Penicillins were originally isolated from Penicillium mold
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]])
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]])