Antiparasitics

Antiparasitics are drugs or compounds used to treat infections caused by parasites, including protozoa, helminths (worms), and ectoparasites such as lice and mites. They are used in human medicine and veterinary medicine and encompass several broad classes, including antiprotozoals, anthelmintics, and pediculicides or other ectoparasiticides. Common human antiparasitics include metronidazole and tinidazole for anaerobic protozoa, nitazoxanide, antimalarials such as chloroquine and artemisinin-based therapies, benzimidazole derivatives like albendazole and mebendazole, ivermectin, praziquantel, diethylcarbamazine, pyrantel pamoate, and topical agents such as permethrin and malathion for ectoparasites.

Mechanisms of action vary by parasite type and drug class. Some drugs inhibit nucleic acid synthesis or energy metabolism in the parasite, others disrupt microtubule formation or neuromuscular signaling, and still others damage the parasite’s tegument or membranes. Efficacy depends on the species and life stage targeted, and resistance is an increasing concern in many parasite groups. Host toxicity and drug interactions are important considerations, particularly in pregnancy, in children, and in regions with overlapping infectious diseases.

Usage and public health considerations often extend beyond individual treatment. Antiparasitics are used in mass drug administration programs in endemic areas, alongside vector control, improved sanitation, and health education to reduce transmission. Ongoing research seeks broader spectra, improved safety and dosing, and strategies to mitigate emerging resistance, reflecting the diverse and evolving field of antiparasitic therapy in both human and veterinary medicine.