Pretomanid

Pretomanid is a prodrug which is metabolically activated by a nitroreductase enzyme, known as Ddn, producing various active metabolites that are responsible for its other therapeutic actions, particularly the induction of nitric oxide. The nitroreductase enzyme which activates pretomanid is deazaflavin dependent and relies on reduced cofactor F420. Reduction of F420 occurs via the enzyme glucose-6-phosphate dehydrogenase. Reduction of pretomanid's imidazole ring at the C-3 position causes the formation of the metabolites, which include a des-nitro derivative. The formation of this derivative leads to increased levels of nitric oxide, leading to bactericidal activities under anaerobic conditions via its action as a bacterial respiratory poison. Bactericidal activity against anaerobes is reported to be associated with a shortened duration of antibiotic treatment.

Pretomanid exerts aerobic bactericidal effects through its inhibitory actions on bacterial cell wall mycolic acid biosynthesis. This allows for the killing of actively replicating Mycobacterium tuberculosis bacteria, resulting in the treatment of active tuberculosis infection. The molecular mechanism of the above bactericidal effects is poorly understood at this time, but may involve effects exerted on various genes that affect the cell wall, including the fasI and fasII as well as the efpA and iniBAC operons. Other possible targets include the genes of the cyd operon. The clinical effects of the above target relations are unknown at this time.