Repurposing of Serotonin Pathway Influencing Drugs for Potential Cancer Therapy and Antimicrobial Functions

The conventional methods for the discovery and development of new drugs are a time-consuming and complex process that expands over several stages and decades. The repurposing of existing drugs for newer roles offers time and cost-saving benefits. Serotonin receptors are the means by which serotonin performs a variety of functions in the human body and several pharmacological classes of drugs, such as antidepressants, sedatives, antipsychotics, and migraine medications, can target the serotonin system. Many of these psychotropic drugs show antimicrobial functions. Studies have connected serotonin to the proliferation of cancer cells, and the serotonin pathway has been recognized as a potential target for cancer treatment. This chapter provides an overview of the literature on the relationship between serotonin (5-HT) and the immune system, and, sheds light on the anticancer and antimicrobial properties of some serotonin-pathway influencing drugs which can add to the understanding of the repurposing of these classes of drugs.