Sharing is Caring: Drug Repurposing among Leading Diseases

The process of drug development is time-consuming and resource-intensive, but drug repurposing offers an alternative by using already approved drugs to treat different diseases. Drug repurposing candidates can be identified through computational and experimental approaches, which are often combined. Traditionally, drug repurposing is considered when developing a custom drug is not feasible, but recent findings regarding the cross-talk between cellular mechanisms and pathways that are altered among disease states suggest that multipurpose drugs may be the key to simultaneously treating multiple diseases. This chapter reviews published reports on drug repurposing for five of the most threatening diseases to human health today: Alzheimer's disease, arthritis, diabetes mellitus, cancer, and COVID-19, highlighting promising candidates, challenges, and potential future directions for research.