Background: Drug–drug interactions (DDIs) represent a significant risk to patient safety, especially in settings where polypharmacy is common and decision-support systems are limited. This study aimed to assess the prevalence, types, mechanisms, and clinical predictors of potential drug–drug interactions in inpatient and outpatient drug prescriptions.
Methods: A cross-sectional study was conducted on 300 prescriptions collected from inpatient and outpatient departments in Sulaymaniyah city, between January and April 2025. The Medscape Drug Interaction Checker was used to identify and classify drug-drug interactions by severity (minor, moderate, major) and mechanism (pharmacokinetic, pharmacodynamic, or both). Associations with polypharmacy, gender, and care setting were analyzed using appropriate statistical analysis.
Results: Potential drug-drug interactions were identified in 81 prescriptions (27.0%), with a total of 148 interactions. Polypharmacy was strongly associated with drug-drug interaction occurrence: patients with five or more medications had significantly higher odds of drug-drug interactions (OR = 9.24; 95% CI: 4.31–19.78; p < 0.001), which increased further for those prescribed six or more drugs (OR = 16.25; 95% CI: 7.67–34.42). Most drug-drug interactions were moderate in severity (51.3%) and primarily pharmacodynamic in nature (57.4%). Gender and care setting were not significantly associated with drug-drug interaction risk.
Conclusion: Drug–drug interactions were common in Northern Iraq prescriptions, especially with polypharmacy, underscoring the need for better medication review and monitoring.