What are examples of systemic antibiotics?

Examples of Systemic Antibiotics

Systemic antibiotics include amoxicillin, amoxicillin-clavulanate, cephalosporins, macrolides, fluoroquinolones, and tetracyclines, which are administered orally or parenterally to treat various bacterial infections throughout the body. 1

Beta-lactam Antibiotics

• Aminopenicillins: Amoxicillin is a reference compound for respiratory infections, effective against Streptococcus pneumoniae and other common respiratory pathogens 1
• Beta-lactam/beta-lactamase inhibitor combinations: Amoxicillin-clavulanate (Augmentin) is recommended for respiratory infections with suspected beta-lactamase producing organisms like Haemophilus influenzae and Moraxella catarrhalis 1, 2
• Cephalosporins:
  • First generation: Alternative to amoxicillin for certain infections 1
  • Second generation: Cefuroxime-axetil for respiratory infections 1
  • Third generation: Cefpodoxime-proxetil, cefotiam-hexetil, and cefixime for specific indications 1

Macrolides and Related Antibiotics

• Macrolides: Used as alternatives in patients with beta-lactam allergies or for specific pathogens 1
• Pristinamycin: Alternative for patients with beta-lactam allergies 1
• Telithromycin: Used in specific respiratory infections when other options are not suitable 1

Tetracyclines

• Doxycycline: Alternative treatment for respiratory infections, particularly in patients with beta-lactam allergies 1

Fluoroquinolones

• Respiratory fluoroquinolones: Levofloxacin and moxifloxacin are active against pneumococci and recommended as second-line agents for respiratory infections 1
• Older fluoroquinolones: Ofloxacin and ciprofloxacin have limited activity against pneumococci and are not recommended for respiratory infections 1

Other Systemic Antibiotics

• Trimethoprim-sulfamethoxazole (Cotrimoxazole): Not recommended as first-line therapy for respiratory infections due to inconsistent activity against pneumococci and poor benefit/risk ratio 1

Clinical Considerations for Systemic Antibiotic Use

• Systemic antibiotics should be selected based on suspected pathogens, local resistance patterns, and patient factors 1
• Duration of therapy varies by indication: 5-10 days for most respiratory infections, 14 days for pneumonia 1, 3
• Therapeutic efficacy should be assessed within 48-72 hours of initiating treatment 1

Common Pitfalls in Systemic Antibiotic Selection

• Using broad-spectrum antibiotics when narrow-spectrum would suffice can promote antimicrobial resistance 4, 5
• Failure to consider local resistance patterns when selecting empiric therapy 2
• Inappropriate use of fluoroquinolones for conditions where other antibiotics would be more appropriate 1
• Not adjusting therapy based on culture results when available 1

Pediatric Considerations

• Dosing is weight-based and may differ from adult formulations 3, 6
• Amoxicillin-clavulanate dosing for children is typically 80-100 mg/kg/day of the amoxicillin component in divided doses 3
• Special formulations like Augmentin ES-600 are available for pediatric use in persistent or recurrent acute otitis media 2