Ethionamide is an antibiotic used to treat tuberculosis. Specifically it is used, along with other antituberculosis medications, to treat active multidrug-resistant tuberculosis. It is no longer recommended for leprosy. It is taken by mouth.Ethionamide has a high rate of side effects. Common side effects include nausea, diarrhea, abdominal pain, and loss of appetite. Serious side effects may include liver inflammation and depression. It should not be used in people with significant liver problems. Use in pregnancy is not recommended as safety is unclear. Ethionamide is in the thioamides family of medications. It is believed to work by interfering with the use of mycolic acid.Ethionamide was discovered in 1956 and approved for medical use in the United States in 1965. It is on the World Health Organizations List of Essential Medicines. Medical uses
Ethionamide is used in combination with other antituberculosis agents as part of a second-line regimen for active tuberculosis.Ethionamide is well absorbed orally with or without food, but is often administered with food to improve tolerance. It crosses the blood brain barrier to achieve concentrations in the cerebral-spinal fluid equivalent to plasma.The antimicrobial spectrum of ethionamide includes M. tuberculosis, M. bovis and M. segmatis. It also is used rarely against infections with M. leprae and other nontuberculous mycobacteria such as M. avium and M. kansasii. While working in a similar manner to isoniazid, cross resistance is only seen in 13% of strains, since they are both prodrugs but activated by different pathways.
It boosts levels of isoniazid when taken together and can lead to increased rates of peripheral neuropathy and hepatotoxicity. When taken with cycloserine, seizures have been reported. High rates of hepatotoxicty have been reported when taken with rifampicin. The drugs labeling cautions against excessive alcohol ingestion as it may provoke a psychotic reaction. Mechanism of action
Ethionamide is a prodrug which is activated by the enzyme ethA, a mono-oxygenase in Mycobacterium tuberculosis, and then binds NAD+ to form an adduct which inhibits InhA in the same way as isoniazid. The mechanism of action is thought to be through disruption of mycolic acid.Expression of the ethA gene is controlled by ethR, a transcriptional repressor. It is thought that improving ethA expression will increase the efficacy of ethionamide and prompting interest by drug developers in EthR inhibitors as a co-drug. Other names
1314
2-ethylisothionicotinamide
amidazine
thioamide
iridocinIt is sold under the brand name Trecator by Wyeth Pharmaceuticals which was purchased by  Pfizer in 2009. References
External links
"Ethionamide". Drug Information Portal. U.S. National Library of Medicine. Ethionamide (PIM 224)