Medication and health-related outcomes by prescription lengths: A systematic review.

Background: Prescription length policies (such as 30, 60, or 90 days) influence medication adherence, healthcare access, costs, and patient safety. However, their overall impact remains unclear because of heterogeneous evidence. Objectives: This systematic review evaluated the effects of prescription length on clinical, economic, and healthcare system outcomes and identified methodological considerations for future research and policy. Methods: PubMed, Scopus, and ScienceDirect were searched for studies published from 2000 to July 1, 2026. Studies comparing different prescription lengths were included, while those unavailable in full text were excluded. Methodological quality was assessed using design-specific critical appraisal tools. Due to substantial heterogeneity in study designs, populations, prescription durations, and outcome measures, findings were synthesized narratively. Results: Twenty-three studies were included. Longer prescription durations were generally associated with improved medication adherence and increased medication waste. Evidence for economic, clinical and healthcare utilization outcomes was more limited and heterogeneous. Among studies of chronic disease management, longer prescription durations were generally associated with lower out-of-pocket costs, transportation cost and patient time cost, and reduced healthcare encounters, although findings for total economic outcomes varied according to the analytical perspective adopted. For acute conditions with opioid use, shorter prescription durations were associated with reduced adverse outcomes, including overdose risk and persistent opioid use. Methodological heterogeneity in study design, outcome definitions, and analytical perspectives contributed to differences in findings across studies. Conclusion: Longer prescription lengths were consistently associated with improved medication adherence but also increased medication waste. Evidence for clinical, economic, and healthcare system outcomes remains limited and heterogeneous and should be interpreted according to medication type and clinical context. Thus, a single prescription duration is unlikely to be appropriate across all settings. Healthcare providers and policymakers should consider medication type, patient needs, treatment stability, and healthcare system context when determining prescription duration. Further well-designed studies using transparent and comparable outcome definitions are needed to strengthen the evidence base for prescription-length decision-making.