Drug labels that use simplified language, in some cases with patient-tested icons, can improve the ability of patients to understand warning labels affixed to prescription drug containers, according to a new study. If patients understand drug warnings, they are more likely to take a particular medicine with food or milk, not drive a car if the drug causes drowsiness, or limit their time in the sun, if the label warns against it. These actions are important for avoiding adverse drug reactions. The researchers found that the rate of correct interpretation of drug warnings was lowest (80.3 percent) among those patients shown standard warnings, higher (90.6 percent) for those shown simplified warning text, and highest (92.1 percent) for patients shown simplified text with icons.
Patients with low literacy (below 7th grade reading level) accounted for 20.1 percent of the study subjects. Low-literacy patients were more likely to be older, black, or have less education than the group as a whole. These patients were 35 percent less likely to correctly interpret standard drug warning labels than those who read at the 9th grade level or higher. Patients with marginal (7th and 8th grade reading levels) or low literacy were two to three times more likely to correctly understand warnings with both simplified text and icons than those with simplified text alone.
The study involved 500 patients seen at 4 outpatient primary care clinics—2 each in Shreveport (Louisiana) and Chicago. The patients were over 18 years old, did not have severe vision or hearing problems, were English-speaking, and were predominantly black women. In each city, 250 patients were equally divided between those seen at an academic general medicine practice and a safety-net community health center. They were presented with containers with the nine most common drug warnings in standard text, simplified text, or simplified text with icons.
Although simplified warning labels helped overcome literacy problems, improved patient counseling by the prescribing clinician or community pharmacist will also be needed to ensure that patients understand how to use the medicines safely, suggest the researchers. Their study was funded in part by the Agency for Healthcare Research and Quality (HS17687).
More details are in "Improving prescription drug warnings to promote patient comprehension," by Michael S. Wolf, Ph.D., M.P.H., Terry C. Davis, Ph.D., Patrick F. Bass, M.D., M.P.H., and others in the January 11, 2010, Archives of Internal Medicine 170(1), pp. 50-56.