Evaluation of potential drug-drug interactions in hospitalized patients at a tertiary care hospital: A pilot study

Drug-drug interactions (DDIs) are termed as alteration of drug response with concurrent use of another drug. DDIs which are responsible from 20-30% of all adverse drug reactions lead to preventable morbidity and mortality, prolonged hospital stay and higher financial burden. The aim of this retrospective study was evaluation of prevalence and severity of potential DDIs in inpatient settings. We conducted this study between February-April 2019 in inpatient services of Farabi Hospital of Karadeniz Technical University. Data which consist of patient demographic features and drugs used by patients were obtained from patient files and case sheets. In this study, 25 patients (68% female; 32% male) were included; the mean age of the subjects was 63.32 ± 15.72 years. The drugs were analyzed for the potential DDIs using Lexi-InteractTM Online which is available on the www.uptodate.com. According to our results the prevalence of potential DDIs which involve alimentary tract and metabolism drugs (n=69, 27.4%) followed by cardiovascular system drugs (n =43; 17.06 %) were common among the drugs. The average number of drugs received in the units were similar. The total number of pDDIs determined as 204, and the mean number of pDDIs per patient was 8.16±6.4 in the units. It is identified that among the total drug interactions 76.5% in the risk category C (monitor therapy), 15.2% in the risk category B (no action needed), and 4.4% in the risk category D (consider therapy modification). The highest total number of pDDIs were identified in the patients of chest diseases unit. Furosemide (n=24, 11.8%) followed by salbutamol (n=21, 10.3%) and the furosemide-budesonide (n=5, 2.5%) combination were the most prevalent drugs which involved in pDDIs. These results indicate the importance of critical evaluation of the patient’s medication order in the hospital and the urgency of developing strategies to improve drug safety.