BACKGROUND: Many patients taking direct-acting oral anticoagulants (DOACs) also consume over-the-counter (OTC) products (dietary supplements and OTC medications), yet many lack knowledge of potential interactions that may increase or decrease DOAC efficacy and may not seek information about OTC products. The objective of this study was to describe patient attitudes and beliefs that inhibited information seeking about potential apixaban-OTC product interactions.

METHODS: Participants included English-, Spanish-, Mandarin-, and Cantonese-speaking adults from two large academic medical centers who reported taking apixaban (a frequently prescribed DOAC) in the past month. Thematic analysis was performed on semi-structured interviews.

RESULTS: Sixty patients aged 24-93 years (mean = 65.3; SD = 15.6) were interviewed; 55% were women. Participants took a total of 236 OTC products. Those with potential interactions with apixaban warranting consideration for therapy modification included: ibuprofen (n = 14; 5.9%), aspirin (n = 8; 3.4%), and naproxen (n = 3; 1.3%). Interviews revealed 5 major themes related to a lack of information-seeking about OTC products: (1) patients lack awareness of the potential for interactions; (2) patients believe that OTC products are safe and/or regulated (largely because they were familiar with the products, had previously taken them, or assumed that dietary supplements were regulated by the Food and Drug Administration); (3) patients believe that providers are responsible for alerting patients about potential interactions (as patients assumed that providers were aware of their OTC product use); (4) patients had prior knowledge of and/or used OTC products infrequently; and (5) obtaining information can be inconvenient. Inquiries regarding preferred information sources revealed 59 (98.3%) patients most frequently sought or would seek information from physicians and 34 (56.7%) from the internet.

CONCLUSIONS: Patients taking apixaban raised reasons for not seeking information about potential OTC product interactions that included poor awareness, perceptions regarding the safety of OTC products, and beliefs in provider responsibility for informing them about interactions. Greater patient education is needed regarding the potential for OTC product-DOAC interactions and the regulation of OTC products, particularly dietary supplements.