Anthelmintics

Anthelmintics are drugs used to treat infections with parasitic worms (helminths), including nematodes (roundworms), cestodes (tapeworms), and trematodes (flukes). They work by expelling the parasite from the host or by disabling or killing the parasite, allowing the host’s immune system to clear the infection. They are used in human medicine, veterinary medicine, and in public health programs aimed at controlling helminthiases.

Common drug classes include benzimidazoles such as albendazole and mebendazole, which inhibit microtubule formation in parasites; praziquantel, which increases calcium influx and disrupts membranes, making it effective against flukes and tapeworms; nicotinic agonists like pyrantel, which paralyze intestinal nematodes; and macrocyclic lactones such as ivermectin and moxidectin, which disrupt neuronal signaling in nematodes. Diethylcarbamazine is used against certain filarial infections. Nitazoxanide has activity against a range of helminths and some protozoa. In many settings, treatment choices depend on the parasite species, regional patterns of resistance, and patient factors.

Administration is usually oral, though some drugs are available in topical or injectable forms. Safety profiles vary by drug and pregnancy status, but adverse effects are typically mild and may relate to parasite die-off. Resistance to anthelmintics is a growing concern, particularly in agriculture and mass drug administration programs, underscoring the need for appropriate use, surveillance, and sometimes combination therapies.