Non-vitamin K Oral Anticoagulants and Anti-seizure Medications: A Retrospective Cohort Study

Risk of thromboembolic events in patients co-treated with factor Xa-inhibiting direct oral anticoagulants and anti-seizure medications: insights from pharmacovigilance data

BACKGROUND

Limited data have raised concerns about an increased risk of thromboembolic adverse events in atrial fibrillation (AF) patients co-treated with factor Xa-inhibiting direct oral anticoagulants (FXa-DOACs) and anti-seizure medications (ASMs). However, evidence regarding this association remains controversial.

OBJECTIVES

This study aims to investigate the impact of ASMs on the reporting of thromboembolic events in FXa-DOAC-treated patients.

METHODS

This study analyzed data from the FDA Adverse Event Reporting System (FAERS) between 2011Q3 and 2024Q1 using the weighted composite score integrated by four pharmacovigilance signals [reporting odds ratio (ROR), Empirical Bayes Geometric Mean (EBGM), additive model and multiplicative model].

RESULTS

A total of 177 cases of thromboembolic events were identified in patients using combined FXa-DOACs and ASMs. Levetiracetam together with FXa-DOACs was associated with an increased risk of thromboembolic events, particularly apixaban (ROR: 2.29, 95%CI 1.56-3.38; EBGM05:1.32; additive model:0.14 > 0; multiplicative mode: 2.47 > 1;composite score:1) and rivaroxaban (ROR:3.81, 95% CI 2.77-5.26; EBGM05:1.99; additive model:0.13; multiplicative model:1.71; composite score:1). Valproic acid was associated with thromboembolic risk when with rivaroxaban (ROR:4.80, 95%CI 2.50-9.19; EBGM05:1.64; additive model:0.29; multiplicative model:8.48; composite score:1).

CONCLUSION

This study suggests that the concomitant use of levetiracetam and valproic acid with FXa-DOACs is associated with an increased risk of thromboembolic events.

Prescriptions of CYP3A4- and P-gp inducers for patients on direct oral anticoagulants: Bridging the gap between epidemiology and patient management for optimal thromboembolic event prevention

Direct oral anticoagulants (DOACs) are frequently used for the treatment and prevention of ischaemic stroke in patients with non-valvular atrial fibrillation. Compared to vitamin K antagonists, DOACs have significant advantages, although their drug-drug interaction (DDI) profile may complicate drug efficacy and safety. This narrative review addresses the clinical challenges posed by these DDIs and the potential pharmacological alternatives and monitoring strategies available. A PubMed search was conducted (1 January 2000-31 December 2023) including human DDI studies on DOAC use and CYP3A4/P-gp inducers in adult patients, evaluating patient outcome data and recommendations for DDI management. Twenty-two studies were included. Case reports (n = 6) indicated that antiepileptic drugs such as carbamazepine, phenobarbital and phenytoin may be associated with thromboembolic events. The nested case-control studies (n = 2) and cohort studies (n = 9) found that co-administration of DOACs and CYP3A4/P-gp inducers, particularly carbamazepine and phenytoin, increased the risk of thromboembolic events. Pharmacovigilance database analyses indicated a significant association between DOAC DDIs and increased reported stroke rates. Management recommendations in systematic reviews (n = 5) highlighted monitoring when DOACs were combined with inducers. Strategies included using alternative drugs with a weaker or preferentially absent inducing profile. Limited evidence suggests that edoxaban may be an acceptable option in case of DOAC and CYP3A4/P-gp inducer interactions; however, robust clinical data confirming safety are needed. Present literature indicates a higher thromboembolic risk in patients on DOAC treatment combining CYP3A4- and/or P-gp inducers. DOAC management should be tailored to the individual patient through collaboration between expert healthcare professionals.

Fear of the Dark: Concomitant Use of Direct Oral Anticoagulants and Antiseizure Medications

