PHARMACOVIGILANT ANALYSIS OF DRUG–DRUG INTERACTIONS ASSOCIATED WITH POLYPHARMACY IN CARDIAC PATIENTS AT GOVERNMENTAL HOSPITALS IN HYDERABAD, PAKISTAN

Abstract

Background/Objectives: Cardiovascular diseases (CVDs) remain as the leading cause of global morbidity and mortality and require long-term, multiple medication therapy.  In Pakistan, the widespread use of multiple medications combined with the overall high prevalence of CVDs greatly increases the chances of drug-drug interactions (DDIs). This study was designed to evaluate the prevalence, patterns, severity, and clinical outcomes of DDIs among cardiac patients who used polypharmacy while being admitted to government hospitals in Hyderabad, Pakistan.  It also sought to evaluate the relationship between polypharmacy and the number of DDIs present, and to discuss the relationship between the severity of the DDIs and patient survival using Kaplan-Meier analysis. Methods: A retrospective cross-sectional observational design was used.  Data was collected from 400 adult cardiac patients (≥18 years old) who were taking ≥ 5 medications.  Sociodemographic, clinical and medication information was collected through a structured questionnaire.  Drug-drug interactions were detected using standard interaction checkers and classified by type (PK/PD), severity (mild, moderate, severe), and clinical outcome.  Statistical analysis was performed using IBM SPSS (version 28) using descriptive, and inferential methods including chi-square tests and Kaplan-Meier survival analysis. Results: Out of 400 patients examined, polypharmacy was found to be common, averaging 9 medications per individual. At least one DDI was identified in 53% of prescriptions, with severe DDIs being most common (23% of total), followed by moderate (15%) and mild (15%). Most commonly found serious DDI combinations were: Anticoagulants and NSAIDS; Statins and Fibrates; Sacubitril/valsartan and ACE Inhibitors; Warfarin and Amiodarone. The clinical outcomes analyzed showed 25% dose reductions; 15% discontinuation; 60% no change to therapy. Kaplan-Meier studies [23] indicated that patients with severe DDIs had lower survival rates. Conclusion: This study demonstrates the significant incidence of clinically relevant drug intervention (DDI) occurrences in cardiac patients with multiple medications treated in Pakistan. The presence of severe DDIs correlates with an increased risk of death; therefore, implementation of more comprehensive pharmacovigilance, use of DDI checking algorithms, and enhancement of clinical provider knowledge regarding the avoidance of DDIs, are necessary elements to assure patient safety and improvement of therapeutic outcomes.