Trematode infections, drugs

In addition to the above natural products, the ipecac alkaloid, emetine (6, chapter 15) and the antibiotic paromomycin (18, chapter 15), which are primarily used as antiprotozoal drugs, have also been found to be effective in the chemotherapy of trematode infections in humans. 

Although a number of salicylanihde anthelmintics have been developed, most of them find use in the treatment of cestode and trematode infections in domestic animals. Niclosamide (4) is the only drug which has been extensively used to cure cestode infections in human. 

This group comprises drugs mainly used for trematode infections such as e.g. schistosomiasis. Various plant extracts have been tested in Africa and Latin America with promising results, e.g. Phytolacca- dodecandra. L Her (Endod or soapberry) which contains saponins which kill the snails which act as vectors for the parasite. 

Answer D. Praziquantel is the drug of choice for treatment of all fluke (trematode) infections and most tapeworm (cestode) infections. Its antihelminthic action derives from an increase in membrane permeability to Ca, which results in contraction, followed by paralysis, of worm musculature. Mebendazole also has antihelminthic activity, hut it is restricted to the nematodes. The other drugs listed are antiprotozoals. 

Clinical use Mebendazole is a drag of choice for pinworm and whipworm infections. It is one of two drugs of choice (with pyrantel pamoate) for roundworm and for combined infections with ascarids and hookworm. Mebendazole can also be used as a backup drag in certain cestode and trematode infections. Less than 10% of the drag is absorbed systemi-cally after oral use, and this portion is metabolized rapidly. 

Praziquantel is effective in the treatment of schistosome infections of all species and most other trematode and cestode infections, including cysticercosis. The drug s safety and effectiveness as a single oral dose have also made it useful in mass treatment of several infections. 

The drug of choice for all species of Schistosoma, the most important trematode of humans, is praziquantel (Chapters 13 and 14, this volume). As would be expected this is also the drug of choice for the majority other species of fluke infecting humans (summarized in Table 12.3). A detailed review of the different... 

Worms are known as helminths and the majority is not parasitic. Classes of worms that parasitize man are round worms (nematodes) and flat worms (platyhelminths). The flat worms are divided into tapeworms (cestodes) and flukes (trematodes). Only a few human parasitic worms are common in the United Kingdom, for example threadworms and round worms. In tropical and subtropical parts of the world, where abundant water and high temperatures provide an optimal environment for the larvae and intermediate hosts, parasitic worms are common and widespread. Table 9.8 lists some parasitic worms that can infect man, their effect and drugs used to treat them. 

THERAPEUTIC USES Praziquantel is FDA approved for therapy of schistosomiasis and liver fluke infections, but also is used to treat infections with many other trematodes and cestodes. Praziquantel is the drug of choice for schistosomiasis caused by all Schistosoma species. Although dosage regimens vary, a single oral dose of 40 mg/kg or three doses of 20 mg/kg each, given 4-6 hours apart, generally produce cure rates of 70-95% and consistent reductions (>85%) in egg counts. Tablets of 600 mg are available. 

Identify the drugs of choice for treatment of common infections caused by nematodes, trematodes, and cestodes. 

Anthelmintic important drug for trematode (fluke) and cestode (tapeworm) infections. Increases membrane permeability to Ca causing muscle contraction followed by paralysis. Tox headache, dizziness, GI distress, fever potential abortifacient. 

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