anthelminthic

An anthelmintic is a drug used to treat infections caused by helminths, or parasitic worms. Helminths include nematodes (roundworms), cestodes (tapeworms), and trematodes (flukes). Anthelmintics may be used in humans or animals and are a central tool in controlling endemic worm infections. Treatments vary by parasite and can involve single-dose regimens, multi-dose courses, or combination therapy, alongside public health measures such as improved sanitation to prevent re-infection.

Drugs act through diverse mechanisms. Benzimidazoles such as albendazole and mebendazole disrupt parasite microtubule formation, impairing nutrient uptake. Praziquantel increases calcium influx, causing paralysis in cestodes and trematodes. Ivermectin binds to invertebrate nerve channels, producing paralysis in many nematodes. Pyrantel pamoate depolarizes neuromuscular transmission in intestinal nematodes. Niclosamide interferes with energy metabolism in tapeworms. Other agents have broader or complementary activity against specific worm groups.

Anthelmintics are grouped by spectrum and target. Some are broad-spectrum, effective against multiple worm types; others are species-specific. Most regimens are oral, but some infections use topical or parenteral forms. Dosing ranges from a single dose to several days or weeks, and some situations require combination therapy or procedures for parasite removal.

Safety and resistance considerations are important. While tolerability is generally favorable, side effects such as abdominal discomfort, nausea, or fever after parasite die-off can occur. Certain drugs are not recommended during early pregnancy or in liver disease. Resistance has emerged in veterinary use and is a concern for some human infections, underscoring the need for prudent use, surveillance, and integrated control measures alongside sanitation improvements.