Abstract
Intoduction: Patients with Chronic Obstructive Pulmonary Disease (COPD) are vulnerable to multimorbidity and polypharmacy because bronchodilator regimens are frequently combined with therapies for comorbid conditions, increasing the risk of pharmacokinetic and pharmacodynamic drug-drug interactions (DDIs). This review aimed to identify the specific patterns, causal mechanisms, and severity of DDIs in COPD regimens and to formulate clinical mitigation strategies. Method: This narrative literature review adopted PRISMA 2020 principles and extracted 11 primary and secondary studies from PubMed/MEDLINE, ScienceDirect, SpringerLink, Wiley Online Library, and Google Scholar, focusing on publications from 2021–2026 while retaining fundamental references that remained relevant. Result and Discussion: The cumulative prevalence of DDIs reached 72.2% and increased to 96% during hospitalization for acute exacerbations. DDIs were predominantly pharmacodynamic, particularly additive QT-interval prolongation and INR modulation, with pharmacokinetic interactions involving cytochrome P450 pathways. Severity was dominated by moderate (52.8%) and major (25.1%) interactions. Conclusion: DDI risk in COPD is complex and supports the need for medication reconciliation, structured pharmacist-led medication review, and targeted clinical monitoring during transitions of care to reduce preventable drug-related harm.