Direct-Acting Oral Anticoagulants and Antiseizure Medications for Atrial Fibrillation and Epilepsy and Risk of Thromboembolic Events Acton EK, Hennessy S, Gelfand MA, Leonard CE, Bilker WB, Shu D, Willis AW, Kasner SE. JAMA Neurol. 2024 Jul 8:e242057. doi: 10.1001/jamaneurol.2024.2057. Epub ahead of print. PMID: 38976246; PMCID: PMC11231911. Importance: Direct-acting oral anticoagulants (DOACs) are commonly prescribed with antiseizure medications (ASMs) due to the concurrency of and the association between atrial fibrillation (AF) and epilepsy. However, enzyme-inducing (EI) ASMs may reduce absorption and accelerate the metabolism of DOACs, potentially lowering DOAC levels and elevating thromboembolism risk. Objective: To assess the rates of thromboembolic and major bleeding events in adults with AF and epilepsy dispensed DOACs and EI ASMs versus DOACs with non-EI ASMs. Design, setting, and participantsDesign, setting, and participants. This active-comparator, new-user cohort study included US healthcare data from the Clinformatics Data Mart database from October 2010 to September 2021 for a nationally representative population of adults with AF and epilepsy. Exposure: Evaluations included episodes of contiguous coadministration of DOACs for AF with EI ASMs (exposed) or non-EI ASMs (referent) for epilepsy. Main outcomes and measures: Thromboembolic events (primary outcome) and major bleeding events (secondary outcome) were identified based on a series of validated, diagnosis-based coding algorithms. Data-adaptive, high-dimensional propensity score matching was used to control for observed confounders and proxies for unobserved confounders. Adjusted hazard ratios (AHRs) were estimated using Cox proportional hazards regression models with robust variance estimators to account for clustering within matched pairs. Results: This study included 14 078 episodes (median age, 74 [IQR, 67-81]; 52.4%female) and 14 158 episodes (median age, 74 [IQR, 67-81]; 52.4%female) of incident DOAC and ASM use that met eligibility criteria for assessment of thromboembolic and major bleeding outcomes, respectively. Incidence was 88.5 per 1000 person-years for thromboembolic events and 68.3 per 1000 person-years for bleeding events. Compared with the use of non-EI ASMs, the use of EI ASMs with DOACs was not associated with a difference in risk of thromboembolic events (AHR, 1.10; 95%CI, 0.82-1.46) but was associated with a reduction in risk of major bleeding events (AHR, 0.63; 95%CI, 0.44-0.89). Conclusions and relevance: In this cohort study, EI ASMs were not associated with alteration in DOAC efficacy. Further research is needed on the reduction in bleeding risk associated with EI ASMs, as this may suggest that pharmacokinetic interactions are associated with lowering DOAC levels without negating therapeutic effects.

Safety and efficacy of concomitant treatment with non-vitamin K antagonist oral anticoagulants and antiseizure medications: A propensity score matching cohort study

Research on cerebrovascular events in atrial fibrillation (AF) patients taking non-vitamin K antagonist oral anticoagulants (NOACs) with antiseizure medications (ASMs) is limited, highlighting a significant gap in literature. We assessed thrombotic and hemorrhagic risks in patients on NOACs and ASMs versus those on NOACs or ASMs alone. We analyzed a retrospective cohort from five centers, including AF and epilepsy patients on both medications (n = 188), AF patients on NOACs (n = 298), and epilepsy patients on ASMs (n = 50), with a 3-year follow-up. Propensity score matching adjusted for cardiovascular risk differences. The primary outcomes were ischemic stroke, transient ischemic attack, and major bleeding. Results showed the ASM+NOAC group had a higher risk of primary outcomes compared to the NOAC-only group (5.68% vs. 1.18%, hazard ratio = 5.72, 95% confidence interval = 2.22-14.73), with no events in the ASM-only group. This suggests an increased risk for patients on combined NOAC and ASM therapy, underlining the need for careful drug interaction consideration.

Direct-Acting Oral Anticoagulants and Antiseizure Medications for Atrial Fibrillation and Epilepsy and Risk of Thromboembolic Events

Importance

Direct-acting oral anticoagulants (DOACs) are commonly prescribed with antiseizure medications (ASMs) due to concurrency of and the association between atrial fibrillation (AF) and epilepsy. However, enzyme-inducing (EI) ASMs may reduce absorption and accelerate metabolism of DOACs, potentially lowering DOAC levels and elevating thromboembolism risk.

Objective

To assess the rates of thromboembolic and major bleeding events in adults with AF and epilepsy dispensed DOACs and EI ASMs vs DOACs with non-EI ASMs.

Design, Setting, and Participants

This active-comparator, new-user cohort study included US health care data from the Clinformatics Data Mart database from October 2010 to September 2021 for a nationally representative population of adults with AF and epilepsy.

Exposure

Evaluations included episodes of contiguous coadministration of DOACs for AF with EI ASMs (exposed) or non-EI ASMs (referent) for epilepsy.

