostic problem even for experienced doctors. The decisions surrounding this therapeutic regimen also represent a major dilemma in the group of patients who are hemodynamically stable at initial presentation and have signs of right ventricular (RV) dysfunction proven by echocardiography and positive biomarker values (pulmonary embolism of intermediate–high risk). Studies have shown conflicting results about the benefit of using fibrinolytic therapy in this group of patients until hemodynamic decompensation, due to the risk of major bleeding. The latest recommendations give preference to new oral anticoagulants (NOACs) compared to vitamin K antagonists (VKA), except for certain categories of patients (patients with antiphospholipid syndrome, mechanical valves, pregnancy). When using oral anticoagulant therapy, special attention should be paid to drug–drug interactions, which can lead to many complications, even to the death of the patient. Special population groups such as pregnant women, obese patients, patients with antiphospholipid syndrome and the incidence of cancer represent a great therapeutic challenge in the application of anticoagulant therapy. In these patients, not only must the effectiveness of the drugs be taken into account, but great attention must be paid to their safety and possible side effects, which is why a multidisciplinary approach is emphasized in order to provide the best therapeutic option.