Metronidazole and Tinidazole

ByBrian J. Werth, PharmD, University of Washington School of Pharmacy
Reviewed/Revised May 2024
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antibiotic. It enters bacterial cell walls and disrupts DNA and inhibits DNA synthesis in certain microorganisms.

Pharmacokinetics of Metronidazole and Tinidazole

Metronidazole is metabolized presumably in the liver and excreted mainly in urine, but elimination is not decreased in patients with renal insufficiency. However, because metronidazole metabolites may accumulate in patients with end-stage renal disease, these patients should be monitored for metronidazole-associated adverse effects such as central nervous system effects, including headaches, convulsions, and peripheral neuropathy (mainly numbness or paresthesias in an extremity).

metronidazole, allowing for less frequent dosing.

Indications for Metronidazole and Tinidazole

Metronidazole is used primarily for infections caused by obligate anaerobes, often with other antimicrobials. Metronidazole is the antibiotic of choice for bacterial vaginosis. It also has other clinical uses (see table ).

Table

Contraindications to Metronidazole and Tinidazole

Use of Metronidazole and Tinidazole During Pregnancy and Breastfeeding

metronidazole during pregnancy; however, in some studies, cleft lip (with or without cleft palate) was reported in neonates of women who took metronidazole during the first trimester. Some experts advise avoiding metronidazole during the first trimester, although the Centers for Disease Control and Prevention's (CDC) 2021 sexually transmitted infections treatment guidelines indicate that a single 2-g dose can be used at any stage of pregnancy to treat trichomoniasis.

tinidazole is avoided during pregnancy. Breastfeeding should be deferred for 72 hours after a single 2-g oral dose of tinidazole.

Adverse Effects of Metronidazole and Tinidazole

  • Gastrointestinal disturbances

  • Central nervous system effects and peripheral neuropathy

  • Disulfiram-like reaction

Metronidazole can cause a metallic taste and dark urine.

Dosing Considerations for Metronidazole and Tinidazole

Metronidazole doses are usually decreased 50% in patients with significant liver disease; tinidazole has not been studied in liver disease and should be used with caution if at all.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  1. Centers for Disease Control and Prevention (CDC): Sexually Transmitted Infections Treatment Guidelines (2021)

Drugs Mentioned In This Article
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