Ivermectin impact over gut microbiota diversity: A comprehensive and updated analysis from pre-clinical and clinical evaluations

The antiparasitic ivermectin (IVM) has been widely used in human and veterinary medicine since 1988, due to its effectiveness in combating various parasitic infections. Recently, this drug gained media attention due to its potential antiviral activity during the Covid-19 pandemic However, despite its proven ineffectiveness in treating the disease, its use increased significantly. Thus, concerns have arisen regarding the excessive use of IVM over the gut microbiota diversity, raising questions about possible gut-dysbiosis and health implications. Studies in various mammalian species have shown that oral administration of IVM can induce gut dysbiosis, whereas other administration routes do not exhibit this effect. This alteration in gut microbiota composition may potentially affect immune response. However, there are divergences between the studies, especially due to different administration protocols and animal species. Research on non-mammalian organisms, such as mosquito larvae and beetles, also indicates a potential dysbiotic effect related to the use of IVM or the reflection of this effect on species that live in the same environment of treated animals. However, the understanding of these effects and their implications for human and animal health is still limited, highlighting the urgent need for studies to elucidate the role of IVM in the gut microbiota and its impact on health. Ivermectin can induce bacterial gut dysbiosis. The use of ivermectin leads to gut dysbiosis in both mammals and non-mammals, resulting in alterations to the composition of bacterial phyla, as evidenced by studies in humans and animal models, including mice, rats, tigers, horses, deer, dogs, as well as non-mammals such as larvae and beetles. In contrast, non-oral administration in mammals did not significantly alter the gut microbiota, as observed in animal models of chinchillas and sea lions. • Oral ivermectin can modulate the mammal gut microbiota. • Ivermectin induces gut bacterial dysbiosis in non-mammalian organisms. • Non-oral ivermectin administration in mammals has limited effects on gut microbiota. • The systemic impacts of ivermectin-induced gut dysbiosis remain uncertain.