Potential drug-drug interactions between oral anticoagulants for high-risk patients with atrial fibrillation in Latvia

Abstract

Introduction: Atrial fibrillation (AFib) is a disease that affects many people, especially elderly ones. All of these persons have an increased risk of thromboembolic event. For lowering the risk these patients use anticoagulation therapy. There are two types of oral anticoagulants – vitamin K antagonist warfarin and new, known also as direct oral anticoagulants, dabigatran and rivaroxaban. Due to several comorbidities and other complications, e.g. the risk of bleeding and thromboembolism, AFib patients are using different medication simultaneously, therefore increasing the risk of drug-drug interactions because of one metabolism path through P-glycoprotein and CYP450. Monitoring of medical therapy and patient education about most frequent drug-drug interactions using oral anticoagulants could raise attention of health care professionals to the possible drug-drug interactions and promote safe and effective anticoagulation therapy. Aim: To define and analyze the most common potential drug-drug interactions for most frequent used oral anticoagulants – warfarin, dabigatran, rivaroxaban – in patients with high-risk AFib in Latvia. Materials and methods: Quantitative analytic cross-section research was made in time period from October 2016 till June 2017 in Pauls Stradins clinical university hospital, Center of Cardiology in Latvia. The data about patients with high-risk AFib who used oral anticoagulants daily were selected. After signed patients consent form the demographic data, regularly and frequently used medication and food supplements were obtained. Laboratory analysis and echocardiography data were specified with the help of case anamnesis. For statistical data analysis were used SPSS Statistics database. Results: Altogether 143 patients were enrolled in this study, from which 46.2% were male, 53.8% female, with the mean age 69.7 (SD 9.9) years. 53.8% used warfarin, 16.1% dabigatran and 33.6% used rivaroxaban. 49.7% of patients had increased risk of possible drug-drug interactions. For warfarin users the most frequent potential interactions were with omega-3 supplements (20.8%), amiodarone (16.7%) and proton pump inhibitors (13.8%). For dabigatran users the most frequent potential interaction was with proton pump inhibitors (26.1%), amiodarone (17.4%) and omega-3 supplements (13.0%). For rivaroxaban users the most frequent potential drug interaction was with amiodarone (29.2%), omega-3 supplements (16.7%) and non-steroidal anti-inflammatory drugs (4.2%). Conclusion: From all high-risk AFib patients 47.7% had potentially moderate or major risk of drug interactions, most frequently with food supplements. 50.3% patients used warfarin, K vitamin antagonist. The most frequent potential drug interaction in warfarin group was with omega-3 supplements (20.8%) and amiodarone (16.7%), in dabigatran group with proton pump inhibitors (26.1%) and amiodarone (17.4%), in rivaroxaban group with amiodarone (29.2%) and omega-3 supplements (16.7%). Awareness of these interactions between health care professionals could promote the safety and effectiveness of anticoagulation therapy for high-risk atrial fibrillation patients.