The curious characteristics of pyrazinamide: A review

Ying Zhang, D. Mitchison

Research output: Contribution to journalReview articlepeer-review

461 Scopus citations


Pyrazinamide (PZA) is an important sterilising tuberculosis drug that helps to shorten the duration of current chemotherapy regimens for tuberculosis. When first discovered, it had activity in murine tuberculosis but no apparent in vitro activity, and its subsequent use in treatment depended largely on classic experiments at Cornell University, which showed its requirement for an acid pH for activity and its sterilising activity in the mouse. Recent studies have shown that PZA enters Mycobacterium tuberculosis by passive diffusion, is converted to pyrazinoic acid (POA) by nicotinamidase/pyrazinamidase (PZase) and is then excreted by a weak efflux pump. Protonated POA (HPOA) is reabsorbed into the bacilli under acid conditions and accumulates because the efflux pump is inefficient, causing cellular damage. Unlike other antibacterials, PZA has no defined target of action. PZA is more active against old than against actively growing cultures, probably because the energy production and efflux pump would be slowed down by low bacterial metabolism. This review deals with the activity of PZA in vitro, in macrophages and in animal models. It describes the evidence from clinical trials that it is an effective sterilising drug that acts synergistically with rifampicin. The highly diverse mutations in the PZase gene (pncA) that lead to loss of PZase activity cause PZA resistance. Methods for susceptibility determination either as tests against PZA or nicotinamide in liquid and solid media, as tests for PZase activity or for mutations in pncA, are reviewed.

Original languageEnglish (US)
Pages (from-to)6-21
Number of pages16
JournalInternational Journal of Tuberculosis and Lung Disease
Issue number1
StatePublished - Jan 1 2003


  • Drug susceptibility testing
  • Mechanisms of action and resistance
  • Mycobacterium tuberculosis
  • Nicotinamidase and pyrazinamidase
  • Pyrazinamide

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Infectious Diseases


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