Polypharmacy and Potential Drug–Drug Interactions among Ischemic Heart Disease Patients with Comorbidities: A Cross-Sectional Study from a Tertiary Care Center in Eastern India

Abstract Background: Polypharmacy is frequently encountered in ischemic heart disease (IHD), especially in patients with coexisting hypertension and type 2 diabetes mellitus (T2DM). Although multidrug therapy is clinically justified, the risk of potential drug–drug interactions (pDDIs) rises with therapeutic complexity, particularly in older adults. Objective: To evaluate the prevalence of polypharmacy and characterize the patterns and severity of pDDIs in IHD patients with and without cardiometabolic comorbidities in a tertiary care setting. Materials and Methods: This cross-sectional observational study was conducted over 3 months in the General Medicine and Cardiology outpatient departments of a tertiary hospital in Eastern India. One hundred patients with diagnosed IHD were enrolled, including those with isolated IHD, IHD with hypertension, or IHD with hypertension and/or T2DM. Patients with severe hepatic or renal dysfunction were excluded. Prescription data were analyzed for pDDIs using the Medscape Drug Interaction Checker. Statistical analysis was performed with Statistical Package for the Social Sciences v25. Results: The mean age was 57.9 ± 14.5 years; 70% were male. Comorbid hypertension and T2DM were present in 70% of patients, while 6% had isolated IHD. Polypharmacy (≥5 drugs) occurred in 56% of prescriptions, with an average of 6.4 ± 1.2 drugs per patient. Overall, 61% of patients had at least one pDDI. Major interactions occurred in 18% of patients, most commonly aspirin with non-steroidal anti-inflammatory drug, Angiotensin-converting enzyme (ACE) inhibitors with potassium-sparing diuretics, and clopidogrel with proton pump inhibitors. Conclusion: Polypharmacy and clinically important pDDIs are highly prevalent among IHD patients, particularly those with multimorbidity. Incorporating interaction-screening tools, routine medication review, and clinical pharmacist support may improve prescribing safety and optimize outcomes.