Pill Shape, Color Impact Patient's Perception of Effectiveness
Research in the journal Food Quality and Preference sheds new insight into the role of pill color and shape in influencing patient perceptions on expected ease/difficulty of swallowing, taste, and/or efficacy – which may influence medication adherence and treatment compliance.
Perceived bitterness or metallic taste may contribute to poor medication adherence and compliance; while some drug manufacturers have encapsulated bitter-tasting compounds so they do not come into direct contact with the patient's mouth, this is not feasible for all medications. In the study, researchers conducted two experiments to evaluate how cues from the color and shape of tablets could affect expected ease/difficulty of swallowing, taste, and/or possible efficacy of medications. In the first experiment, 97 participants from the United States viewed online photos of tablets having one of seven colors and three shapes (21 tablets total): circular-, oval-, and diamond-shaped tablets colored red, light-red, green, light-green, blue, light-blue, and unmodified as white. The participants ranked the tablets based on expected difficulty of swallowing, expected bitterness, expected alerting effect, and expected efficacy solely from visual elements of the tablets.
The participants reported that they expected the blue and light-blue tablets to taste less bitter than the other colors and red and light-red were expected to be more alerting compared to the other colors. White tablets were ranked as having an expected greater efficacy in treating symptoms of headaches. Diamond-shaped tablets were expected to be most difficult to swallow, whereas oval-shaped tablets were perceived to be the least bitter, the least effective in treating headache symptoms, and less alerting than the diamond-shapes tablets.
In the second experiment, 337 participants from China, Colombia, and the U.S. completed the same tasks but pink, yellow, and orange were also now included. Participants also had to also complete a color identification task at the end to ensure that they had accurately identified the correct color category.
Among the participants from China, white tablets were seen as having the greatest efficacy in treating headaches. Diamond-shaped tablets had high expected difficulty in swallowing and were seen as most alerting. The least bitter tablets were oval-shaped but also were least effective for treating headaches. Circular-shaped tablets were easiest to swallow and most effective for headache. For colors, red and blue tablets were expected to be hardest to swallow, red and green tablets more bitter, red tablets most alerting, and white tablets most effective in treating headaches.
The Colombian participants viewed pink and white tablets as tasting less bitter than the other colors; oval-shaped tablets were the least bitter and least effective for headache, while diamond-shaped tablets were hardest to swallow. Red tablets were seen as the most alerting and white tablets were expected to be most effective at treating symptoms of headache.
Lastly, the U.S. group viewed yellow and white tablets as less bitter, red and orange as more alerting, and white tablets as most effective in treating headache. Diamond-shaped tablets were the most difficult to swallow and oval-shaped ones were the least bitter, least effective, and most alerting. For shape, circular tablets were easiest to swallow and most effective in treating headaches. No significant differences were seen between results of the red and light-red, blue and light-blue, or green and light-green findings in any of the groups.
The cultural variations observed in the results suggest that there is no one color or shape that is optimal for pills in general. If patients have poor medication adherence based on complaints of difficulty of swallowing or taste, clinicians should also examine the shape and color of the drug for potential biases.
For more information visit Elsevier.com.