Medication non-adherence as a driver of pharmaceutical waste: integrating top-down policies with bottom-up practice.

Medication non-adherence is a widespread challenge affecting up to half of patients with chronic conditions, with profound implications for health outcomes, healthcare costs, and, increasingly recognized, environmental sustainability. Unused and improperly disposed medications contribute to pharmaceutical waste, overproduction, and pollution, amplifying the healthcare sector's carbon footprint. This viewpoint highlights the need for coordinated action across clinical practice and health policy to mitigate this underappreciated dimension of environmental harm. We argue that addressing non-adherence is not solely a clinical imperative but also an ecological one, requiring dual responsibility: bottom-up engagement by healthcare professionals and patients, and top-down strategies embedded in policy and system-level reforms. Drawing on evidence from adherence interventions and sustainable prescribing initiatives, we outline actionable steps-from individualized medication optimization and deprescribing to public health campaigns and regulatory frameworks-to align adherence management with environmental goals. Tackling this problem offers a unique opportunity to improve patient outcomes while advancing climate-conscious healthcare and reducing overall healthcare-related costs. We call on clinicians, health systems, and policymakers to integrate adherence promotion into sustainability agendas and to view every prescription as both a therapeutic and environmental decision. Likewise, we urge optimization of environmentally safe and effective disposal systems for unused and expired drugs, ensuring that such measures become an integral part of comprehensive strategies to protect both human health and the planet.