OBJECTIVES: To assess the drug-drug interaction in critical care units of tertiary care hospital.

METHODS: The current study is a prospective interventional study. All the patients who satisfied the study criteria were included in the study and patients were followed till their discharge. All the required data were collected and documented in a self-designed data collection from. Each prescription was reviewed separately to identify the drug - drug interactions by using standard references such as Micromedex, Medscape and Stockley’s drug interaction. Each of the identified drug-drug interactions was assessed based on mechanism into either pharmacodynamic interaction or pharmacokinetic interaction, and its severity was assessed using drug interactions severity scale and were categorized into either contraindicated, major, moderate or minor.

RESULTS: Of the 650 patients, a total of 781 drug-drug interaction was identified, among those 781 drug-drug interactions, 705 potential drug-drug interaction was identified in 365 patients and 76 actual drug-drug interactions in 45 patients. The incidence rate of potential drug-drug interaction was 56.1% and the incidence rate of actual drug-drug interactions was found to be 6.9% respectively. Most of the potential drug-drug interaction mechanism was pharmacodynamic interactions 401(56.8) and same on actual drug-drug interaction mechanism was pharmacodynamic interactions 47(61.8%). In the severity scale majority 357(50.6%) was found to be moderate in PDDIs and in severity scale in actual drug-drug interactions majority 39(51.3%) was identified to be moderate. Polypharmacy are also one of the major risk of potential and actual drug-drug interaction in this study.

CONCLUSIONS: The incidence of potential drug-drug interaction was high. Factors such as age, diseases condition, comorbidities and polypharmacy are main key factors for the occurrence of potential and actual drug-drug interactions and the elderly and patients prescribed with six to ten drug are made caution and warranted to minimize or prevent the potential and actual drug-drug interaction in critical care units.