This study aims to comprehensively identify and categorize drug-related problems in in-patients admitted to a tertiary care hospital. The primary objectives include identifying and classifying medication errors, detecting adverse drug events, and identifying and classifying drug-drug interactions. The secondary objectives involve observing the outcomes of medication errors, assessing the causality of adverse drug reactions, and observing the outcomes of drug-drug interactions. Through this research, a deeper understanding of drug-related issues and their consequences will be gained, ultimately leading to improved patient safety and healthcare outcomes.