Prevalence of Drug-drug Interactions among Outpatients on Anti-platelet or Anticoagulant Therapy at Emergency Department, Phramongkultklao Hospital

Abstract

Background: Antiplatelet and Anticoagulant are an important role in the treatment of ischemic heart disease, valvular heart disease and atrial fibrillation. Drug therapy can lead to drug to drug interaction which pose a significant risk to the patient’s health outcomes. Objective: To access the prevalence of drug to drug interactions among outpatients on anti-platelet or anticoagulant therapy at Emergency Department, Phramongkutklao Hospital. Methods: A retrospective study was done in an electronic medical record from Emergency Department between May 2016 to June 2017. The prescriptions of heart disease patients who were prescribed antiplatelet and anticoagulants from Cardiology outpatient department and Cardiothoracic Surgery outpatient department and then screened for drug to drug interactions using database from Drug interaction facts 2014. The interactions were classified into moderate and severe according to severity scale which was obtained from the DDI database system. Results: The total of 264 prescriptions in 193 patients were included in the study. A proportion of prescription was occupied by patients who were prescribed Aspirin (47.2%), Warfarin 4 (23.8%), Clopidogrel (27.9%) and Dabigatran (1.0%). The incidence of drug to drug interaction among patients who were prescribed Aspirin were 25.8% (p = 0.831), Warfarin 54% (p < 0.001), Clopidogrel 9.1% (p = 0.281) and Dabigatran 0% (p = 0.295). In this study drug to drug interaction significantly occurred among patients who were prescribed warfarin. The major proportion of interactions were between Warfarin and Amiodarone (9%). Conclusion: The study highlighted the drug to drug interaction between antiplatelet or anticoagulants among heart disease patients. Drug to drug interaction significantly occurred among patients who were received warfarin.