Key aspects to optimize inhalation therapy in people with respiratory diseases: a review integrating clinical, technological, and educational evidence

INTRODUCTION: Respiratory diseases represent a significant global health burden, and inhaled drug therapy remains a central component in their management. Despite the availability of effective medications, suboptimal device selection, poor inhaler technique, and limited patient education substantially compromise treatment effectiveness. The expanding diversity of inhaler devices, spacers, and valved holding chambers (VHCs) has enabled more individualized care but has also increased clinical complexity. AREAS COVERED: This review synthesizes current evidence on inhaler device selection and use, with particular emphasis on pressurized metered-dose inhalers combined with spacers or VHCs, chamber characteristics, and dry powder inhalers. It also addresses common inhaler technique errors, hygiene, and maintenance, and the role of educational programs. Evidence from bench studies, clinical trials, pharmacokinetic investigations, and guideline documents is integrated to highlight how device design, patient-related factors, and training interact to determine drug delivery and clinical outcomes. EXPERT OPINION: Optimizing inhaled therapy requires viewing each inhaler-patient pairing as a specific delivery system rather than interchangeable components. Durable antistatic VHCs, appropriate interfaces, and regular technique assessment with targeted education should be the standard of care. Future efforts should prioritize device-specific guidance, scalable education strategies, and implementation research to close the persistent gap between evidence and real-world practice.