Prevalence, types and predictors of potential drug-drug interactions in pulmonology ward of a tertiary care hospital

The objective of the study was to identify prevalence, types and predictors of potential drug-drug interactions (pDDIs) in pulmonology ward and to report common interactions. Medical records of 400 randomly-selected patients were reviewed for pDDIs using Micromedex Drug-Reax software. Logistic-regression was applied to determine predictors of pDDIs. We identified 126 interacting-combinations that encountered in total 558 pDDIs with median number of 01 pDDI per patient. Overall 45% patients had at least one pDDI; 24.25% were having at least one major pDDI, and 36% patients had at least one moderate pDDI. Among 558 identified pDDIs, most were of moderate (53.6%) or major severity (34%); good (74.2%) or fair (16.3%) type of scientific-evidence; and delayed onset (70%). Top 15 common pDDIs included 6 major, 7 moderate and 2 minor interactions. There was significant association of the occurrence of pDDIs with patient with age of 60 years or more (p <0.001), hospital stay of 7 days or longer (p = 0.01) and taking 7 or more drugs (p <0.001). We have recorded a high prevalence of pDDIs in pulmonology ward, most of which were of moderate severity. Patients with old age, long hospital stay and increased number of drugs were more exposed to pDDIs.