Main Outcomes and Measures

Thromboembolic events (primary outcome) and major bleeding events (secondary outcome) were identified based on a series of validated, diagnosis-based coding algorithms. Data-adaptive, high-dimensional propensity score matching was used to control for observed confounders and proxies for unobserved confounders. Adjusted hazard ratios (AHRs) were estimated using Cox proportional hazards regression models with robust variance estimators to account for clustering within matched pairs.

Results

This study included 14 078 episodes (median age, 74 [IQR, 67-81]; 52.4% female) and 14 158 episodes (median age, 74 [IQR, 67-81]; 52.4% female) of incident DOAC and ASM use that met eligibility criteria for assessment of thromboembolic and major bleeding outcomes, respectively. Incidence was 88.5 per 1000 person-years for thromboembolic events and 68.3 per 1000 person-years for bleeding events. Compared with use of non-EI ASMs, use of EI ASMs with DOACs was not associated with a difference in risk of thromboembolic events (AHR, 1.10; 95% CI, 0.82-1.46) but was associated with a reduction in risk of major bleeding events (AHR, 0.63; 95% CI, 0.44-0.89).

Conclusions and Relevance

In this cohort study, EI ASMs were not associated with alteration in DOAC efficacy. Further research is needed on the reduction in bleeding risk associated with EI ASMs, as this may suggest that pharmacokinetic interactions are associated with lowering DOAC levels without negating therapeutic effects.

Interactions between antiepileptic drugs and direct oral anticoagulants for primary and secondary stroke prevention

INTRODUCTION

Direct oral anticoagulants (DOAC) are the guideline-recommended therapy for prevention of stroke in atrial fibrillation (AF) and venous thromboembolism. Since approximately 10% of patients using antiepileptic drugs (AED) also receive DOAC, aim of this review is to summarize data about drug-drug interactions (DDI) of DOAC with AED by using data from PubMed until December 2023.

AREAS COVERED

Of 49 AED, only 16 have been investigated regarding DDI with DOAC by case reports or observational studies. No increased risk for stroke was reported only for topiramate, zonisamide, pregabalin, and gabapentin, whereas for the remaining 12 AED conflicting results regarding the risk for stroke and bleeding were found. Further 16 AED have the potential for pharmacodynamic or pharmacokinetic DDI, but no data regarding DOAC are available. For the remaining 17 AED it is unknown if they have DDI with DOAC.

EXPERT OPINION

Knowledge about pharmacokinetic and pharmacodynamic DDI of AED and DOAC is limited and frequently restricted to in vitro and in vivo findings. Since no data about DDI with DOAC are available for 67% of AED and an increasing number of patients have a combined medication of DOAC and AED, there is an urgent need for research on this topic.

Pilot study on the probability of drug-drug interactions among direct oral anticoagulants (DOACs) and antiseizure medications (ASMs): a clinical perspective

BACKGROUND

There is little and controversial information about changes in plasma concentrations (PCs) or clinical events during coadministration of antiseizure medications (ASMs) and direct oral anticoagulants (DOACs). We aimed to explore possible determinants of dosage class among DOACs trough PCs when ASMs are co-administered and the relative risks. We also provided some clinical examples of patients' management.

METHODS

Data on adult patients concomitantly treated with ASMs (grouped in enzyme-inducing [I-ASMs], non-inducing [nI-ASMs], and levetiracetam [LEV]) and DOACs with at least one measurement of DOACs' PC were retrospectively collected. The role of DOAC-ASM combinations in predicting PC class (ranging from I at ischemic/thromboembolic risk to IV at increased bleeding risk) was investigated by an ordered logit model, and the marginal probabilities of belonging to the four dosage classes were calculated.

RESULTS

We collected 46 DOACs' PCs out of 31 patients. There were 5 (10.9%) determinations in class I (4 out of 5 with concomitant I-ASMs) and 5 (10.9%) in class IV. The rivaroxaban/I-ASM combination was associated with lower DOAC dosages than rivaroxaban/LEV (OR: 0.00; 95% CI: 0.00-0.62). Furthermore, patient's probability of being in class I was approximately 50% with the rivaroxaban/I-ASM combination, while apixaban, dabigatran, and edoxaban had the highest cumulative probability of being in class II or III despite the ASM used.

CONCLUSION

These preliminary results confirm the reduction of DOAC's PC by I-ASMs and suggest a better manageability of apixaban, dabigatran, and edoxaban independently from the concomitant ASM, whereas rivaroxaban seems the most liable to PC alterations with I-ASMs.

