Chapter 12 Antiparasitic Drugs

Chapter 35 Treatment of Infections III Antifungal and Antiparasitic Drugs... 

In contrast to the information available on carbohydrate and energy metabolism in parasites, relatively little is known about the fate of xenobiotics, including clinically used antiparasitic drugs. This chapter deals primarily with xenobiotic metabolism in helminths, although where available, information on the fate of foreign compounds in protozoan parasites is also included. 

Following an introduction to therapeutic strategies and commonly encountered microbes, this chapter discusses antibacterial, antiviral, antifungal, and antiparasitic drugs. 

Some antiparasitic drugs, notably the macrocyclic lactones, have already been addressed in Chapter 6. This chapter will examine the toxic effects of other compounds that are widely used, or have been used, as antiparasitic drugs in animals. In Europe and elsewhere, the main anthelmintic drugs are the benzimidazoles and levamisole. The major benzimidazole drugs are thiabendazole, albendazole, fenbendazole, flubendazole, mebendazole, oxfendazole, oxiben-dazole, triclabendazole and albendazole sulphoxide (ricobendazole, albendazole oxide). Febantel and netobimin are two prodrugs that in vivo are converted to fenbendazole and albendazole, respectively. Levamisole is the levo ( ) isomer of (dextro isomers. Tetramisole has been superseded by levamisole. These and some other antiparasitic drugs are discussed in this chapter. 

The polyketides are a large family of bio synthetically related NPs, some of which have very great pharmaceutical value (polyketide sales total about 10 billion annually, see also Chapter 7). Some antibiotics (erythromycin, monensin, rifamycin), immunosuppressants (rapamycin), antifungal substances (amphotericin), antiparasitic (aver-mectin) and anticancer drugs (doxorubicin) are polyketides. The term polyketide refers to the fact that the basic carbon skeleton is not a simple hydrocarbon chain as in the case of fatty acids but is a series of linked keto groups in sequence (Figure 3.6). The first phase of this pathway, the generation of carbon skeleton diversification. 

Katzung PHARMACOLOGY, 9e > Section VIII. Chemotherapeutic Drugs > Chapter 52. Basic Principles of Antiparasitic Chemotherapy > ... 

Because of its analogy to PPi and an ability to chelate metals, the BP structure has served as a pharmacophore for drug design in various areas. In addition, as detailed in Chapter I—1, "...in some cases a new clinical activity observed for an old drug is sufficiently potent and interesting to justify the immediate use of the drug in the new indication... . Some of the cases that follow fall into this class, and include especially antiparasitic, anti-arthritic, and antirestenosis applications. 

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