Dr. Bawoh. M

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Pharmacology of Cephalosporins: General Overview Bawoh. M PhD. [email protected]

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Page 1: Dr.  Bawoh.  M

Pharmacology of Cephalosporins:General Overview

Bawoh. M PhD.

[email protected]

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β- lactams: cell wall inhibitors

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β-lactam ring

•The β-lactam ring is a common structure for:•Penicillins•Cephalosporins•Monobactams•Carbapenems

• Bacteria will target this ring to gain resistance.

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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.

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Mechanism of action 1

•Some PBP have transpeptidase activity.• Transpeptidase activity is essential in cell wall synthesis.

•Beta-lactams bind PBP (Penicillin Binding Proteins).

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Mechanism of action 2

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Cephalosporins: characteristics

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Chemical structure of cephalosporins

• Derived from 7-aminocephalosporanic acid.

• They suffer the “attack” of bacteria at their beta-lactam ring.

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First gen. cephalosporins.:

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1st Generation cephalosporins: antibacterial coverage

Active mainly against Gram positive cocci. Less active against Gram negative.

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Clinical uses of first gen. cephalosporins

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2nd generation cephalosporins

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2nd generation cephalosporins. Antibiotic coverage

Increased coverage against Gram negatives, while keeping coverage against Gram +.

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3rd generation cephalosporins

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3rd generation cephalosporinsCoverage

Increased coverage against Gram negatives.Decreased coverage against Gram +

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3rd generation cephalosporinsClinical uses

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Ceftriaxone and meningitis

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4th generation cephalosporins

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4th generation cephalosporinsAntibacterial coverage

Coverage against Gram + and Gram -, good activity against β-lactamase producing bacteria.