Understanding older adults' medication decision making and behavior: A study on over-the-counter (OTC) anticholinergic medications

Background: Older adults purchase and use over-the-counter (OTC) medications with potentially significant adverse effects. Some OTC medications, such as those with anticholinergic effects, are relatively contraindicated for use by older adults due to evidence of impaired cognition and other adverse effects. Objective: To inform the design of future OTC medication safety interventions for older adults, this study investigated consumers' decision making and behavior related to OTC medication purchasing and use, with a focus on OTC anticholinergic medications. Methods: The study had a cross-sectional design with multiple methods. A total of 84 adults participated in qualitative research interviews (n=24), in-store shopper observations (n=39), and laboratory-based simulated OTC shopping tasks (n=21). Simulated shopping participants also rank-ordered eight factors on their importance for OTC decision making. Results: Findings revealed that many participants had concerns about medication adverse effects, generally, but were not aware of age-related risk associated with the use of anticholinergic medications. Analyses produced a map of the workflow of OTC-related behavior and decision making as well as related barriers such as difficulty locating medications or comparing them to an alternative. Participants reported effectiveness, adverse effects or health risks, and price as most important to their OTC medication purchase and use decisions. A persona analysis identified two types of consumers: the habit follower, who frequently purchased OTC medications and considered them safe; and the deliberator, who was more likely to weigh their options and consider alternatives to OTC medications. Conclusion: A conceptual model of OTC medication purchase and use is presented. Drawing on study findings and behavioral theories, the model depicts dual processes for OTC medication decision making - habit-based and deliberation-based - as well as the antecedents and consequences of decision making. This model suggests several design directions for consumer-oriented interventions to promote OTC medication safety.