アルベンダゾール

外観

白色～ほとんど白色粉末～結晶

用途

アルベンダゾール（Albendazole）は、様々な寄生虫感染症を治療可能な医薬品である。商品名エスカゾール。日本で包虫症の治療薬として承認されているほか、海外ではジアルジア症、鞭虫症、フィラリア、神経嚢虫症（英語版）、蟯虫症（英語版）、回虫症等の治療に用いられる。 ベンゾイミダゾール系の広スペクトル駆虫薬に分類される。経口薬である。

効能

駆虫薬

商品名

エスカゾール (グラクソ・スミスクライン)

化学的特性

Albendazole occurs as a white to faintly yellowish powder. It is practically insoluble in water and alcohol, very slightly soluble in ether and dichloromethane, but freely soluble in anhydrous formic acid.

使用

Albendazole is a derivative of benzimidazole, is a drug with a broad antihelmintic spectrum. It exhibits an antihelmintic effect against sensitive cestodes and nematodes by blocking the process of glucose uptake by the parasites, which is expressed in the depletion of glycogen reserves and subsequent reduction in the level of adenosintriphophate. As a result, the parasite stops moving and dies. It is used upon infection of Acaris lumbricoides, Ancylostoma duodenale, Necator americanus, Enterobius vermicularis, and Trichuris trichiura. Synonyms of this drug are SKF 62979 and others.

適応症

Albendazole appears to cause cytoplasmic microtubular degeneration, which in turn impairs vital cellular processes and leads to parasite death.There is some evidence that the drug also inhibits helminth-specific ATP generation by fumarate reductase.

抗菌性

Albendazole is active against trichostrongyles and exhibits useful activity against tissue-dwelling larvae of Trichinella spiralis, larvae of animal hookworms (causing cutaneous larva migrans) and microfilariae of various filarial species. It also exhibits some activity against cysticercosis and hydatid stages of Echinococcus granulosus and Echinococcus multilocularis. It has been successfully used in infections with the protozoon Giardia lamblia and for microsporidiosis.

一般的な説明

Albendazole occurs as a white crystalline powder that isvirtually insoluble in water. The oral absorption of albendazoleis enhanced by a fatty meal. The drug undergoes rapidand extensive first-pass metabolism to the sulfoxide, whichis the active form in plasma. The elimination half-life ofthe sulfoxide ranges from 10 to 15 hours. Considerable biliaryexcretion and enterohepatic recycling of albendazolesulfoxide occurs. Albendazole is generally well toleratedin single-dose therapy for intestinal nematodes. The highdose,prolonged therapy required for clonorchiasis orechinococcal disease therapy can result in adverse effectssuch as bone marrow depression, elevation of hepatic enzymes,and alopecia.

作用機序

Albendazole is given orally and is poorly and variably absorbed (5%) because of its poor water solubility. Oral bioavailability is increased as much as five times when the drug is given with a fatty meal instead of on an empty stomach. Concurrent treatment with corticosteroids increases plasma concentrations of albendazole. The drug is rapidly metabolized in the liver to an active sulfoxide metabolite.The half life of the metabolites is 8 to 12 hours.

薬物動態学

Albendazole is better absorbed after oral absorption than other benzimidazole carbamates. It is extensively metabolized to the anthelmintically active albendazole sulfoxide, producing plasma concentrations of the metabolite of about 1.3 mg/L 2–5 h after a 400 mg oral dose. The half-life is about 8 h and the major route of excretion is via the bile. Plasma protein binding of the sulfoxide is around 70%.

臨床応用

Albendazole has a broad spectrum of activity against intestinal nematodes and cestodes, as well as the liver flukes Opisthorchis sinensis, Opisthorchis viverrini, and Clonorchis sinensis. It also has been used successfully against Giardia lamblia. It is widely used throughout the world for the treatment of intestinalnematode infection. It is effective as a single-dose treatmentfor ascariasis, New and Old World hookworm infections,and trichuriasis. Multiple-dose therapy with albendazole caneradicate pinworm, threadworm, capillariasis, clonorchiasis,and hydatid disease. The effectiveness of albendazole againsttapeworms (cestodes) is generally more variable and lessimpressive. It also is effective in treating cerebral and spinal neurocysticercosis, particularly when given with dexamethasone.Albendazole is recommended for treatment of gnathostomiasis.

副作用

Various mild intestinal and other upsets usually resolve without treatment. With extended use, as for larval tapeworm infections, hepatic abnormalities or leukopenia may require discontinuation of treatment. In rare cases granulocytopenia, pancytopenia, agranulocytosis or thrombocytopenia may occur. It should not be given during pregnancy since it may cause fetal harm; women should be cautioned against becoming pregnant within a month of completing treatment.