Helminths agents

The anti-helminthic agent levamisole has im-munostimulant properties. It increases chemotaxis and phagocytosis of macrophages and polymorphonuclear leukocytes and stimulates lymphocytes function. It has proved to be effective in treating RA. Its most common adverse effect is the occurrence of rashes. 

The second streptomycete genome completed has revealed 33 CYPs comprising 0.4% of genes. This industrial microorganism is important for the production of avermectin, an anti-helminthic agent. We have cataloged the S. avermitilis... 

Over the last several years, substantial progress in the discovery and development of anthelmintic dmgs has been made. Effective agents are available for most human gastrointestinal infections (Table 1) however, dmgs that are effective in treating the extraintestinal complications of many helminthic infections are still needed. 

The final reduction product of pyrazine, piperazine (89), is a stable compound which behaves as a typical diamine. It has found extensive use in medicinal chemistry as a linking agent and as a medicine in its own right for the treatment of helminths both in human and veterinary medicine. 

In many instances, the unaided immune response to such infections can be inadequate, leading to prolonged and/or serious illness. Examples include the malaria and tuberculosis agents, the HIV virus (which has infected at least 14 million people worldwide), leishmaniasis (caused by the protozoan Leishmania, from which 12 million people suffer) and schistosomiasis, (caused by the Schistoma mansoni helminth, which currently infects approximately 250 million people worldwide). 

Combating infectious diseases (viral, protozoal, fungal, bacterial, helminthic) Anti-cancer agent Alleviating allergic reactions Vaccine adjuvant... 

Mechanism of Action An anthelmintic agent that inhibits helminth-specific mitochondrial fumarate reductase. Therapeutic Effect Suppresses parasite production. Pharmacokinetics Rapidly and well absorbed from the gastrointestinal (Gl) tract. Rapidly metabolized in liver. Primarily excreted in urine partially eliminated in feces. Half4ife 1 2 hr... 

Although any microbe that infects a human (virus, bacteria, fungus, etc.) could theoretically be considered to be a parasite, the term parasite tends to be reserved for three types of infectious agents protozoa, helminths, and arthropods. These may be subdivided as follows ... 

Because of the importance of malaria, antiparasitic drugs are sometimes divided into two classes antiparasitic agents for protozoans, especially malaria, and antiparasitic agents for helminthic infestations. Each of these classes will be examined separately. 

A variety of structurally diverse compounds is used to eradicate or at least reduce the numbers of helminthic parasites in the intestinal tract or tissues of the body. The search for antihelminthics has been somewhat less systematic than for other microbial pathogens. Most of these agents were discovered by traditional screening programs their mechanisms of action at a molecular level are frequently unknown. 

Anthelmintic agents are used to eradicate (either kill or expel) the infesting helminths. 

Hunter, M.M. and McKay, D.M. (2004) Review article helminths as therapeutic agents for inflammatory bowel disease. Alimentary Pharmacology and Therapeutics 19, 1 67-1 77. 

Clinical Use. Paromomycin (Humatin) is an aminoglycoside antibacterial (see Chapter 33) that is used primarily to treat mild to moderate intestinal infections (amebiasis).51 This drug may also be used as an adjunct to other amebicides during the treatment of more severe protozoal infections. Paromomycin is also effective against some bacteria and tapeworms, and may be used as a secondary agent in certain bacterial or helminthic infections. This drug is administered orally. 

Some of the common anthelmintics used to kill the basic types of worms in humans are listed in Table 35-5. These agents are often very effective a single oral dose is usually sufficient to selectively destroy the parasite. Brief descriptions of the basic pharmacologic effects and possible adverse effects of the primary anthelmintic agents are presented below. Several authors have also extensively reviewed the pharmacologic treatment of helminthic infections.36,41,52,58,66... 

Anthelmintic agents used against worms and flukes (hence the name -helminths include liver flukes). 

In its general scientific sense, the term "parasite" includes all of the known infectious agents such as viruses, bacteria, fungi, protozoa, and helminths. In this and the two following chapters, the term is used in a restricted sense to denote the protozoa and helminths. It has been estimated that 3 billion (3 x 109) humans suffer from parasitic infections, plus a much greater number of domestic and wild animals. Although these diseases constitute the most widespread human health problem in the world today, they have for various reasons also been the most neglected. 

Benzimidazoles include albendazole, mebendazole and thiabendazole and constitute a major class of broad-spectrum anthelmintics. They work through an effect on helminth microtubular function, with considerable selectivity in this respect for worms as compared to humans. Mebendazole is much used, and is usually the drug of choice, and is relatively free of side-effects. Albendazole is a more recent agent that is better absorbed. These agents can be used for most worm infections, but not for flukes. 

General - A compendium of chemotherapeutic agents for parasitic protozoa and helminths of dogs and cats was published. Host-parasite relationships were reviewed.2 The proceedings of an international conference on chemotherapeutic agents for parasitic diseases appeared.3 Nucleoside analogs as antiparasitic agents were reviewed.4... 

It is a newly discovered intestinal helminth infection of man found in Latin America. The causative agents of the disease, Angiostrongylus costaricensis and A. can-tonensis, produce tumor-like lesions in the colon. Chemotherapy is usually not very satisfactory. Sometimes surgical intervention may be required. 

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