The aim of this study was to assess the drug utilization pattern of parenteral antibiotics in medicine units. A prospective and observational study was done on patients admitted in medicine indoor. Information regarding patient demographic details, patient medication history, and reason for admission, medication details and lab investigations. Patient drug therapy details such as diagnosis, clinical condition, therapy details such as name of the antibiotics, dose, route, frequency, duration of treatment were collected and recorded in performa. Rationality was assessed by using standard guidelines, micromedex, and NFI. Drug interactions and ADR were assessed  by using standard text books like stockley drug interactions text book 8th edition. And Micromedex. A 310 patients received parenteral antibiotics in the medicine units was found to be 12.54%. amongst incidence of use of parenteral antibiotics was highest in medicine unit B (42.12%). Cephalosporins (64.54%) were the most frequently prescribed class of  parenteral antibiotics. ceftriaxone (53.63%) was the frequently used antibiotic. Cefriaxone is commonly prescribed for viral fever. 43% of major drug interactions were identified. It is essential that appropriate guidelines on the use of parenteral antibiotics are implemented to prevent irrational use of antibiotics.