Older study participants were less likely to look at warning labels on prescription drug bottles than younger ones, suggesting that they would be more vulnerable to adverse drug effects.
Brightly colored warning labels affixed to prescription pill bottles are designed to grab patients’ attention and provide information necessary to ensure safe use: “Do not consume alcohol while taking this medication,” for instance. To find out how effective these warning labels are at getting their message across, researchers at Michigan State University conducted a study that investigated how likely patients were to look at and recall labels printed in a variety of colors
. Their results, published online on June 14, 2012, in PLoS ONE
, are not encouraging.
The study included 32 participants, 15 of whom were between the ages of 20 and 29 and 17 of whom were over the age of 50. Each participant was presented with 5 pill bottles, each with a warning label printed in a different color combination: black text on blue, yellow, white, and red backgrounds and blue text on a white background. As the participants examined each bottle, eye tracking software monitored for how long and how often they looked at the bottle cap, the white pharmacy label, and the warning label.
The results showed that the older participants looked at the warning label 54.0% of the time, while the younger participants looked at it 91.8% of the time. Among the older participants, 29% looked at all 5 warning labels and 29% looked at none of them. For younger participants, the corresponding rates were 73% and 13%. However, the different warning label color schemes had no effect on the likelihood that participants would notice them.
Next, participants were presented with 10 warning labels, 5 of which were the ones they had seen on the pill bottles, and 5 of which had the same warning message but used different colors. The participants were asked to identify which of the 10 labels they had been shown previously. The probability of the younger participants correctly identifying whether they had seen these labels was 68.5%, compared with 53.6% for the older participants. The lower recognition rate among older participants was attributed entirely to their lower rate of noticing the warning labels in the first part of the experiment rather than to memory problems.
Based on their findings, the researchers note that if a warning label can catch a patient’s attention, it is likely to have its intended effect. They also note that older patients, who take more medications and are therefore more vulnerable to adverse drug effects, are less likely to take note of warning labels. Although the study found that varying the labels’ color scheme had no effect on the rate at which participants noticed them, it also found that all participants looked at the white pharmacy label. Therefore, the authors note, warning labels might be more noticeable if they were placed right next to the white label rather than elsewhere on the pill bottle.