History

• Penicillins were originally isolated from Penicillium mold

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Pharmacology

Mechanism of Action

• β-Lactam Antibiotic (see β-Lactam Antibiotics, [[β-Lactam Antibiotics]]): inhibit the formation of peptidoglycan cross-links in the bacterial cell wall
  • Four-membered β-lactam ring of penicillin binds to the DD-transpeptidase enzyme

Classes of Penicillins

Natural Penicillins

• Benzathine Penicillin
• Penicillin G (Benzylpenicillin) (see Penicillin G, [[Penicillin G]])
• Penicillin V (Veetids) (see Penicillin V, [[Penicillin V]])
• Procaine Penicillin

Penicillinase-Resistant Penicillins

• Cloxacillin
• Dicloxacillin (see Dicloxacillin, [[Dicloxacillin]])
• Flucloxacillin (Floxapen, Staphylex, Softapen, Flubex, Flupen)
• Methicillin (see Methicillin, [[Methicillin]])
• Nafcillin (see Nafcillin, [[Nafcillin]])
• Oxacillin (see Oxacillin, [[Oxacillin]])

Aminopenicillins

• General Comments
  • Vulnerable to inactivation by β-lactamases
• Amoxacillin (see Amoxacillin, [[Amoxacillin]]): due to potential inactivation by β-lactamases, usually used in a formulation with a β-lactamase inhibitor (like clavulanic acid)
  • Amoxicillin/Amoxacillin-Clavulanic Acid (Augmentin) (see Amoxacillin-Clavulanic Acid, [[Amoxacillin-Clavulanic Acid]])
• Ampicillin (see Ampicillin, [[Ampicillin]]): due to potential inactivation by β-lactamases, usually used in a formulation with a β-lactamase inhibitor (like sulbactam)
  • Ampicillin/Ampicillin-Sulbactam (Unasyn) (see Ampicillin-Sulbactam, [[Ampicillin-Sulbactam]])
• Bacampicillin

Extended-Spectrum/Anti-Pseudomonal Penicillins

• General Comments
  • Have activity against many gram-negative organisms of the Enterobacteriaceae family (including Pseudomonas aeruginosa)
  • Vulnerable to inactivation by β-lactamases
• Acylaminopenicillins
  • Azlocillin
  • Mezlocillin
  • Piperacillin: due to potential inactivation by β-lactamases, usually used in a formulation with a β-lactamase inhibitor (like tazobactam)
    • Piperacillin/Piperacillin-Tazobactam (Zosyn) (see Piperacillin-Tazobactam, [[Piperacillin-Tazobactam]])
• Alpha-Carboxypenicillins
  • Carbenicillin
  • Ticarcillin: due to potential inactivation by β-lactamases, usually used in a formulation with a β-lactamase inhibitor (like clavulanic acid)
    • Ticarcillin/Ticarcillin-Clavulanic Acid (Timentin) (see Ticarcillin-Clavulanic Acid, [[Ticarcillin-Clavulanic Acid]])

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Adverse Effects

Pulmonary Adverse Effects

• Drug-Induced Pulmonary Eosinophilia (see Drug-Induced Pulmonary Eosinophilia, [[Drug-Induced Pulmonary Eosinophilia]])
  • Epidemiology: has been reported with Ampicillin

Dermatologic Adverse Effects

• Morbilliform Rash (see Exanthems, [[Exanthems]])
• Stevens-Johnson Syndrome and Toxic Epidmermal Necrolysis (see Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis, [[Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis]])

Other Adverse Effects

• Anaphylaxis (see Anaphylaxis, [[Anaphylaxis]])

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References

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