Cephalosporins, Carbapenems and Monobactams

• What is the chemical structure of cephalosporins composed of?

  Dihydrothiazine, beta-lactam ring, and acyl side chain
• How are cephalosporins resistant to penicillinase?

  They are partially resistant to penicillinase, a variant of beta-lactamase
• What happens to cephalosporins when exposed to bacterial cephalosporinase?

  They are easily destroyed by bacterial cephalosporinase, a variant of beta-lactamase
• What are the classifications of cephalosporins based on generation?

  • 1st Generation
  • 2nd Generation
  • 3rd Generation
  • 4th Generation
  • 5th Generation
• What is the primary activity of 1st generation cephalosporins?

  They have anti-staphylococcal activity
• How does the activity of 2nd generation cephalosporins compare to 1st generation?

  2nd generation has increased activity against G-ve bacteria compared to 1st generation
• Give an example of a 1st generation cephalosporin.

  Cefazolin
• What is an example of a 2nd generation cephalosporin?

  Cefaclor
• What is the spectrum of activity for 3rd generation cephalosporins?

  They have decreased activity against G+ve bacteria but increased activity against G-ve bacteria
• Name a 3rd generation cephalosporin.

  Cefotaxime
• What is a notable feature of 4th generation cephalosporins?

  They are extremely resistant to beta-lactamase
• Provide an example of a 4th generation cephalosporin.

  Cefepime
• What is the spectrum of activity for 5th generation cephalosporins?

  They have broad-spectrum activity, including against resistant strains
• