Aminopenicillins
Aminopenicillins are amoxicillin and ampicillin, which are broad-spectrum penicillin antibiotics with enhanced gram-negative activity compared to natural penicillins. 1, 2, 3
Core Aminopenicillin Antibiotics
The two primary aminopenicillins used in clinical practice are:
- Amoxicillin - A semisynthetic penicillin analog of ampicillin with broad-spectrum bactericidal activity against many gram-positive and gram-negative microorganisms 1
- Ampicillin - A semisynthetic penicillin derived from 6-aminopenicillanic acid, the basic penicillin nucleus 2, 3
Prodrug Formulations
Several prodrug formulations exist that are converted to ampicillin after absorption:
- Bacampicillin - A prodrug that is rapidly split upon gastrointestinal absorption to yield circulating ampicillin 4, 5
- Pivampicillin - Another prodrug formulation that converts to ampicillin after absorption 6, 4
- Talampicillin - A prodrug that similarly yields ampicillin after gastrointestinal absorption 4, 5
Combination Products with Beta-Lactamase Inhibitors
Aminopenicillins are frequently combined with beta-lactamase inhibitors to extend their spectrum:
- Amoxicillin-clavulanate (amoxicillin-clavulanic acid) - Combines amoxicillin with the beta-lactamase inhibitor clavulanic acid 6, 7
- Amoxicillin-sulbactam - Combines amoxicillin with sulbactam, another beta-lactamase inhibitor 8
- Ampicillin-sulbactam - Combines ampicillin with sulbactam 3
Clinical Spectrum and Applications
Aminopenicillins provide coverage against:
- Gram-positive organisms: Streptococcus pneumoniae, Streptococcus pyogenes, non-penicillinase-producing Staphylococcus aureus 6, 8
- Gram-negative organisms: Escherichia coli, Proteus mirabilis, Haemophilus influenzae, Moraxella catarrhalis, Shigella, Salmonella 2, 3, 8
- Enterococci: Ampicillin remains the preferred anti-enterococcal antibiotic in penicillin-tolerant patients 7, 9
Preferred Formulations for Clinical Use
For oral therapy, amoxicillin and bacampicillin are the most suitable aminopenicillins due to superior pharmacokinetics and reduced side effects compared to ampicillin. 4, 5
- Amoxicillin causes less diarrhea than ampicillin when given orally 5
- For parenteral administration, both ampicillin and amoxicillin are appropriate primary choices 4
Common Clinical Applications in Guidelines
Aminopenicillins are recommended as first-line therapy for:
- COPD exacerbations: Aminopenicillin with or without macrolide 6
- Community-acquired pneumonia: Aminopenicillin or aminopenicillin/beta-lactamase inhibitor with or without macrolide 6
- Acute bacterial rhinosinusitis: High-dose amoxicillin or amoxicillin-clavulanate 6
- Pleural infections: Amoxicillin with clavulanic acid or metronidazole for community-acquired cases 6