Drug Repurposing in Parasitology: New Uses for Old Drugs to Be Used Through the Host-Parasite Interface

Drug repurposing in parasitology gives existing medications new applications, such as using antibiotics for malaria, antimalarials for worms, and antifungals/cancer drugs for protozoa. This strategy saves time and money by passing early-stage safety testing for established human compounds. Although advances in genomics and proteomics have greatly expanded our understanding of parasite biology and facilitated the identification of potential therapeutic targets, they have translated into relatively few new antiparasitic drugs. This limitation highlights the need for alternative strategies such as drug repurposing. The basic biology of the host-parasite interface has not been thoroughly investigated despite its importance. The multifaceted immune-endocrine interplay may also help clarify the frequently inconsistent observations associated with host age and sex during infections, while providing insights that extend beyond current parasite management approaches. This review summarizes the potential uses and applications of old drugs as antiparasites, including, for example, the use of hormone agonists and antagonists and hormone analogues, while also discussing other drugs that have been isolated from natural products that are not used in the field.