Prevalence and Knowledge of Potential Interactions between Over-the-Counter Products and Apixaban

Background Direct-acting oral anticoagulants (DOACs), such as apixaban, are the most commonly prescribed anticoagulants, with advantages in that they do not require routine monitoring. However, less frequent contact with healthcare professionals may contribute to poor patient knowledge about potential interactions between over-the-counter (OTC) products and DOACs. Objective Determine the prevalence of use of OTC products (OTC medications and dietary supplements) with potentially serious apixaban interactions and assess patient knowledge of potential interactions. Design Cross-sectional survey. Setting Academic-affiliated outpatient medical practices in northern and southern California. Participants A total of 791 English- or Spanish-speaking patients prescribed apixaban. Measurements Use and knowledge of OTC medications and dietary supplements with potentially serious apixaban interactions. Results Almost all respondents (n = 771; 97.5%) reported OTC product use. Of respondents, 33% (n = 266) took at least one OTC product with potentially serious apixaban interactions daily/most days and 53 (6.7%) took multiple products (mean = 2.6 [SD = 2.6]). Aspirin was taken daily by 116 (14.7%; of which 75 [64.7%] also consumed other potentially interacting OTC products), and some days/as needed by an additional 82 (10.4%). Ibuprofen and naproxen were taken daily/most days by 14 (1.8%) and occasionally by 225 (28.5%). Dietary supplements with potentially serious interactions were taken daily/most days by 160 (20.2%). Approximately 66% of respondents were either uncertain or incorrect about the potential for increased bleeding from combining nonsteroidal anti-inflammatory drugs and apixaban. Less knowledge about OTC products with potentially serious interactions was associated with greater OTC product use (odds ratio = 0.54; 95% confidence interval = 0.35-0.85). Conclusion Significant numbers of patients take OTC products (particularly dietary supplements) with potentially serious interactions with the DOAC apixaban and appear to lack knowledge about potentially harmful interactions. Interventions are needed to educate patients and healthcare providers about potential dangers of taking interacting OTC products in combination with apixaban, and data are needed on outcomes associated with concomitant apixaban-OTC product use. J Am Geriatr Soc 68:155-162, 2019.