An Analysis of Drug-Drug Interactions in a Tertiary Care Hospital in Kerala: A Retrospective Study

Abstract

Introduction: Concomitant use of several drugs for a patient is often necessary for achieving therapeutic response. Understanding the profile of Drug-Drug Interactions (DDI) will help health care providers to optimise therapy for better patient outcomes, reinforcing the concept of rational drug use. Aim: To analyse the frequency, mechanisms and severity of DDIs in a tertiary care hospital at Kerala. Materials and Methods: A retrospective cross-sectional study among 350 inpatients of a tertiary care hospital in Kerala from August 2020 to September 2020. Prescriptions containing ≥3 drugs were collected from inpatient medical records. A drug interaction check was performed using the Lexicomp drug interaction checker software. Results: DDIs were present in 74.6% of prescriptions and the average number of interactions was found to be 2.78. Most number for interactions was in the age group 61-80. Average number of DDI was significantly high among patients >60 years. Percentage of prescriptions with DDI and average number of DDI was found to be increasing with increase in number of drugs. Average number of interactions were maximum (5.01) in the group >10. Drug groups most commonly involved in interactions were antiplatelets, oral hypoglycaemic agents, bronchodilators, antibiotics, diuretics, insulin, statins, beta blockers, Proton Pump Inhibitors (PPI) and Non-Steroidal Anti-Inflammatory Drugs (NSAIDs). The most common interventions for minimising the impact of DDIs were changing the timing of drug administration, monitoring for symptoms/signs/lab values/drug levels or both. There was a significant positive correlation between duration of hospital stay and number of DDI. Conclusion: This study threw light upon the pattern and profile of DDIs among inpatients of a tertiary care hospital in Kerala. Elderly people (>60 years) were most prone for DDIs. Percentage of prescriptions with DDI and average number of DDIs was found to be increasing with increase in number of drugs. There was a positive correlation between duration of hospital stay and number of DDI.