Effects of conflicting prescription drug information from direct-to-consumer advertising and drug injury advertising on patients' beliefs and medication adherence

Background: Patients are often exposed to contradictory information about pharmaceutical products from various types of advertising. For example, direct-to-consumer advertising (DTCA) tend to emphasize a drug's benefits, while drug injury advertising emphasizes the worst side effects. Regarding DTCA as a drug information source, many researchers in pharmacy field focus on investigating the misinformation in DTCA and corrective advertising. However, no prior research has examined the effects of such contradictory advertising messages on patients' prescription medicine-related beliefs and medication adherence. This is a significant gap in the research literature on pharmaceutical advertising effects and medication adherence. Objective: This is aimed to examine how exposure to DTCA and drug injury advertising would influence patients' chronic accessibility of drug-related beliefs and their medication adherence behavior. Methods: An online survey was conducted with a sample of 213 patients taking prescription blood thinners. Results: The findings from this study did not support the predicted relationship between exposure to DTCA and consumers' drug-related belief accessibility or their medication adherence. However, this study found a significant interaction effect of exposure to DTCA and exposure to drug injury ads on patients' medication adherence. The analysis results demonstrate that, for those who were exposed to drug injury ads, a significant negative relationship emerged between DTCA exposure and medication adherence. Conclusion: This study provides important empirical evidence of a negative interaction effect of exposure to DTCA and drug injury ads on patients' medication adherence, which demonstrates that the influence of DTCA and drug injury ad exposures on patients' medication adherence is not independent, separate process but an interactive process. A communication campaign with corrective advertising could alleviate the negative interaction effect of exposure to contradictory information from different types of pharmaceutical ads on patients' medication adherence.