Cephalosporins
Upcoming SlideShare
Loading in...5
×
 

Cephalosporins

on

  • 2,697 views

 

Statistics

Views

Total Views
2,697
Views on SlideShare
2,697
Embed Views
0

Actions

Likes
2
Downloads
186
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Cephalosporins Cephalosporins Presentation Transcript

  • CEPHALOSPORINS
    • Semisynthetic antibiotics
    • Derived from cephalosporin-C obtained from a fungus
    • Cephalosporium
    • Chemically related to penicillins
    • Nucleus consists of a β -lactum ring fused to
    • dihydrothiazine ring (7-aminocephalosporanic acid)
    • - Bactericidal
  • CH CH 2 CH S NH C C N O R 1 1 2 Cephalosporin Amide linkage COOH C C R 2
  • CLASSIFICATION First generation Parenteral oral Cephalothin cefazolin Cephalexin Cephradine Cefadroxil Second generation Parenteral oral Cefuroxime Cefoxitin Cefaclor Cefuroxime axetil
  • Third generation Parenteral oral Fourth generation Parenteral Cefotaxime Ceftizoxime Ceftriaxone Ceftazidime Cefoperazone Cefixime Cefpodoxime proxitil Cefdinir Ceftibutin Cefepime Cefpirome
  • Individual cephalosporins differ in their: a) Antibacterial spectrum and relative potency against specific organism b) Susceptibility to β -lactamases from different organisms c) Pharmacokinetic properties d) Local irritancy on i.m. injection MOA Inhibition of cell wall synthesis
    • RESISTANCE
    • Alteration in target proteins (PBPs) reducing affinity for
    • the antibiotics
    • Impermeability to the antibiotic so that iy does not
    • reach its site of action
    • Elaboration of β -lactamases which destroy specific
    • cephalosporins
  • FIRST GENERATION Developed in 1960s Have high activity against Gram +ve but weaker against Gram –ve bacteria Cephalothin -1 st cephalosporin used clinically Active against- streptococci, staphylococci, gonococci meningococci etc.
  • SECOND GENERATION More active against Gram –ve organisms Some members active against anaerobes Cafoxitin - highly resistant to β -lactamases produced by gram –ve bacteria. Used in- surgical infections lung abscess
  • THIRD GENERATION Introduced in 1980s Highly active against gram-ve bacteria All are highly resistant to β -lactamases from gram –ve bacteria Cefotaxime Potent action on aerobic gram-ve as well as gram+ve bacteria Not so active on anaerobes
  • USE Hospital acquired infections Septicaemias Infections in immunocompromised patients FOURTH GENERATION CEPHALOSPORINS Developed in 1990s Highly resistant to β -lactamases Active - P.Aeruginosa and S.aureus
    • ADVERSE EFFECTS
    • Pain
    • Diarrhoea
    • Hypersensitivity reactions
    • Nephrotoxicity
    • Bleeding –hypoprothrombinemia
    • USES
    • As alternative to PnG in patients developing rashes
    • Respiratory,urinary & soft tissue infections-gram-ve
    • bacteria
    • Septicaemias caused by gram-ve organisms
    • Surgical prophylaxis
    • Meningitis caused by H.influenzae
    • Gonorrhoea
    • Thyphoid
    • Mixed aerobic-anaerobic infections seen in cancer patients
    • MONOBACTAMS
    • Aztreonam
    • Novel β -lactam antibiotic
    • Inhibit gram-ve enteric bacilli , H.influnzae &
    • pseudomonas
    • Do not inhibit gram+ve cocci
    • Dose 0.5-2g i.m or i.v. 6-12 hourly
    • Uses
    • Hospital acquired infections
    • In patients allergic to penicillins or cephalosporins
  • CARBAPENEMS Imipenem Extremely potent & very broad spectrum β -lactam antibiotic Effective against- gram+ve cocci P.aeruginosa anaerobes like- B.fragilis C.difficile Disadvantage - rapid hydrolysis by enzyme dehydropeptidase I Overcome by- giving in combination with cilastatin
  • Dose- imipenem-cilastatin 0.5g i.v. 6 hourly USES: Hospital acquired infections including cancer & AIDS patients