Medication Summary
Praziquantel and triclabendazole are the two agents that the World Health Organization (WHO) and CDC recommend to treat paragonimiasis. Praziquantel is the most commonly used and has a cure rate of 80-90%
Antiparasitic agents
Class Summary
Triclabendazole was approved by the FDA in 2019 for fascioliasis after being available for many years from the CDC. The CDC recommends triclabendazole off-label for treatment of paragonimiasis.
Praziquantel (Biltricide)
Praziquantel increases cell membrane permeability in susceptible worms, resulting in loss of intracellular calcium, massive contractions, and paralysis of musculature. It produces vacuolization and disintegration of schistosome tegument, followed by attachment of phagocytes to the parasite and death.
Swallow the tablet whole with some liquid during meals. Keeping the tablet in the mouth may reveal bitter taste, which can produce nausea or vomiting.
Triclabendazole (Egaten)
Triclabendazole is an anthelmintic agent. It is approved for fascioliasis, but off-label use for paragonimiasis is supported by recommendations from the CDC. Its mechanism of action is not fully elucidated. Studies in vitro and/or in infected animals suggest that triclabendazole and its active metabolites (sulfoxide and sulfone) are absorbed by the tegument of the immature and mature worms, leading to a decrease of the resting membrane potential, inhibition of tubulin function, and inhibition of protein and enzyme synthesis.
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This micrograph depicts an egg from the trematode parasite Paragonimus westermani. Eggs range in size from 68-118 µm x 39-67 µm. They are yellow-brown and ovoidal or elongated, with a thick shell. They are often asymmetrical, with one end slightly flattened. At the large end, the operculum (ie, lid or covering) is visible. Photo courtesy of The Centers for Disease Control and Prevention.
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This is an illustration of the life cycle of Paragonimus westermani, one of the causal agents of paragonimiasis. Photo courtesy of The Centers for Disease Control and Prevention.
