Medicine obviously can't do much good if it sits on a pharmacy shelf. Yet more than one-quarter of the acne patients surveyed by Wake Forest Baptist Medical Center researchers didn't get medications prescribed by their dermatologists.

Among the 143 acne patients who participated in the study, 27 percent failed to obtain all of their medications, including both prescription drugs and over-the-counter products. Those who were prescribed two medications had the highest rate of primary non-adherence - not getting a medication or not using it - at 40 percent, followed by those prescribed three or more medications (31 percent) and those prescribed just one (9 percent). There was no statistically significant difference in non-adherence rates by age or gender in the three treatment-number groups.

"Non-adherence is a pervasive problem in all of medicine, particularly when treating chronic conditions such as acne," said Steven R. Feldman, M.D., Ph.D., professor of dermatology at Wake Forest Baptist and lead author of the study, published online in the March issue of the American Medical Association journal JAMA Dermatology. "A previous study reported a 10 percent primary non-adherence rate for acne patients, so we were surprised that what we found was more than twice that."

The study's results also indicated that prescriptions for were less likely to be filled than those for oral medications; over-the-counter products were less likely to be obtained than ; and paper prescriptions were less likely to be filled than electronic ones. These findings, however, were not statistically significant.

"The study showed that patients are more inclined to follow the treatment regimen when only one medication is prescribed," Feldman said. "Multiple agents are typically required to address the multiple factors that cause acne, but simplifying treatment regimens by prescribing products that contain two or more active ingredients could prove effective in reducing non-adherence."

The study was not designed to determine acne patients' reasons for not getting their prescriptions filled but many of the participants offered unprompted explanations, including cost, forgetfulness, having similar medication on hand, not agreeing with the prescribed treatment and improvement of the skin condition. The researchers suggested that future studies examine these factors to better understand non-adherence to prescribed treatment.

Journal information: JAMA Dermatology