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Ethambutol substance photo.jpg
Ethambutol ball-and-stick.png
Other names
ATC code J04AK02
74-55-5 YesY
ChemSpider 13433 YesY
DrugBank DB00330 YesY
EC number 200-810-26
Jmol-3D images Image
KEGG D07925 YesY
MeSH Ethambutol
PubChem 14052
UNII 8G167061QZ YesY
Molar mass 204.31 g·mol−1
Appearance White crystals
Odor Odourless
log P −0.291
Metabolism Hepatic
3–4 hours
Protein binding 20–30%
Excretion Renal
Related compounds
Related compounds
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Ethambutol (commonly abbreviated EMB or simply E) is a bacteriostatic antimycobacterial drug prescribed to treat tuberculosis.[2] It is usually given in combination with other tuberculosis drugs, such as isoniazid, rifampicin and pyrazinamide.

Ethambutol is used along with other medications to treat a number of infections, including tuberculosis, Mycobacterium avium complex, and Mycobacterium kansasii.[3]

It can cause problems with vision, liver problems and allergies among other side effects.[3] It is pregnancy category C in the United States due to concerns with eye issues and category A in Australia meaning that they did not find evidence of harm after being taken by many pregnant women.[3][4] It is reasonable to use during breast feeding if required.[3]

It is sold under the trade names Myambutol and Servambutol. It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system.[5]

Medical uses[edit]

Ethambutol is used along with other medications to treat a number of infections including: tuberculosis, Mycobacterium avium complex, and Mycobacterium kansasii.[3]

Adverse effects[edit]

Mechanism of action[edit]

Ethambutol is bacteriostatic against actively growing TB bacilli. It works by obstructing the formation of cell wall. Mycolic acids attach to the 5'-hydroxyl groups of D-arabinose residues of arabinogalactan and form mycolyl-arabinogalactan-peptidoglycan complex in the cell wall. It disrupts arabinogalactan synthesis by inhibiting the enzyme arabinosyl transferase. Disruption of the arabinogalactan synthesis inhibits the formation of this complex and leads to increased permeability of the cell wall.


It is well absorbed from the gastrointestinal tract and well distributed in body tissues and fluids. 50% is excreted unchanged in urine.


  1. ^ "ethambutol (CHEBI:4877)". Chemical Entities of Biological Interest. UK: European Bioinformatics Institute. 18 August 2010. Main. Retrieved 26 April 2012. 
  2. ^ Yendapally R, Lee RE (March 2008). "Design, synthesis, and evaluation of novel ethambutol analogues". Bioorg. Med. Chem. Lett. 18 (5): 1607–11. doi:10.1016/j.bmcl.2008.01.065. PMC 2276401. PMID 18242089. 
  3. ^ a b c d e "Ethambutol Hydrochloride". The American Society of Health-System Pharmacists. Retrieved 24 April 2014. 
  4. ^ "Prescribing medicines in pregnancy database". Australian Government. 3 March 2014. Retrieved 22 April 2014. 
  5. ^ "WHO Model List of Essential Medicines" (PDF). World Health Organization. October 2013. Retrieved 22 April 2014. 
  6. ^ Lim SA (April 2006). "Ethambutol-associated optic neuropathy". Ann. Acad. Med. Singap. 35 (4): 274–8. PMID 16710500. 

External links[edit]