An antibiotic with bacteriostatic, antimicrobial and antitubercular properties. Ethambutol interferes with the biosynthesis of arabinogalactan, a major polysaccharide of the mycobacterial cell wall. It inhibits the polymerization of cell wall arabinan of arabinogalactan and lipoarabinomannan by blocking arabinosyl transferases and induces the accumulation of D-arabinofuranosyl-P-decaprenol, an intermediate in arabinan biosynthesis. This results in halting bacterial growth.

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)

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.