Effectiveness and Safety of Different Oral Anticoagulants with P-glycoprotein/ CYP3A4 Inhibitors: A Network Meta-analysis

BACKGROUND

Metabolism of oral anticoagulants (OAC) is affected by P-glycoprotein (P-gp)/ CYP3A4 enzyme. However, the P-gp/CYP3A4 inhibitors are unavoidably used with OACs.

METHODS

Medline, Cochrane, and Embase were systematically searched for randomized controlled trials and cohort studies from inception till 23rd November, 2022 to assess the safety and effectiveness of OACs when concomitantly used with P-gp/CYP3A4 inhibitors. The primary outcomes were major bleeding and gastrointestinal (GI) bleeding. Secondary outcomes were stroke/systemic embolism (SE), all-cause mortality, any bleeding as well as intracranial hemorrhage (ICH). We estimated summary odds ratios (OR) with 95% credible intervals (CI) using pairwise and network meta-analysis with random effects.

RESULTS

A total of 11 studies involving 37,973 patients were included. When concomitantly used with P-pg/ CYP3A4 inhibitors, network meta-analysis indicated that dabigatran, apixaban, and edoxaban were associated with significantly lower risk of major bleeding compared to rivaroxaban, with ORs of 0.56, 0.51 and 0.48, respectively. Rivaroxaban and dabigatran were associated with a significantly increased risk of GI bleeding than warfarin, apixaban and edoxaban. Dabigatran and apixaban were linked with significantly lower risk of any bleeding compared with warfarin (ORs were 0.75 and 0.68, respectively) or rivaroxaban (ORs were 0.67 and 0.60, respectively). Apixaban (OR 0.32) and edoxaban (OR 0.35) were associated with a lower risk of ICH compared with warfarin. There was no difference between any OACs in terms of stroke/SE or all-cause mortality.

CONCLUSION

When concomitantly used with P-gp/CYP3A4 inhibitors, apixaban and edoxaban were associated with a lower risk of bleeding, though no significant difference in effectiveness was observed among all OACs.

The efficacy of direct oral anticoagulants in patients on concomitant treatment with levetiracetam

Guidelines do not support the combination of direct oral anticoagulants (DOACs) and the antiepileptic drug levetiracetam, due to potential relevant P-glycoprotein (P-gp) mediated interaction that might result in decreased DOACs concentrations and increased thromboembolic risk. However, there is no systematic data on the safety of this combination. The aim of this study was to find patients concurrently treated with levetiracetam and DOAC, assess their plasma concentrations of DOAC, and the incidence of thromboembolic events. From our registry of patients on anticoagulation drugs we identified 21 patients concomitantly treated with levetiracetam and DOAC, 19 patients with atrial fibrillation and two patients with venous thromboembolism. Eight patients received dabigatran, 9 apixaban and 4 rivaroxaban. For each subject blood samples were collected for determination of trough DOAC and trough levetiracetam concentrations. The average age was 75 ± 9 years, 84% were males, HAS-BLED score was 1.8 ± 0.8, and in patients with atrial fibrillation CHA₂DS₂-VASc score was 4.6 ± 2.0. The average trough concentration level of levetiracetam was 31.0 ± 34.5 mg/L. Median trough concentrations of DOACs were for dabigatran 72 (range 25-386) ng/mL, for rivaroxaban 47 (range 19-75) ng/mL, and for apixaban 139 (range 36-302) ng/mL. During the observation period of 1388 ± 994 days none of the patients suffered a thromboembolic event. Our results did not demonstrate a reduction in DOACs plasma levels during levetiracetam treatment, suggesting that levetiracetam could not be an important P-gp inducer in humans. DOAC in combination with levetiracetam remained effective therapy to protect against thromboembolic events.

Thromboembolic Risks with Concurrent Direct Oral Anticoagulants and Antiseizure Medications: A Population-Based Analysis

BACKGROUND AND OBJECTIVE

Drug-drug interactions between direct oral anticoagulants (DOAC) and antiseizure medications via the cytochrome P450 (CYP) or the P-glycoprotein (P-gp) systems may lead to under-anticoagulation. The clinical relevance of these interactions is unclear. We aimed to elucidate the risk of thromboembolism with concurrent DOAC and CYP/P-gp modulating antiseizure medications.

METHODS

In this propensity score-weighted population-based retrospective cohort study, we used competing risk regression analyses to determine the risks of ischemic stroke, venous thromboembolism, and death in DOAC recipients taking CYP/P-gp-modulating antiseizure medications (phenytoin, valproate, levetiracetam, carbamazepine, or phenobarbital) versus those taking CYP/P-gp-neutral antiseizure medications (pregabalin, gabapentin, or clobazam). We also performed secondary analyses for the epilepsy and atrial fibrillation subgroups.

