 | |
 Chemical structure of ethambutol (top) and photo of ethambutol crystals (bottom) | |
| Clinical data | |
|---|---|
| Trade names | Myambutol, Etibi,[1] Servambutol, others |
| Other names | (2S,2’S)-2,2’-(Ethane-1,2-diyldiimino)dibutan-1-ol[2] |
| AHFS/Drugs.com | Monograph |
| License data | |
| Routes of administration | By mouth |
| ATC code | |
| Legal status | |
| Legal status | |
| Pharmacokinetic data | |
| Protein binding | 20–30% |
| Metabolism | liver |
| Eliminationhalf-life | 3–4 hours |
| Identifiers | |
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| CAS Number |
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| PubChemCID | |
| DrugBank | |
| ChemSpider | |
| UNII | |
| KEGG | |
| ChEBI | |
| ChEMBL | |
| CompTox Dashboard(EPA) | |
| ECHA InfoCard | 100.000.737 |
| Chemical and physical data | |
| Formula | C10H24N2O2 |
| Molar mass | 204.314 g·mol−1 |
| 3D model (JSmol) | |
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Ethambutol (EMB,E) is a medication primarily used to treattuberculosis.[4] It is usually given in combination with othertuberculosis medications, such asisoniazid,rifampicin andpyrazinamide.[5] It may also be used to treatMycobacterium avium complex, andMycobacterium kansasii.[4] It istaken by mouth.[4]
Common side effects include problems with vision,joint pain,nausea,headaches, andfeeling tired.[4] Other side effects includeliver problems andallergic reactions.[4] It is not recommended in people withoptic neuritis, significantkidney problems, or under the age of five.[5] Use duringpregnancy orbreastfeeding has not been found to cause harm.[5][6] In the United States the FDA has raised concerns about eye issues in the baby if used during pregnancy.[4] Ethambutol is believed to work by interfering with the bacteria'smetabolism.[4]
Ethambutol was discovered in 1961.[7] It is on theWorld Health Organization'sList of Essential Medicines[8] and is available as ageneric medication.[1]
(S,S)-(+)-Ethambutol is powerful and selective antitubercular drug. It is a typical example of an old drug that was introduced for clinical use in itsunichiral form. Ethambutol contains two constitutionally symmetricalchiral centers in its structure and exists in threestereoisomeric forms, theenantiomeric pair (+)-(S,S)- and (−)-(R,R)-ethambutol, along with the achiral stereoisomer calledmeso-form. The (+)-(S,S)-enantiomer harbors the antitubercular activity. This enantiomer is 500 and 12 fold more potent than (−)-(R,R)-ethambutol and themeso-form respectively. On the other hand, all the three isomers are equipotent in terms of the major side-effect of the drug, optic neuritis.[9] Toxicity is associated to both dose and duration of treatment. Hence the use of (S,S)-enantiomer greatly improved the risk/benefit balance.[10][11]
Ethambutol is used along with other medications to treat a number of infections including:tuberculosis,Mycobacterium avium complex, andMycobacterium kansasii.[4]
Ethambutol isbacteriostatic against actively growing TB bacilli. It works by obstructing the formation ofcell wall.Mycolic acids attach to the 5'-hydroxyl groups ofD-arabinose residues ofarabinogalactan and form mycolyl-arabinogalactan-peptidoglycan complex in the cell wall. It disrupts arabinogalactan synthesis by inhibiting the enzymearabinosyl transferase. Disruption of the arabinogalactan synthesis inhibits the formation of this complex and leads to increased permeability of the cell wall.[citation needed]
It is well absorbed from thegastrointestinal tract and well distributed in body tissues and fluids. 50% is excreted unchanged in urine.
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