How Skin Tone Influences Medication Effectiveness and Safety

Scientists at UC Riverside have reported how skin pigmentation affects medication effectiveness, urging a shift in drug testing practices to ensure safer, more effective treatments for diverse populations.

Researchers at the University of California, Riverside, have reported that skin pigmentation could significantly impact how medications perform, suggesting that the current drug development process might be shortchanging people with varying skin tones.

In a perspective article published in the journal Human Genomics, Simon Groen, an assistant professor of evolutionary systems biology, and Sophie Zaaijer, a diversity, equity and inclusion (DEI) consultant and researcher, highlight the previously overlooked role of melanin — the pigment responsible for skin color — in binding with drug compounds. This interaction could influence the speed and efficacy with which medications reach their intended targets.

“Our review paper concludes that melanin, the pigment responsible for skin color, shows a surprising affinity for certain drug compounds,” Groen said in a news release.

This revelation raises critical questions about the effectiveness of standard medication dosages, given the significant variation in skin tones among individuals.

Current Food and Drug Administration (FDA) guidelines for drug toxicity testing fail to account for these pigmentation differences, a concerning oversight as the FDA pushes for more diverse clinical trials through its Diversity Action Plan.

“This oversight is particularly concerning given the push for more diverse clinical trials, as outlined in the agency’s Diversity Action Plan,” Zaaijer said in the news release. “But current early-stage drug development practices still primarily focus on drug testing in white populations of Northern European descent.”

One striking example the researchers cited involves nicotine. Melanin’s affinity for this compound could mean that nicotine patches used in smoking cessation may be less effective for individuals with darker skin tones. This calls into question whether current public health interventions adequately serve all demographic groups.

“Are we inadvertently shortchanging smokers with darker skin tones if they turn to these patches in their attempts to quit?” Groen added.

To address these disparities, Groen and Zaaijer are advocating for the use of human 3D skin models with varying pigmentation levels. These models could help pharmaceutical companies more accurately assess drug binding properties across different skin types.

“Skin pigmentation should be considered as a factor in safety and dosing estimates,” added Zaaijer. “We stand on the brink of a transformative era in the biomedical industry, where embracing inclusivity is not just an option anymore but a necessity.”

The broader implications of their work extend beyond skin pigmentation. Genetic variations among minority groups can result in significantly different drug responses across races and ethnicities, impacting up to 20% of all medications, the researchers noted.

“Yet, our molecular understanding of these differences remains very limited,” Zaaijer said.

Groen and Zaaijer urge that a more inclusive drug development process is essential, not only to comply with new mandates like the Food and Drug Omnibus Reform Act enacted in 2022, but to build trust among diverse patient groups. They believe these changes require a collaborative effort among academics, industry researchers, clinicians and regulators.

“It’s a monumental task, requiring clear lines of communication between academics, industry researchers, clinicians and regulators,” Zaaijer said. “The future of medicine relies on our capacity to connect these currently isolated operational teams.”

The researchers are also calling on patients and their advocates to ask critical questions about drug efficacy and safety related to their specific ancestral backgrounds.

In summary, the findings emphasize the necessity for the pharmaceutical industry and regulatory bodies to embrace inclusive testing practices. As we advance toward these goals, the hope is for a future where treatments are tailored to meet the diverse needs of all patients, ensuring no one is left behind in the realm of medical advancements.