Category: catabolism
Parasites split into helminths (worms — nematodes, cestodes, trematodes) + protozoa (single-celled — Plasmodium, Trichomonas, Giardia, Entamoeba). Anthelmintic mechanisms exploit parasite-specific biology: ivermectin opens glutamate-gated chloride channels (insect/nematode-specific) → paralysis (avermectin class); benzimidazoles (albendazole, mebendazole) bind parasite β-tubulin selectively (low mammalian affinity) → microtubule disruption; praziquantel disrupts cestode/trematode tegument calcium homeostasis; pyrantel (covered as pk_unauthored local-acting) depolarizes neuromuscular junction. Antiprotozoals: artemisinin generates parasite-specific peroxide radicals in heme-rich Plasmodium digestive vacuole; hydroxychloroquine concentrates in the same acidic vacuole → heme polymerization block; quinine — historical cinchona alkaloid still used for chloroquine-resistant malaria; nitazoxanide blocks pyruvate-ferredoxin oxidoreductase (PFOR, anaerobe-specific).