Snapshot A 45-year-old man presents to the urgent care clinic with a skin rash, diarrhea, nausea, vomiting, and cough. He has a medical history notable for diabetes mellitus and hypertension. He recently visited his family’s farm in the countryside and walked around without shoes. He is asked to give a stool sample, and analysis of the sample showed rhabditiform larvae on microscopy but no eggs. He is started on an anti-helminthic medication. (Strongyloides infection) Introduction Drugs pyrantel pamoate ivermectin mebendazole praziquantel diethylcarbamazine niridazole Clinical use helminths cestodes (tapeworms) trematodes (flukes) nematodes (roundworms) Anti-Helminth Medications Drug Mechanism of Action Adverse Effects Helminth Pyrantel pamoate Neuromuscular blocking agent, causing depolarization Gastrointestinal upset Headaches Nematodes Enterobius Ancylostoma Necator Ivermectin Binds to glutamate-gated chloride channels, causing hyperpolarization Skin pruritus Nematodes Onchocerca (Rivermectin) Strongyloides Bendazole Inhibits tubulin polymerization, interfering with microtubule formation Gastrointestinal upset Stevens-Johnson syndrome Mebendazole nematodes Enterobius Ascaris Toxocara Trichuris Trichinella Strongyloides Ancylostoma Necator Albendazole cestodes Taenia Echinococcus Praziquantel Increases cell membrane permeability of calcium and causes paralysis in the helminth Gastrointestinal upset Dizziness Cestodes Taenia Diphyllobothrium Trematodes Schistosoma Clonorchis Paragonimus Diethylcarbamazine Inhibits arachidonic acid metabolism, making the helminth more susceptible to the host's innate immune system Skin pruritus Facial swelling Headaches Nematodes Wucheria Loa loa Niridazole Inhibits oogenesis and spermatogenesis Central nervous system toxicity Nematode Dracunculus