Core pharmacology

Class Group

ANTIBIOTIC:
CEPHALOSPORIN

Legacy Cicm Level

Level 1

Introduction

3rd Generation Cephalosporin

Presentation

Powder for IV injection.
Does NOT precipitate in
calcium containing solutions

Mechanism of action

Beta lactam ring binds to multiple penicillin binding proteins (carboxy/endo/ transpeptidase) and
prevents crosslinking of bacterial peptidoglycan
inhibits cell wall synthesis
BROADER SPECTRUM

Bacteria eventually lyse due to ongoing activity of cell wall autolytic enzymes (autolysins and murein hydrolases) while cell wall assembly is arrested

Configuration: Stability against Betalactamases

Onset Peak Duration

1-2g q8hr

Antimicrobial Spectrum

Bacteriocidal

Active against: same as ceftriaxone

Not Active against: same as ceftriaxone

Adverse Effects Toxicity

Generally well tolerated
Hypersensitivity reactions (10% cross reactivity with penicillin allergies), thrombophlebitis, interstitial nephritis, low prothrombin, flushing and headaches with EtOH.

Third generation cephalosporins are particularly associated with antibiotic associated colitis.

Absorption

Poor oral absorb – given IV or IM only.

Distribution

Widely distributed and crosses the BB in meningitis. Good tissue penetration

Protein binding

35-50% PB

Metabolism

Active metabolite desacetyl-cefotaxime in the liver

Excretion

Mainly renal clearance

Half-life

Plasma T1/2 = 1-1.5 hrs