Drug Groups

approved

Description

2-Substituted benzimidazole first introduced in 1962. It is active against a variety of nematodes and is the drug of choice for strongyloidiasis. It has CNS side effects and hepatototoxic potential. (From Smith and Reynard, Textbook of Pharmacology, 1992, p919)

Indication

For the treatment of strongyloidiasis (threadworm), cutaneous larva migrans (creeping eruption), visceral larva migrans, and trichinosis.

Pharmacology

Thiabendazole is a fungicide and parasiticide. Thiabendazole is also a chelating agent, which means that it is used medicinally to bind metals in cases of metal poisoning, such as lead poisoning, mercury poisoning or antimony poisoning. Thiabendazole is vermicidal and/or vermifugal against Ascaris lumbricoides ("common roundworm"), Strongyloides stercoralis (threadworm), Necator americanus, Ancylostoma duodenale (hookworm), Trichuris trichiura (whipworm), Ancylostoma braziliense (dog and cat hookworm), Toxocara canis, Toxocara cati (ascarids), and Enterobius vermicularis (pinworm). Thiabendazole also suppresses egg and/or larval production and may inhibit the subsequent development of those eggs or larvae which are passed in the feces.

Toxicity

Overdosage may be associated with transient disturbances of vision and psychic alterations. The oral LD 50 is 3.6 g/kg, 3.1 g/kg and 3.8 g/kg in the mouse, rat, and rabbit respectively.

Affected Organisms

Biotransformation

Hepatic. Metabolized almost completely to the 5-hydroxy form which appears in the urine as glucuronide or sulfate conjugates.

Absorption

Rapidly absorbed and peak plasma concentration is reached within 1 to 2 hours after the oral administration of a suspension. Some systemic absorption may occur from topical preparations applied to the skin.

Half Life

The half-life for thiabendazole in both normal and anephric patients is 1.2 hours (range 0.9 to 2 hours). The half-life for the 5-hydroxythiabendazole metabolite in both normal and anephric patients is 1.7 hours (range 1.4 to 2 hours).

Elimination

It is metabolized almost completely to the 5-hydroxy form which appears in the urine as glucuronide or sulfate conjugates.

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