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.

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.

Update on drug interactions with non-vitamin-K-antagonist oral anticoagulants for stroke prevention in elderly patients

Introduction: We update the knowledge, since the last review in 2017, about drug-drug interactions (DDI) of non-vitamin-K-antagonist oral anticoagulants (NOAC) in patients ≥75 years.Areas covered: The literature was searched for: 'dabigatran,' 'rivaroxaban,' 'edoxaban,' or 'apixaban' and drugs, affecting platelet function, CYP3A4-, CYP2C9-, or P-Gp-activity. Pharmacodynamic DDI of NOAC with drugs affecting platelet function like nonsteroidal anti-inflammatory drugs and antiplatelet agents occur most frequently. Pharmacokinetic DDI with NOAC were found for 37 of 117 drugs. Reports about DDI with NOAC were found for 51% of P-gp-affecting, 38% for CYP2C9-affecting and 27% for CYP3A4-affecting drugs. Reports about DDI of cardiovascular drugs with NOAC were the most prevalent, followed by anti-infective and nervous system drugs. NOAC plasma levels were measured in retrospective and cohort studies and were associated with concomitant medication. Reports about DDI of NOAC were found in 71 patients ≥75 years.Expert opinion: The knowledge about DDI of NOAC in elderly patients is very limited. Studies should be carried out to investigate the role of drugs potentially interacting with NOAC, which until now have not been investigated. When studying DDI of NOAC, care should be taken to include elderly patients with impaired renal function and patients on polymedication.

Drug-drug interactions with direct oral anticoagulants associated with adverse events in the real world: A systematic review

BACKGROUND

Direct oral anticoagulants (DOACs) have emerged as safe and effective alternatives to Vitamin-K antagonists for treatment and prevention of arterial and venous thrombosis. Due to their novelty, pharmacokinetic DOAC drug-drug interactions (DDIs) that result in clinical adverse events have not been well-documented.

OBJECTIVE

This study aims to systematically review reported pharmacokinetic DDIs resulting in clinical adverse events through documented observational evidence to better inform clinicians in clinical practice.

METHODS

A comprehensive literature review of EMBASE, MEDLINE, and Ovid HealthStar was conducted through March 10th, 2020. Two independent reviewers screened and extracted data from eligible articles according to pre-established inclusion and exclusion criteria. Articles reporting bleeding or thrombotic outcomes in non-controlled (observational) settings resulting from suggested pharmacokinetic DOAC DDIs were included.

RESULTS

A total of 5567 citations were reviewed, of which 24 were included following data extraction. The majority were case reports (n = 21) documenting a single adverse event resulting from a suspected DOAC DDI, while the remaining papers were a case series (n = 1) and cohort studies (n = 2). The most commonly reported interacting drugs were amiodarone and ritonavir (bleeding), and phenobarbital, phenytoin, and carbamazepine (thrombosis). Bleeding events more often resulted from a combined mechanism (P-glycoprotein AND CYP3A4 inhibition), whereas thrombotic events resulted from either combined OR single P-glycoprotein/CYP3A4 induction.

CONCLUSION

Current literature evaluating the real-world risk of DOAC DDIs is limited to few case reports and retrospective observational analyses. Clinicians are encouraged to continue to report suspected drug interactions resulting in adverse events.

Venous thromboembolism: current management

Anticoagulation is indicated in most cases of venous thromboembolism

Monotherapy with rivaroxaban or apixaban is the preferred option for most adults with acute venous thromboembolism

There are no recommended dose reductions for rivaroxaban or apixaban in venous thromboembolism, unlike for atrial fibrillation

The initial duration of anticoagulation is usually three months

Extended treatment with low-dose rivaroxaban or apixaban is effective in preventing recurrence in patients with a continuing increased risk of thromboembolism. Both drugs have low rates of major bleeding