This is a list of common β-lactam antibiotics—both administered drugs and those not in clinical use—organized by structural class. Antibiotics are listed alphabetically within their class or subclass by their nonproprietary name. If an antibiotic is a combination drug, both ingredients will be listed.
Penams
Narrow-spectrum
β-lactamase-sensitive
β-lactamase-resistant
Broad spectrum
Extended spectrum (Antipseudomonal)
Carboxypenicillins
Ureidopenicillins
Cephems
First generation (moderate spectrum)
Second generation (moderate spectrum) cefuroxime, cefaclor, cefprozil
With anti-Haemophilus activity
With anti-anaerobic activity
Third generation (broad spectrum)
Fourth generation (broad spectrum) (With β-lactamase stability and enhanced activity against Gram-positive bacteria and Pseudomonas aeruginosa)
Fifth generation* (broad spectrum) (activity against MRSA and variably VRE. *Not universally accepted nomenclature. NO Antipseudomonal activity, mostly ceftriaxone coverage with additional MRSA and some VRE)
Carbapenems and penems (Broadest spectrum of β-lactam antibiotics)
Monobactams
β-lactamase inhibitors