Anti gram negative drugs
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Transcript of Anti gram negative drugs
*Anti gram negative drugs
Noreen Mohammed Naguib Mosaad
5212322G.11
Third Generation CephalosporinsExamples:Cefoperazone
The broadest spectrums of all cephalosporins
The lowest activities against G+ vebacteria
The highest resistance to β-lactamase
The best penetration into the CSF; almost no nephrotoxicity
Some of them are effective against pseudomonas and enteric bacilli
Fourth Generation Cephalosporins
•Examples : Cefepime
Similar to third generation
More resistant to hydrolysis by beta lactamase
It is cleared by the kidneys
It is useful in treatment of infections caused by enterobacter
AminoglycosidesMechanism of action:
•Aminoglycosides are irreversible inhibitors of bacterial protein synthesis.Antibacterial spectrum:
•All aminoglycosides are bactericidal. They are effective only against aerobic gram-negative organisms
They include:a)Streptomycin
b)Gentamicin
c)Neomycin
d)Tobramycin
Pharmacokinetic Properties•Aminoglycosides are poorly absorbed after
oraladministration, , because they are highly polar drugs. They must be given parenterally.
•Except Neomycinis neverused systemically
Concentrations in C.S.F are inadequate even when the meninges are inflammed.
•Aminoglycosides are cleared by the kidney
Adverse effects1-Ototoxicity
2-Nephrotoxicity.Binds tightly to renal tissue. Reduce dosage in patients with renal disease
3-Hypersensitivity
Contact dermatitis is a common reaction to topically applied neomycin.
Therapeutic usesUsed against gram-negative enteric bacteria
Used in combination with a beta-lactam antibiotic (e.g. penicillin) in order to extend coverage to include potential gram-positive pathogens.
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