Chapter 10: Repurposing Approved Drugs to Block Highly Pathogenic Emerging Viruses

Except for influenza viruses, all other highly pathogenic viruses threatening worldwide public health lack a specific antiviral treatment. Besides traditional drug discovery approaches, repurposing of existing drugs can represent a convenient strategy to identify novel drugs and targets for antiviral therapeutic intervention. In this chapter, we describe the strategies that can be pursued to identify licensed drugs with repurposing potential as antivirals. Moreover, the most promising candidate drugs for the treatment of diseases caused by highly pathogenic emerging viruses are described, giving particular emphasis to drugs with broad-spectrum activity against unrelated viral pathogens, and drugs that are currently under clinical investigation in human trials for their repurposing as antiviral agents. Finally, we analyze what we have learned so far and the limitations of this popular approach of drug discovery as well as discuss how these could be overcome in the future to prompt the licensing of repurposed drugs as antivirals.