++
Helminths (worms) are multicellular parasites; they infect very large numbers of humans and cause a broad range of diseases.
Antihelminthic drugs have diverse chemical structures, mechanisms of action, and properties. Many act against specific parasites, and few are devoid of significant toxicity to host cells. In addition to the direct toxicity of the drugs, reactions to dead and dying parasites may cause serious toxicity in patients. In the text that follows, the drugs are divided into three groups on the basis of the type of helminth primarily affected (nematodes, trematodes, and cestodes). The drugs of choice and alternative agents for selected important helminthic infections are listed in Table 53–1.
++
+++
DRUGS THAT ACT AGAINST NEMATODES
++
The medically important intestinal nematodes responsive to drug therapy include Enterobius vermicularis (pinworm), Trichuris trichiura (whipworm), Ascaris lumbricoides (roundworm), Ancylostoma and Necator species (hookworms), and Strongyloides stercoralis (threadworm). More than 1 billion persons worldwide are estimated to be infected by intestinal nematodes. Pinworm infections are common throughout the United States, and hookworm and threadworm are endemic in the southern United States. Tissue nematodes responsive to drug therapy include Ancylostoma species, which cause cutaneous larva migrans. Species of Dracunculus, Onchocerca, Toxocara, and Wuchereria bancrofti (the cause of filariasis) are responsive to drug treatment. The number of persons worldwide estimated to be infected by tissue nematodes exceeds 0.5 billion.
++
The action of albendazole is thought to involve inhibition of microtubule assembly. The drug is larvicidal ...