Core pharmacology

Class Group

ANTIBIOTIC:
PENICILLIN

Legacy Cicm Level

Level 1

Introduction

Betalactam

Mechanism of action

Contains a beta lactam ring structure. Betalactam antibiotics inhibit the growth of sensitive bacteria by inactivating transpeptidase enzymes located in the bacterial cell membrane, inhibiting crosslinkage of peptidoglycans and thus impairing cell wall synthesis

Antimicrobial Spectrum

Moderate spectrum
Semisynthetic
Can penetrate some gram
negative outer membranes,
but susceptible to betalactamases. Often given with clauvanic acid
Targets
Strep, Listeria, Enterococcus, Haemophilus

Resistance Mechanism

Bacteria produce beta lactamases, which hydrolyse and inactivate the antibiotic

Resistance
MRSA
Many Staph
-Betalactamase prod

Absorption

BA 62%

Distribution

penetration into CSF occurs with inflamed meninges only

Protein binding

20% PB

Metabolism

Some Hepatic Metabolism

Excretion

Mostly unchanged in urine.
Rest is feces and bile