Medication Summary
Benzimidazoles are effective for the treatment of intestinal ascariasis, although some authors recommend against their use in the first year of life and during pregnancy due to their teratogenic effects in animal studies. The most commonly recommended agents are albendazole and mebendazole. Ivermectin and pyrantel pamoate are alternatives, the latter having been suggested for pregnant patients in whom benzimidazoles are contraindicated. An anthelmintic agent from China, tribendimidine (at a dose of 300 mg), has been shown to be as efficacious as albendazole. [20, 21]
Anthelmintics
Class Summary
Parasite biochemical pathways are sufficiently different from the human host to allow selective interference by chemotherapeutic agents in relatively small doses.
Albendazole (Albenza)
Decreases ATP production in worm, causing energy depletion, immobilization, and finally death.
Mebendazole (Vermox)
Causes worm death by selectively and irreversibly blocking uptake of glucose and other nutrients in susceptible adult intestine where helminths dwell.
Piperazine citrate
Recommend for GI or biliary obstruction secondary to ascariasis; causes flaccid paralysis of the helminth by blocking response to worm muscle to acetylcholine.
Pyrantel pamoate (Antiminth)
Depolarizing neuromuscular blocking agent; inhibits cholinesterases, resulting in spastic paralysis of worm.
Ivermectin (Stromectol)
Binds selectively with glutamate-gated chloride ion channels in invertebrate nerve and muscle cells, causing cell death.
Levamisole (Ergamisol)
May inhibit worm copulation via agonism of L-subtype nicotinic acetylcholine receptors in male nematode muscles.
-
Adult Ascaris lumbricoides.
-
Life cycle of Ascaris lumbricoides.
-
Ascaris lumbricoides egg.
-
Adult Ascaris lumbricoides in biliary system.
-
The roundworm Ascaris lumbricoides causes ascariasis. Worms can reach 10-30 cm in length. Clinical disease results from effects of pulmonary larval migration, intestinal obstruction, or migration through the biliary tree.
-
Ascaris lumbricoides egg in feces (formalin-ethyl acetate sedimentation method).
-
Endoscopic retrograde cholangiogram shows long, linear, filling defect in common bile duct. Image courtesy of Medscape.com.
