Product Information

Registration Status: Active

E-BUTOL TABLET 400mg is approved to be sold in Singapore with effective from 1988-04-29. It is marketed by BEACONS PHARMACEUTICALS PTE LTD, with the registration number of SIN00581P.

This product contains Ethambutol 400mg in the form of TABLET. It is approved for ORAL use.

This product is manufactured by BEACONS PHARMACEUTICALS PTE LTD in SINGAPORE.

It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.



An antitubercular agent that inhibits the transfer of mycolic acids into the cell wall of the tubercle bacillus. It may also inhibit the synthesis of spermidine in mycobacteria. The action is usually bactericidal, and the drug can penetrate human cell membranes to exert its lethal effect. (From Smith and Reynard, Textbook of Pharmacology, 1992, p863)


For use, as an adjunct, in the treatment of pulmonary tuberculosis.

Mechanism of Action

Ethambutol inhibits arabinosyl transferases which is involved in cell wall biosynthesis. By inhibiting this enzyme, the bacterial cell wall complex production is inhibited. This leads to an increase in cell wall permeability.


About 75% to 80% of an orally administered dose of ethambutol is absorbed from the gastrointestinal tract.
Hepatic. Up to 15% of administered drug is metabolized to inactive metabolites. The main path of metabolism appears to be an initial oxidation of the alcohol to an aldehydic intermediate, followed by conversion to a dicarboxylic acid.


The most commonly recognized toxic effect of ethambutol is optic neuropathy, which generally is considered uncommon and reversible in medical literature. Other side effects that have been observed are pruritus, joint pain, gastrointestinal upset, abdominal pain, malaise, headache, dizziness, mental confusion, disorientation, and possible hallucinations.

Active Ingredient/Synonyms

(+)-2,2'-(ethylenediimino)di-1-butanol | (+)-ethambutol | (+)-N,N'-bis(1-(hydroxymethyl)propyl)ethylenediamine | (+)-S,S-ethambutol | (2S,7S)-2,7-Diethyl-3,6-diazaoctane-1,8-diol | (S,S)-Ethambutol | EMB | Etambutol | Etambutolo | Ethambutol | Ethambutolum | S,S-Ethambutol | Ethambutol |

Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.


  1. Health Science Authority of Singapore - Reclassified POM
  2. Drugbank