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  • Penicillins are a structurally-related class of Beta-lactam Antibiotics. Various functional subclasses have been defined which highlight the subclasses's antibiotic spectrum and route of administration. Note, that the names of individual drugs are interlinks.
Natural Penicillins
  • Overview
    • Natural penicillins were historically the first beta-lactam class and can be naturally purified from mold. These drugs are highly sensitive to beta-lactamases and are effective against an increasingly small range of bacteria as resistance increases.
  • Member Drugs
    • Penicillin G: Can only be given by injection as it is acid-labile and so inactivated by stomach acid
    • Penicillin V: An acid-stable form of penicillin which can be given orally
Extended-spectrum Penicillins
  • Overview
    • Extended spectrum Penicillins have improved permeability through the outer membrane of gram negative bacteria. Consequently, the spectrum of these drugs extends beyond those of the natural penicillins, thus giving them their "Extended-spectrum" namesake. Because these drugs are frequently sensitive to beta-lactamase, a beta-lactamase inhibitor is sometimes co-administered to further extend their spectrum.
  • Member Drugs
    • Ampicillin
    • Amoxicillin
Anti-staphylococcal Penicillins
  • Overview
    • This subclass of drugs is highly effective against Staphylococcus aureus because of is member's resistance to secreted beta-lactamase. However, they cannot permeate the gram negative outer membrane and are thus only effective against gram positive bacteria.
  • Member Drugs
Anti-Pseudomonal Penicillins
  • Overview
    • These drugs are especially effective against Pseudomonas aeruginosa. These drugs are sensitive to beta-lactamase and thus their spectrum can be extended with co-administration of beta-lactamase inhibitors.
  • Member Drugs
    • Ticarcillin
    • Carbenicillin
    • Piperacillin