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Side Effect Information and the Influence on Patient Medicine-Taking Behaviour



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Lack of patient adherence with medication results in health care costs and adverse clinical outcomes. Although fear of side effects can contribute to non-adherence, being informed about them can actually improve matters. Nonetheless, questions persist as to the most efficient way to convey that type of information to patients for a given medication. Information on side effects is largely limited to a simple list in medication leaflets, often without frequency data (that is, lacking detail as to how often they might occur). The decision-making literature suggests that the interpretation of information varies depending on the presentation format or the frame used. This study examined the impact of providing numerical information for side effect frequency, levels of illness severity, and side effect framing on the likelihood of taking an OTC medicine. Participants received a headache scenario with three drug options (X, Y and Z) to consider for use. These painkillers had three levels of potency (defined as 50, 75, and 100% effective) and were accompanied with three levels of side effects (two, four, and six items). When considering their drug choice for the headaches, participants received drug information written without side effect frequency data, then again with side effect frequency data. Subjects rated their likelihood of taking Drug X, Y and Z on a scale of 1 (very unlikely) to 100 (very likely). Participants were also asked to show their likelihood of taking a different set of two medications for headaches (coined Drug N and P) based on positively-slanted or negatively-slanted wording in relation to chances of experiencing a side effect (heartburn). Thirty subjects from Saskatoon over 50 years of age participated. The average age was 66.6 years and 63.3 percent of participants were female. Less than half of participants (n=11) had previous experience with side effects. Most participants were using at least one medicine (whether OTC or prescribed) and described themselves as knowledgeable or somewhat knowledgeable. Participants were more likely to take the hypothetical drugs in the situations described when they received frequency data for side effects (p



Risk literacy, Health literacy, Numarical information, Decision-making, Medication side effects



Master of Science (M.Sc.)


College of Pharmacy and Nutrition


College of Pharmacy and Nutrition


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