Drug repurposing: cost effectiveness and impact on emerging and neglected diseases

Historically, pressure on nature brought about by ever-increasing human pollution and technological advancement culminate in emergence and re- emergence of infectious and non-infectious diseases; necessitating medications and drug discovery and development. The emergence of resistantmicroorganisms and the emergence of new infections disease conditions necessitate the production of entirely new drugs or modification of the existing ones to increase their efficacy. The development of novel medications is a very long and expensive process. There is a significant decrease observed in the number of new drugs approved for clinical use in recent years showing inconsistency in the face of scientific advances and research and development investment. Regardless of high investment and enormous contributions, very few molecules showed promising results. However, finding novel indications for existing drugs can be a useful method of reducing the developmental cycle of drugs. Repositioning (also called repurposing) has been described as the practice of developing new therapeutic uses for drugs, abandoned or drugs in development process, other than the initially intended or approved uses, except for the circumstances in which the novel use is comparable to the original indication with dissimilar pharmacological targets. This review aimed at looking into some of the available methods in drug repurposing. Key words: Drug discovery; Drug repurposing; Machine learning; Neglected Tropical diseases; Orphan drugs