Medications that kill, paralyze or inhibit parasites living on or inside a host【365791507805797†L69-L72】
Explanation
Antiparasitic agents are used to treat infections caused by parasitic organisms. Parasites include ectoparasites such as lice, mites and ticks, endoparasitic protozoa that invade tissues or blood, and multicellular helminths that inhabit the gastrointestinal tract or other organs【365791507805797†L86-L99】. These organisms obtain nutrients from their host and can cause malnutrition, anaemia, organ damage or immune responses. Antiparasitic drugs work by targeting processes essential to the parasite but absent or less critical in the host. Antihelminthic compounds disrupt microtubule polymerisation, inhibit energy metabolism or paralyse neuromuscular systems, leading to expulsion of worms. Antiprotozoal agents interfere with nucleic acid synthesis, folate metabolism or anaerobic energy production. Ectoparasiticides penetrate the exoskeleton of arthropods to cause neuronal hyperexcitation and death. Antiparasitic drugs are grouped into antiprotozoal agents, antihelminthic agents and ectoparasiticides【365791507805797†L143-L154】. Many antiparasitics are selectively toxic, but misuse or subtherapeutic dosing can allow parasites to survive and develop resistance. Because parasites vary widely in biology, effective treatment depends on accurate identification and may require combination therapy or sequential regimens.
Drug classes and uses
Antihelminthic drugs include benzimidazoles such as albendazole and mebendazole for soil‑transmitted roundworms and hookworms, pyrantel pamoate for pinworms, praziquantel for schistosomiasis and tapeworms, and ivermectin for onchocerciasis and strongyloidiasis. Antiprotozoal agents include nitroimidazoles like metronidazole for amoebiasis and giardiasis, antimalarials such as chloroquine and atovaquone–proguanil for malaria, and pentamidine or suramin for trypanosomiasis. Ectoparasiticides such as permethrin and topical ivermectin treat scabies and pediculosis. Some agents have broad spectrum activity, while others are species‑specific. Public health programmes often administer antiparasitics to large populations to control neglected tropical diseases. Rational prescribing, appropriate dosing and monitoring are essential to prevent reinfection and slow the emergence of resistant parasites.
Antiparasitics remain indispensable for controlling parasitic diseases, but their benefits depend on accurate diagnosis and judicious use.
Related Terms: Helminths, Protozoa, Anthelmintic, Antiprotozoal, Antimicrobials