Antihelmintika

Antihelmintika, or anthelmintics, are drugs used to treat infections with helminths, including nematodes (roundworms), cestodes (tapeworms) and trematodes (flukes). They are used in both human medicine and veterinary practice, with treatment choices guided by the parasite species, infection site, patient age, and local resistance patterns.

Major drug classes include benzimidazoles (example: albendazole, mebendazole), which disrupt parasite microtubule synthesis by binding beta-tubulin; macrocyclic lactones (ivermectin, moxidectin), which enhance chloride conductance leading to paralysis; praziquantel, which increases calcium influx causing rapid paralysis of cestodes and trematodes; and other agents such as pyrantel, niclosamide and nitazoxanide with varying spectra.

These drugs act through distinct mechanisms, ranging from inhibition of energy metabolism (niclosamide, nitazoxanide) to neuromuscular effects (pyrantel, macrocyclic lactones) or tegumental disruption (praziquantel). The result is impaired energy production, paralysis, detachment from tissues, or death of the parasite, with selective toxicity to the parasite relative to the host.

Antihelmintics vary in spectrum: some are broad-spectrum against multiple nematodes, others target specific groups such as cestodes or trematodes. They are generally administered orally, with dosing based on species and weight; adverse effects are usually mild, but can include GI symptoms, dizziness or hypersensitivity. Pregnancy and liver disease require caution and medical supervision.

Resistance to certain antihelmintics has emerged in animal parasites and is increasingly reported in some human infections, prompting rotation or combination therapy and ongoing surveillance. Proper diagnosis and adherence to guidelines are essential to minimize adverse effects and resistance development.