Dr. Bawoh. M
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Pharmacology of Cephalosporins:General Overview
Bawoh. M PhD.
β- lactams: cell wall inhibitors
•The β-lactam ring is a common structure for:•Penicillins•Cephalosporins•Monobactams•Carbapenems
• Bacteria will target this ring to gain resistance.
Cell wall inhibitors: important features
• Cell wall inhibitors have bacericidal effect.
• They act sinergistically with amynoglycosides
• Time-dependent kinetics: the more time the drug binds the bacteria, the more effective it is.
Mechanism of action 1
•Some PBP have transpeptidase activity.• Transpeptidase activity is essential in cell wall synthesis.
•Beta-lactams bind PBP (Penicillin Binding Proteins).
Mechanism of action 2
Chemical structure of cephalosporins
• Derived from 7-aminocephalosporanic acid.
• They suffer the “attack” of bacteria at their beta-lactam ring.
First gen. cephalosporins.:
1st Generation cephalosporins: antibacterial coverage
Active mainly against Gram positive cocci. Less active against Gram negative.
Clinical uses of first gen. cephalosporins
2nd generation cephalosporins
2nd generation cephalosporins. Antibiotic coverage
Increased coverage against Gram negatives, while keeping coverage against Gram +.
3rd generation cephalosporins
3rd generation cephalosporinsCoverage
Increased coverage against Gram negatives.Decreased coverage against Gram +
3rd generation cephalosporinsClinical uses
Ceftriaxone and meningitis
4th generation cephalosporins
4th generation cephalosporinsAntibacterial coverage
Coverage against Gram + and Gram -, good activity against β-lactamase producing bacteria.