Study of drug–Drug interactions among the hypertensive patients in a tertiary care teaching hospital

Aim: Drug–drug interactions (DDIs) are one of the major but preventable cause of adverse drug reaction. Study of prevalence and prediction of DDIs will make the physician easier to provide better patient care and mitigate patient's harm. Hence, the study was planned to evaluate the potential DDIs among medication prescribed to hypertensive patients in our hospital. Materials and Methods: A prospective, cross-sectional study was conducted among the hypertensive patients in medicine (outpatient/inpatient) department over the period of three months in a tertiary care hospital. Adult hypertensive patients of either sex with comorbidities were included in the study. The prescriptions were collected and analyzed for DDI using Medscape interaction checker. Data were analyzed using SPSS (version 16.0) software and expressed in percentage. Pearson's correlation and regression analysis were done. Results: Among 125 patients, 48% were exposed to at least one DDI. Totally 123 DDI were identified and majority of them were significant (85.36%). No serious interactions were identified. Pharmacodynamic and pharmacokinetic drug interactions were found to be 37.39% and 28.76%, respectively. Logistic regression analysis showed advanced male gender and polypharmacy was associated with increased risk of DDI. About 51 interacting pairs of DDI were identified and most frequently occurring pair was amlodipine with atenolol. Aspirin was found to have commonly involved in DDI with enalapril, atenolol, frusemide, spironolactone, carvedilol, and metoprolol. Conclusion: The study highlighted that patients with hypertension are particularly vulnerable to DDI. The comorbidities, advanced age, and polypharmacy are the important factors associated with the occurrence of DDI.