Schistosomiasis (Bilharzia) Medication

Updated: Jul 24, 2017
  • Author: Shadab Hussain Ahmed, MD, AAHIVS, FACP, FIDSA; Chief Editor: Michael Stuart Bronze, MD  more...
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Medication

Medication Summary

The aim of chemotherapy is 2-fold. The first goal is to cure the disease or at least minimize morbidity. The second goal is to control transmission of the parasite in the endemic areas. Praziquantel and oxamniquine (no longer available in the United States) are used commonly, but praziquantel is the treatment of choice for all species of schistosomiasis. Clinical studies show that artemether, which is used as antimalarial treatment, is also active against all 3 major schistosome parasites (mainly schistosomula). [62]

In addition, the combination of artemether and praziquantel can kill schistosomula during the first 3 weeks of infection and is synergistic with praziquantel in killing adult worms. [66] The high efficacy of mefloquine-artesunate against S haematobium warrants further investigation. Individuals co-infected with Plasmodium and Schistosoma who are treated with a mefloquine-artesunate combination against malaria may experience a dual benefit: clearance of malaria parasitemia and reduction of schistosomiasis-related morbidity. [67]

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Anthelmintics

Class Summary

Parasite biochemical pathways are sufficiently different from the human host to allow selective interference by chemotherapeutic agents in relatively small doses.

Praziquantel (Biltricide)

Praziquantel is usually well tolerated. It is used for the treatment of individual patients and for mass community treatment programs. The drug's mechanism of action is complex; it induces ultrastructural changes resulting in increased permeability to calcium ions. Calcium ions accumulate in the parasite cytosol, leading to muscle contractions and ultimate paralysis of adult worms. The worm's tegument membrane (the natural covering of the worm body) is damaged, exposing the worm to the patient's immune response, which leads to worm death. The cure rate with praziquantel is 85% or greater. In persons not cured, the egg burden is markedly decreased.

Oxamniquine (Vansil)

Oxamniquine is no longer available in the United States. Its mechanism of action is complex. The drug is metabolized into an ester by schistosomes. It damages the tegument of male schistosome worms so that the patient's immune system is able to kill the organisms. It also stops female worms from producing eggs. Oxamniquine is effective only against S mansoni. The cure rate with the drug is 60-90%.

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