RESULTS

Among DOAC users, CYP/P-gp-modulating antiseizure medications were collectively associated with an increased risk of ischemic stroke (adjusted hazard ratio 1.28, 95% confidence interval 1.05-1.57, p = 0.017). In addition, phenytoin (adjusted hazard ratio 1.34, 95% confidence interval 1.07-1.68, p = 0.011) and valproate (adjusted hazard ratio 1.38, 95% confidence interval 1.10-1.74, p = 0.006) were associated with increased mortality. In the epilepsy subgroup, the risk of ischemic stroke and venous thromboembolism did not differ between CYP/P-gp-modulating and CYP/P-gp-neutral antiseizure medications.

CONCLUSIONS

Although CYP/P-gp-modulating antiseizure medications were associated with an increased risk of ischemic stroke when paired with DOAC in the primary analysis, such a phenomenon was not found among patients with epilepsy who took phenytoin, valproate, or levetiracetam with DOAC. Therefore, these antiseizure medication options among patients with epilepsy with concurrent DOAC should not be restricted solely based on their potential drug-drug interactions. Yet, the increased mortality during concurrent use of DOAC with phenytoin or valproate might call for caution.

Relevant pharmacologic interactions in the concurrent management of brain tumor-related epilepsy and venous thromboembolism: a systematic review

INTRODUCTION

Co-administration of direct oral anticoagulants (DOACs) with antiepileptic drugs (AEDs) is increasingly common in brain tumor patients. We therefore performed a systematic review of the current evidence for potential drug interactions between DOACs and AEDs in this patient population.

METHODS

We conducted a systematic review of the literature via PubMed according to PRISMA guidelines (last accessed December 15, 2021). Included were clinical studies and case reports, written in English language and published between 2010 and 2021, that investigated concurrent clinical use of AEDs with DOACs for any indication. Non-English articles, articles not related to our research question, review articles and commentaries were excluded. Full-text articles were evaluated for possible confounding factors and results were summarized using a data table highlighting the key characteristics of each article.

RESULTS

We identified a total of 122 unique articles, of which 27 were deemed relevant to our research question. Of these, 8 articles were clinical studies (n = 295,415 patients) and 19 were case reports (n = 25 patients). Only 3 clinical studies and 2 case reports reported interactions between AEDs and DOACs in patients with active cancer and none reported interactions in patients with brain tumors.

CONCLUSION

We have identified low (class IV) level evidence of potential drug interactions between DOACs and AEDs. Even though there is no current report of interactions in brain tumor patients, neuro-oncology providers should be aware of the emerging evidence regarding drug interactions between DOACs and AEDs and take this into consideration when concurrently prescribing these to patients.

Comparative diagnosis interest of NfL and pNfH in CSF and plasma in a context of FTD-ALS spectrum

OBJECTIVE

The 'Frontotemporal dementia-Amyotrophic lateral sclerosis Spectrum' (FAS) encompasses different phenotypes, including cognitive disorders (frontotemporal dementia, FTD) and/or motor impairments (amyotrophic lateral sclerosis, ALS). The aim of this study was to apprehend the specific uses of neurofilaments light chain (NfL) and phosphorylated neurofilaments heavy chain (pNfH) in a context of FAS.

METHODS

First, NfL and pNfH were measured in 39 paired cerebrospinal fluid (CSF) and plasma samples of FAS and primary psychiatric disorders (PPD) patients, considered as controls. Secondly, additional plasma samples were included to examine a larger cohort of 81 samples composed of symptomatic FAS and PPD patients, presymptomatic and non-carrier relatives individuals. The measures were performed using Simoa technology.

RESULTS

There was a positive correlation between CSF and plasma values for NfL (p < 0.0001) and for pNfH (p = 0.0036). NfL values were higher for all phenotypes of symptomatic FAS patients compared to PPD patients (p = 0.0016 in CSF; p = 0.0003 in plasma). On the contrary, pNfH values were solely increased in FAS patients exhibiting motor impairment. Unlike symptomatic FAS patients, presymptomatic cases had comparable concentrations with non-carrier individuals.

CONCLUSION

NfL, but not pNfH, appeared to be useful in a context of differential diagnosis between FTD and psychiatric patients. Nevertheless, pNfH seem more specific for the diagnosis and follow-up of motor impairments. In each specific indication, measures in CSF and plasma will provide identical interpretations.