Is ampicillin indicated in the treatment of oral infections?

From the Guidelines

Ampicillin is not the preferred treatment for oral infections due to its limited spectrum of activity and susceptibility to beta-lactamase degradation. The treatment of oral infections typically involves the use of antibiotics with a broader spectrum of activity, such as amoxicillin, amoxicillin-clavulanate, clindamycin, or metronidazole, depending on the specific infection and severity 1.

Key Considerations

• The oral cavity contains a complex microbiome with many potential pathogens, including anaerobes that may not be adequately covered by ampicillin alone 1.
• Ampicillin has lower oral bioavailability compared to amoxicillin and is more susceptible to degradation by beta-lactamase enzymes produced by many oral bacteria 1.
• The Infectious Diseases Society of America recommends the use of amoxicillin-clavulanate, ampicillin-sulbactam, or ertapenem for the treatment of infections following animal or human bites, but ampicillin is not the first-line treatment for most oral infections 1.

Treatment Options

• Amoxicillin (500 mg three times daily for 5-7 days) is a common first-line treatment for oral infections 1.
• Amoxicillin-clavulanate, clindamycin (300 mg four times daily for 5-7 days), or metronidazole may also be used, depending on the specific infection and severity 1.
• Consultation with a dentist or physician is recommended to determine the most appropriate antibiotic based on the specific infection, severity, and patient factors such as allergies and medical history 1.

From the FDA Drug Label

Ampicillin capsules and Ampicillin for oral suspension are indicated in the treatment of infections caused by susceptible strains of the designated organisms listed below: Infections of the genitourinary tract including gonorrhea - E. coli, P. mirabilis, enterococci, Shigella, S. typhosa and other Salmonella and nonpenicillinase-producing N. gonorrhoeae Infections of the respiratory tract - Nonpenicillinase-producing H. influenzae and staphylococci, and streptococci including Streptococcus pneumoniae. Infections of the gastrointestinal tract -Shigella, S. typhosa and other Salmonella, E. coli, P. mirabilis, and enterococci.

The FDA drug label does not explicitly mention oral infections as an indication for ampicillin. However, it does mention infections of the respiratory tract, which may include some oral infections.

• The label lists specific types of infections and organisms that ampicillin is indicated for, but oral infections are not explicitly mentioned.
• Ampicillin may be used to treat some types of oral infections, but only if they are caused by susceptible strains of the designated organisms listed in the label 2. However, without explicit information, no conclusion can be drawn.

From the Research

Antibiotic Treatment for Oral Infections

• Ampicillin has been used to treat various infections, including oral infections of the upper airways such as otitis media, bronchitis, and pneumonia, with high success rates 3.
• However, the use of ampicillin in dental practice is not typically recommended as the first line of treatment, with penicillin G or penicillin V being preferred for dental infections of usual etiology 4.
• In the treatment of odontogenic infections, clindamycin has been shown to be a safe and effective alternative to ampicillin, with no isolates resistant to clindamycin found in one study 5.
• A 10-year retrospective study on orofacial infections found that the most frequent aetiology was odontogenic, and that causal bacteria showed a high antibiotic resistance rate, especially to Clindamycin and Metronidazole 6.
• Ampicillin-sulbactam, a combination of ampicillin and a beta-lactamase inhibitor, has been used to treat a range of bacterial infections, including those of the respiratory tract, urinary tract, and skin and soft tissue, and is available in both parenteral and oral forms 7.

Resistance and Efficacy

• The efficacy of ampicillin in treating oral infections may be limited by the development of resistant strains, such as those found in shigellosis 3.
• Clindamycin has been shown to be effective against a range of bacteria, including those causing odontogenic infections, with no resistance found in one study 5.
• However, a 10-year retrospective study found that Clindamycin resistance was highest among the antibiotics tested, with 25.8% of bacteria showing resistance 6.
• Ampicillin-sulbactam has been shown to be effective against a range of bacteria, but is not active against Pseudomonas aeruginosa and pathogens producing extended-spectrum beta-lactamases 7.