Therapeutic and Formulation Advances of Ivermectin in Veterinary and Human Medicine

The treatment of parasitic infections has evolved in terms of effectiveness and the prevention of drug resistance. This is highlighted by the discovery of ivermectin (IVM), a macrocyclic lactone and broad-spectrum antiparasitic agent. IVM garnered scientific attention by presenting a therapeutic alternative in the field of veterinary medicine due to its control of multiple parasite species, including nematodes and soil-transmitted helminths. Shortly after its discovery, IVM was approved for human use by the World Health Organization (WHO) and United States Food and Drug Administration (FDA) for combating head lice, onchocerciasis, rosacea, scabies, and worm infestations within the gastrointestinal tract (GIT). In veterinary medicine, IVM is available in a range of formulations and can be administered via different routes (i.e., oral, topical, and parenteral), whereas for humans, IVM is only approved as a single oral dose and dermal cream. Establishing a comprehensive overview of IVM's applications in both human and veterinary medicine is necessary, particularly in light of its repurposing potential as a treatment for various conditions and emerging diseases. Given its primary application in veterinary medicine, there is a need to enhance the development of dosage forms suitable for human use. Therefore, this review details the discovery, mechanisms, and applications of IVM, while also examining the challenges of resistance, side-effects, and controversy surrounding its use, to ultimately emphasize the importance of targeted, optimized IVM delivery via tailored dosage form development in animals and humans as part of the One Health approach to interlink innovations across veterinary and human medicine fields.