Abstract Background Medication nonadherence is a pervasive and multifactorial challenge that substantially undermines therapeutic effectiveness, increases morbidity and mortality, and imposes a significant economic burden on healthcare systems. Despite advances in pharmacotherapy, a considerable proportion of patients fail to take medications as prescribed due to a complex interplay of patient-related, therapy-related, healthcare system, and socioeconomic factors. Conventional approaches often address adherence in isolation, overlooking the need for integrated strategies that span both clinical practice and pharmaceutical design. Main body This narrative review synthesizes current evidence on the epidemiology, determinants, and clinical and economic burden of medication nonadherence, while critically examining interventions aimed at improving adherence. Particular emphasis is placed on the synergistic integration of clinical strategies—such as patient education, behavioral and motivational support, regimen simplification, pharmacist-led adherence programs, and digital health technologies—with pharmaceutical formulation and drug delivery innovations. These include taste masking technologies, modified- and long-acting dosage forms, alternative delivery systems, fixed-dose combinations, and personalized formulations designed to align therapy with patient preferences and capabilities. By bridging perspectives from clinical pharmacy and pharmaceutical technology, the review highlights the central role of pharmacists within multidisciplinary adherence frameworks and underscores the value of patient-centered, system-level approaches. Current limitations, including heterogeneity in adherence measurement, variable intervention effectiveness, and challenges in real-world implementation, are also discussed. Conclusion An integrated, patient-centered approach that combines clinical interventions with pharmaceutical formulation and delivery innovations represents a promising strategy to improve medication adherence and optimize therapeutic outcomes. Future efforts should focus on generating robust real-world evidence, leveraging digital and personalized medicine technologies, and strengthening collaborative implementation models to enhance adherence and improve healthcare system efficiency.
Elmokadem et al. (2026) studied this question.