Ethionamide

Absorption

Essentially completely absorbed following oral administration and not subjected to any appreciable first pass metabolism. Bioavailability approximately 100%.

Toxicity

Symptoms of overdose include convulsions, nausea, and vomiting.

Description

Ethionamide is an antimycobacterial compound that is active against M. tuberculosis (MICs = 0.3-1.25 μg/ml). It is activated via oxidation by flavin monooxygenase and inhibits the InhA enzyme involved in mycolic acid biosynthesis. Formulations containing ethionamide have been used in the second-line treatment of multi-drug resistant tuberculosis.

The Uses of Ethionamide

Ethionamide is used in antimicrobials and in potency assay of test compounds on M. tuberculosis.

Background

A second-line antitubercular agent that inhibits mycolic acid synthesis. It also may be used for treatment of leprosy. (From Smith and Reynard, Textbook of Pharmacology, 1992, p868)

Indications

For use in the treatment of pulmonary and extrapulmonary tuberculosis when other antitubercular drugs have failed.

What are the applications of Application

Ethionamide is a tuberculostatic antibacterial

Pharmacokinetics

Ethinamate is bacteriostatic against M. tuberculosis. In a study examining ethionamide resistance, ethionamide administered orally initially decreased the number of culturable Mycobacterium tuberculosis organisms from the lungs of H37Rv infected mice. Drug resistance developed with continued ethionamide monotherapy, but did not occur when mice received ethionamide in combination with streptomycin or isoniazid.

Metabolism

Hepatic and extensive. Metabolized to the active metabolite sulfoxide, and several inactive metabolites. The sulphoxide metabolite has been demonstrated to have antimicrobial activity against Mycobacterium tuberculosis.