Tinidazole microbiology

Tinidazole

TINDAMAX® FDA Package Insert
Description
Clinical Pharmacology
Microbiology
Indications and Usage
Contraindications
Warnings and Precautions
Adverse Reactions
Drug Interactions
Overdosage
Dosage and Administration
Clinical Studies
How Supplied
Labels and Packages

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:  Ahmed Zaghw, M.D. [2]

## Microbiology

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### Mechanism of Action

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Tinidazole is an antiprotozoal, antibacterial agent. The nitro- group of tinidazole is reduced by cell extracts of Trichomonas. The free nitro- radical generated as a result of this reduction may be responsible for the antiprotozoal activity. Chemically reduced tinidazole was shown to release nitrites and cause damage to purified bacterial DNA in vitro. Additionally, the drug caused DNA base changes in bacterial cells and DNA strand breakage in mammalian cells. The mechanism by which tinidazole exhibits activity against Giardia and Entamoeba species is not known.

Antibacterial: Culture and sensitivity testing of bacteria are not routinely performed to establish the diagnosis of bacterial vaginosis. The standard methodology for the susceptibility testing of potential bacterial pathogens, Gardnerella vaginalis, Mobiluncus spp. or Mycoplasma hominis, has not been defined. The following in vitro data are available, but their clinical significance is unknown. Tinidazole is active in vitro against most strains of the following organisms that have been reported to be associated with bacterial vaginosis:

*     Bacteroides spp.

*     Gardnerella vaginalis

*     Prevotella spp.

Tinidazole does not appear to have activity against most strains of vaginal lactobacilli.

Antiprotozoal: Tinidazole demonstrates activity both in vitro and in clinical infections against the following protozoa:Trichomonas vaginalis; Giardia duodenalis (also termed G. lamblia); and Entamoeba histolytica.

For protozoal parasites, standardized susceptibility tests do not exist for use in clinical microbiology laboratories.

#### Drug Resistance

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The development of resistance to tinidazole by G. duodenalis, E. histolytica, or bacteria associated with bacterial vaginosis has not been examined.

#### Cross-resistance

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Approximately 38% of T. vaginalis isolates exhibiting reduced susceptibility to metronidazole also show reduced susceptibility to tinidazole in vitro. The clinical significance of such an effect is not known.[1]

## References

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1. ↑ "TINDAMAX (TINIDAZOLE) TABLET, FILM COATED [MISSION PHARMACAL COMPANY]".

Adapted from the FDA Package Insert.