According to a new study, different color of generic pills may discourage people from using them, which can have some serious side-effects.

Generic pills have different shapes and sizes, unlike the brand-name versions that have distinct color. Researchers say that this difference can affect peoples' ability to stick to prescription pills. They suggest that taking steps to ensure that the generic pills for a condition are similar might get more people adhere to prescription drugs.

"Pill appearance has long been suspected to be linked to medication adherence, yet this is the first empirical analysis that we know of that directly links pills' physical characteristics to patients' adherence behavior. We found that changes in pill color significantly increase the odds that patients will stop taking their drugs as prescribed," explained Aaron S. Kesselheim, from BWH, and principal investigator of this study.

Researchers used data from a large national database of filled prescriptions of patients taking antiepileptic drugs. Discontinuing antiepileptic drugs, even for a few days, can have serious consequences.

The study included more than 11,000 patients who hadn't refilled their generic pill prescription for more than 10 days. Researchers then compared the study patients to 50,000 patients who had refilled the prescription. They found that patients whose pills had changed color were 27 percent more likely to avoid next refill than people whose pills hadn't changed color, Livescience reports

"Patients should be aware that their pills may change color and shape, but that even differently-appearing generic drugs are approved by the FDA as being bioequivalent to their brand-name counterparts and are safe to take. Physicians should be aware that changes in pill appearance might explain their patients' non-adherence. Finally, pharmacists should make a point to tell patients about the change in color and shape when they change generic suppliers," Kesselheim explained.

The study is published in the journal the Archives of Internal Medicine.