The nitroimidazooxazines (PA-824 and analogs): structure-activity relationship and mechanistic studies

Future Med Chem. 2010 Aug;2(8):1295-304. doi: 10.4155/fmc.10.207.


PA-824 is an experimental anti-tubercular agent that has a novel mechanism of action. It is effective against both active and persistent forms of the disease and has recently shown early bactericidal activity in a Phase II clinical trial. This review summarizes recent studies on the mode of action of PA-824 and outlines successful efforts to prepare more effective second-generation analogs. PA-824 displays unusual chemistry following both enzymatic and radiolytic reduction, which is clearly related to its activity as an anti-tubercular agent. The nitroreductase enzyme deazaflavin-dependent nitroreductase, reduces PA-824 with loss of the nitro group, generating reactive nitrogen species such as nitric oxide, which appear important in mediating the activity of the drug. Bioreductive drugs such as PA-824 hold the promise of shorter treatment regimens.

Publication types

  • Review

MeSH terms

  • Animals
  • Antitubercular Agents / chemistry*
  • Antitubercular Agents / pharmacology*
  • Humans
  • Mycobacterium tuberculosis / drug effects*
  • Nitroimidazoles / chemistry*
  • Nitroimidazoles / pharmacology*
  • Structure-Activity Relationship
  • Tuberculosis / drug therapy*


  • Antitubercular Agents
  • Nitroimidazoles
  • pretomanid