Class Explorer · Anti-infectives
Penicillins
Beta-lactams binding penicillin-binding proteins: wall synthesis stops, bactericidal, time-dependent killing.
Members
AmoxicillinThe everyday aminopenicillin: reliable gram-positive and respiratory coverage, gentle on almost everyone.Piperacillin-tazobactamThe broad empiric workhorse, and a stewardship problem waiting to be de-escalated.
Also in this class: Penicillin V/G (streptococci) · Cloxacillin (anti-staphylococcal) · Piperacillin-tazobactam (broad + pseudomonal). Full pages arrive as the library grows.
Compare the members
Amoxicillin
- Spectrum note
- Strep, many respiratory organisms
- Distinguishing point
- Add clavulanate for beta-lactamase producers
Shared across the class
- Indications
- Respiratory, dental, skin, and streptococcal infections by agent
- Adverse effects
- GI upset · Rash · True IgE anaphylaxis (rare) · C. difficile
- Contraindications
- Severe documented penicillin hypersensitivity
- Monitoring
- Response at 48-72 h · Diarrhea · Allergy-history verification before the first dose
What makes each agent different
- The family ladders from narrow (penicillin) through aminopenicillins (amoxicillin) to beta-lactamase-protected and antipseudomonal members.
- Clavulanate adds beta-lactamase protection, and most of the diarrhea.
De-labelling false penicillin allergies unlocks the best-tolerated antibiotics we have.
Last reviewed 2026-08-15 · Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed.