What is the treatment for dental infection using Metronidazole (antibiotic)?

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Last updated: May 23, 2025 • View editorial policy

From the Guidelines

Metronidazole is a recommended antibiotic for treating dental infections, particularly those caused by anaerobic bacteria, and should be prescribed at a dose of 250-500 mg three times daily, as indicated in the guidelines by the Infectious Diseases Society of America 1.

Key Considerations

  • Metronidazole has good activity against anaerobes, but no activity against aerobes, making it essential to combine it with another antibiotic like amoxicillin for broader coverage against the mixed bacterial flora present in dental infections.
  • The recommended dose of metronidazole is 250-500 mg three times daily, which can be adjusted based on the severity of the infection and the patient's response to treatment.
  • Patients should take the full course of antibiotics even if symptoms improve before completion, and metronidazole should be taken with food to minimize gastrointestinal side effects.
  • Alcohol must be strictly avoided during treatment and for 48 hours afterward to prevent a disulfiram-like reaction.

Important Details

  • Common side effects of metronidazole include metallic taste, nausea, and darkened urine.
  • Metronidazole is particularly effective against anaerobes because it creates toxic metabolites within these bacteria, damaging their DNA and causing cell death.
  • However, antibiotics alone are not sufficient treatment for dental infections - definitive treatment typically requires dental procedures such as drainage, root canal therapy, or tooth extraction to remove the source of infection.

Additional Recommendations

  • The guidelines also recommend considering the use of other antibiotics, such as amoxicillin-clavulanate, amplicillin-sulbactam, or moxifloxacin, depending on the severity of the infection and the patient's medical history 2.
  • It is essential to note that the bacteriology of dental infections can vary, and empirical therapy might miss pathogens, making it crucial to consider the use of broader empirical coverage for abscesses and more focused therapy for nonpurulent infected wounds 3.

From the FDA Drug Label

Anaerobic Bacterial Infections Metronidazole tablets are indicated in the treatment of serious infections caused by susceptible anaerobic bacteria INTRA‑ABDOMINAL INFECTIONS, including peritonitis, intra‑abdominal abscess, and liver abscess, caused by Bacteroides species including the B. fragilis group (B. fragilis, B. distasonis, B. ovatus, B. thetaiotaomicron, B vulgatus), Clostridium species, Eubacterium species, Peptococcusniger, and Peptostreptococcus species. SKIN AND SKIN STRUCTURE INFECTIONS caused by Bacteroides species including the B. fragilis group, Clostridium species, Peptococcus niger, Peptostreptococcus species, and Fusobacterium species

The treatment of dental infections with metronidazole is not explicitly mentioned in the provided drug label. However, metronidazole is indicated for the treatment of anaerobic bacterial infections, which may include some types of dental infections.

  • Key points:
    • Metronidazole is used to treat serious infections caused by susceptible anaerobic bacteria.
    • The label does not specifically mention dental infections as an indication for metronidazole use.
    • Metronidazole may be used to treat infections caused by Bacteroides species, Clostridium species, and other anaerobic bacteria, which can be involved in some dental infections. 4

From the Research

Dental Infection Treatment with Metronidazole

  • Metronidazole is effective against anaerobic gram-negative bacilli, but its use alone in treating acute odontogenic infections is not recommended due to its moderate effectiveness against facultative and anaerobic gram-positive cocci 5.
  • The combination of amoxicillin/clavulanate and metronidazole is a widely-accepted empirical regimen for infections of the odontogenic spaces, but metronidazole may not be necessary after drainage in healthy subjects 6.
  • Metronidazole is still the drug of choice for treating anaerobic infections, with low rates of resistance and good clinical results in treating infections caused by Bacteroides species, fusobacteria, and clostridia 7.
  • In periodontal diseases, metronidazole offers a high degree of efficacy and relatively few adverse side effects, making it a preferred drug against anaerobic infections 8.
  • Metronidazole has been shown to be as effective as parenteral penicillin in treating acute dental infections, with obligate anaerobes being the important pathogens in these infections 9.

Key Points

  • Metronidazole is effective against anaerobic bacteria, but its use should be considered in combination with other antibiotics for treating odontogenic infections 5, 6.
  • The decision to use metronidazole should be based on assessment of clinical and laboratory markers of infection 6.
  • Metronidazole is a cost-effective drug with minor adverse effects, making it a suitable option for treating anaerobic infections 7.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.