Abstract: Drug-drug interactions (DDI) change dose-response relationships, and may result in low efficacy or high toxicity, which are important considerations especially in medical practice with multiple-drug therapies. Predicting clinically significant drug interactions during new drug development is an important part of benefit and risk assessment in drug development and review. This article summarizes the purpose and significance of drug interactions in new drug development, the main content and precautions of DDI studies in vivo and in vitro. Drug interaction studies on novel drug approvals for 2020 in the National Medical Products Administration (NMPA) and US Food and Drug Administration (USFDA) are examined, respectively. It aims to provide reference for DDI studies and regulatory reviews in new drug development in our country.

Key words: Drug-drug interactions (DDI), drug development, novel drug approvals, National Medical Products Administration, US Food and Drug Administration