Antibiotic Treatments

 1. Use of Penicillin
  Penicillin V potassium is the preferred antibiotic for the treatment of odontogenic infections due to its narrow activity spectrum targeting a majority of gram-positive cocci and other anaerobic bacteria that frequently cause these infections (Drawz & Bonomo, 2010).
      
Mode of Administering
    Prescription Guides
    Penicillin works well when taken orally and is stable within the acidic environment of the stomach, although it should be taken prior to eating, as food reduces the rate of absorption of the drug. Penicillin is the oldest commercially produced and prescribed antibiotic and because of this many bacterial species have developed resistance to penicillin.

Resistant bacteria express an enzyme called beta-lactamase that breaks down the beta-lactam ring in the penicillin molecule. Follow-up treatment with other specific antibiotics to target resistant bacteria is advised if an odontogenic infection does not resolve following penicillin treatment.
When prescribing penicillin, it is important to note that up to 7% of the population has penicillin allergies that will require the use of an alternative antibiotic for primary treatment (Laskin, 2010). Penicillin can also interact with other commonly prescribed drugs.

The anticoagulant warfarin is enhanced in the presence of penicillin. Many oral contraceptives are inhibited by penicillin, so a patient should be advised to use additional forms of birth control during penicillin treatment (Association, 2009).

Penicillin is primarily eliminated from the body through secretion in the renal tubules. Therefore, renal impairment is a contraindication for prescribing penicillin (Wynn, 2016).
  2. Use of Amoxicillin
  Amoxicillin is a broad-spectrum antibiotic that has been prescribed with growing frequency to treat oral infections that are resistant to penicillin.
      Amoxicillin can be taken orally and is easily absorbed throughout the gastrointestinal tract. It is able to treat approximately 90% of gram-positive and 80% of gram-negative bacteria (Chunduri et al., 2012).
    Amoxicillin is structurally similar to penicillin, in that it also contains a beta-lactam ring although it is not as easily degraded by bacterial beta-lactamase.
    However, people with allergic reactions to penicillin may also exhibit allergic reactions to amoxicillin, and the previously described interactions of penicillin with other drugs also apply to amoxicillin.
    Gout treatment drugs including probenecid and allopurinol have been shown to elevate the levels of circulating amoxicillin when prescribed together.
    Amoxicillin decreases the renal clearance of methotrexate, causing toxicity that can lead to kidney failure, mucositis, nausea, and vomiting (Wynn, 2016).
  3. Use of Clindamycin
  Clindamycin is a macrolide antibiotic that works by inhibiting protein synthesis within bacteria by binding to the 50S ribosomal subunit, interfering with mRNA translation.
      Recommended Dosage
Clindamycin must be administered at high doses to kill bacteria, whereas lower doses only inhibit bacterial growth and proliferation. Both gram-negative and gram-positive anaerobic bacteria are suitable targets for clindamycin; however, it is not effective for treating most aerobic bacterial infections.

The primary application of clindamycin in treating oral infections is for use in patients with odontogenic infections who have allergies to amoxicillin or penicillin. Clindamycin can also be used as a second-round antibiotic for infections that were not completely resolved by beta-lactam antibiotics (Wynn, 2016).
Mode of Administering Clindamycin
Clindamycin is administered orally and is easily absorbed through the digestive tract. Macrophages and leukocytes within oral abscesses actively take up the molecule, improving its access to infections within the abscess. Clindamycin is primarily metabolized in the liver, which requires dosing considerations in patients with hepatic dysfunction.

Patients undergoing anesthesia that requires neuromuscular inhibitors should not be given clindamycin as the antibiotic has been shown to prolong the effect of these muscle relaxers. Clindamycin treatment can promote the overgrowth of Clostridium difficile in the intestines and cause pseudomembranous colitis, and therefore should not be used to treat patients with a history of colitis.
  4. Use of Erythromycin and Azithromycin
  Erythromycin and azithromycin are both macrolide antibiotics that can be used to treat odontogenic bacterial infections.
      Use of Erythromycin
Erythromycin can be used systemically and was commonly used to treat endocarditis following oral surgery, but it frequently causes side effects in the gastrointestinal tract. Additionally, bacteria have become increasingly resistant to erythromycin (Segura-Egea et al., 2017).
Use of Azithromycin
Azithromycin is an erythromycin derivative that is a broad-spectrum antibiotic and is effective against gram-positive and gram-negative bacterial species. Azithromycin has improved tissue absorption and persists within tissues for a longer duration than erythromycin.

Azithromycin can be used as either a second-line antibiotic or as a prophylactic treatment to prevent bacterial endocarditis resulting from invasive dental procedures.

Metabolism of Azithromycin
Azithromycin is primarily metabolized in the liver and therefore the dose should be carefully titrated in individuals with liver disease.

Azithromycin also increases the anticoagulant activity of warfarin and can interfere with drugs that prolong the QT interval to treat cardiac arrhythmias (Wynn, 2016).

  5. Metronidazole
  Metronidazole is a nitroimidazole class of antibiotics that functions by directly binding to bacterial DNA to cause cell death.

Due to this route of action, metronidazole can be used in combination with other classes of antibiotics if other first-line antibiotic treatments have failed to resolve the infection. While metronidazole is effective at killing gram-positive and gram-negative bacteria, it is not:
      Effective in treating aerobic bacteria (Wynn, 2016).
    In addition to also enhancing the effects of warfarin, metronidazole can cross into the placental and fetal circulation and is therefore contraindicated by pregnancy.