Dangerous Double Dosing: How Naive Beliefs Can Contribute to Unintentional Overdose with Over-the-Counter Drugs

In a series of studies, consumers reviewed over-the-counter (OTC) drug packages and evaluated these drugs for concurrent use. The authors investigate whether the consumers utilized the active ingredients listed on the package and recognized the risks of double dosing when using two drugs with the same active ingredient. Both novice and expert consumers used the active ingredients to assess drug similarity, indicating that the information was accessible. However, only medically trained experts used this information to assess the risks of taking two drugs concurrently, indicating that they understood its diagnosticity or relevancy. Novices' failure to view double dosing as risky suggests that they might hold a naive belief that OTC drugs are relatively risk free; thus, the authors test interventions to increase active ingredient diagnosticity versus accessibility. One intervention considered by OTC drug manufacturers makes active ingredients more accessible on packages using icons. However, the authors found this approach alone to be ineffective, whereas interventions enhancing the diagnosticity of ingredients through public service messages or package warnings yielded promising results. Thus, interventions may benefit by going beyond accessibility to also highlight active ingredient diagnosticity.