Metronidazole, its bioactive metabolites and acne.

Metronidazole's activity has been established in both acneiform rosacea and acne vulgaris. Recent research indicating that the breakdown products of several antibiotics, including metronidazole, may have considerably greater activity than the parent compound, prompted a re-examination of the susceptibility of Propionibacterium acnes, the organism involved in the fundamental pathogenesis of acne vulgaris. Although the organism was marginally more sensitive to the hydroxy derivative, MIC levels were still outside the readily attainable therapeutic range. The beneficial effects of metronidazole in acne vulgaris are attributable to its anti-inflammatory activities rather than its antibacterial ones.