Anti-factor Xa Monitoring and Activated Charcoal for a Pediatric Patient With Rivaroxaban Overdose

Massive Apixaban Overdose Confirmed with Blood Concentrations and Managed Without Bleeding: A Single Case Report

Background: Acute overdoses of apixaban, and other direct oral anticoagulants are relatively uncommon. The number of direct oral anticoagulants prescriptions in the United States is increasing, however reports on patient outcomes after documented overdose are sparse. Case report: A 76-year-old man with a past medical history of atrial fibrillation and taking apixaban 5 mg twice daily presented to the emergency department 10 hours after reportedly ingesting 60-70 of his pills. He was alert and had a normal physical examination. Blood tests demonstrated an INR of 12, platelets of 161 000 cells/mm3, hemoglobin 9.7 g/dL, and creatinine 1.81 mg/dL. He received 60 g of activated charcoal and 4 units of fresh frozen plasma prophylactically. Initial blood apixaban concentration was 4 000 ng/mL. Repeat blood apixaban concentrations were 3 000 ng/mL and 2 200 ng/mL at 7 and 14 hours, respectively (thrapeutic range 91-321 ng/mL for a 5 mg twice daily dose). The hybrid anti-factor Xa activity did not correlate with blood apixaban concentrations. Apixaban elimination followed first-order kinetics with an apparent elimination half-life of 14 hours in the presence of impaired renal function. He did not have any minor or major bleeding events.

Nomogram for predicting bleeding events in nonvalvular atrial fibrillation patients receiving rivaroxaban: A retrospective study

Background and Aims

To construct a bleeding events prediction model of nonvalvular atrial fibrillation (NVAF) patients receiving rivaroxaban.

Methods

We conducted a retrospective cohort study in patients with NVAF who received rivaroxaban from June 2017 to March 2019. Demographic information and clinical characteristics were obtained from the electronic medical system. Univariate analysis was used to find the primary predictive factors of bleeding events in patients receiving rivaroxaban. Multiple analysis was conducted to screen the primary independent predictive factors selected from the univariate analysis. Finally, the independent influencing factors were applied to build a prediction model by using R software; then, a nomogram was established according to the selected variables visually, and the sensitivity and specificity of the model was evaluated.

Results

Twelve primary predictive factors were selected by univariate analysis from 46 variables, and multivariate analysis showed that older age, higher prothrombin time (PT) values, history of heart failure and stroke were independent risk factors of bleeding events. The area under curve (AUC) for this novel nomogram model was 0.828 (95% CI: 0.763-0.894). The mean AUC over 10-fold stratified cross-validation was 0.787, and subgroup analysis validation also showed a satisfied AUC. In addition, the decision curve analysis showed that the PT in combination with CHA2DS2-VASc and HASBLED was more practical and accurate for predicting bleeding events than using CHA2DS2-VASc and HASBLED alone.

Conclusions

PT in combination with CHA2DS2-VASc and HASBLED could be considered as a more practical and accurate method for predicting bleeding events in patients taking rivaroxaban.

Pharmacokinetics of a microdosed cocktail of three direct oral anticoagulants in children with congenital heart defects: study protocol for a single-centre clinical trial (DOAC-Child)

INTRODUCTION

Direct oral anticoagulants (DOACs) are direct inhibitors of coagulation factor Xa and are frequently used in adults for different indications such as deep vein thrombosis or non-valvular atrial fibrillation. Paediatric patients might benefit as well from DOACs because the simplicity and convenience of their use is likely to decrease physical and psychological stress related to invasive procedures associated with phenprocoumon and heparin therapy. Thus, it is expected that the future use of DOACs will ultimately improve compliance and overall safety of anticoagulant therapies in paediatric populations. To assure safe and effective use the clinical pharmacology and pharmacokinetics (PK) of these drugs need to be evaluated in children.

METHODS AND ANALYSIS

This study is a single-centre, open-label, clinical trial in a paediatric population with non-cyanotic congenital heart defects. After having obtained informed consent from the parents, each participant will receive a single oral administration of a drinkable solution of a microdose cocktail of three FXa inhibitors consisting of apixaban (12.5 µg), rivaroxaban (12.5 µg), edoxaban (50 µg), plus a microdose of the two probe drugs midazolam (10 µg) and yohimbine (25 µg). Serial blood samples (n=up to 20) will be collected at specified time points before and up to 25 hours after cocktail administration. The primary PK endpoint will be the area under the plasma concentration time curve of apixaban, rivaroxaban and edoxaban. Secondary PK outcomes will be C_max, t_max, t_1/2, Cl/F and V_ss/F. Safety and tolerability of the microdose cocktail will be evaluated as well by a collection of adverse events.

ETHICS

This study has been approved by the responsible Ethics Committee of the Medical Faculty of Heidelberg University.

DISSEMINATION

Study results will be presented at international scientific meetings and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

EudraCT 2019-001759-38 16, DRKS00021455.

Direct oral anticoagulants toxicity in children: an overview and practical guide

INTRODUCTION

By increasing use of direct oral anticoagulants (DOACs) in adults and children, gradual increase in the number of intentional or unintentional DOAC poisonings among children is suspected in the near future. Hence, clinicians and pharmacists need to be familiar with the clinical features and management of DOAC-toxicity among pediatric population.

AREAS COVERED

This article provides an overview and practical guide to DOAC-toxicity in pediatrics according to the available clinical evidence.

EXPERT OPINION

Based on limited available data, accidental pediatric ingestion of DOACs can be managed by supportive care in most cases. However, serious toxicity may occur following massive overdose, in presence of underlying disorders (renal or hepatic dysfunction) and concurrent anticoagulant therapy. Activated charcoal is recommended for known recent ingestion of DOACs (within 2-4 hours) to reduce the gastrointestinal absorption. Supportive interventions including local hemostatic measures and volume resuscitation are the cornerstone of management of bleeding. Vitamin K and fresh frozen plasma are ineffective for DOAC reversal and thus are not recommended. Currently, safety and efficacy data regarding the use of specific reversal agents (including idarucizumab and andexanet alfa) and 3-factor or 4-factor prothrombin complex concentrate (PCC) or activated PCC (aPCC) among children with DOAC-associated bleeding are lacking.

Two Cases of Acute Direct Oral Anticoagulant Overdose Without Adverse Effect

We report 2 pediatric patients who had acute overdoses of the direct oral anticoagulants medications. Both patients were managed conservatively; neither required reversal agents or blood products nor had any major or minor bleeding events. With therapeutic usage of direct oral anticoagulants, routine coagulation studies typically are considered insufficient measures of anticoagulation and the preferred chromogenic anti-Factor Xa assay is recommended but not widely available. Using a routine hybrid heparin anti-Factor Xa assay, 1 patient demonstrated a strong linear correlation up to a serum rivaroxaban concentration of 940 ng/mL.

Conservative management of massive rivaroxaban overdose: A case report and literature review

In the cases of acute rivaroxaban overdose, conservative management without prothrombin complex concentrate or other coagulation factors may be sufficient if renal function is normal and there is no bleeding.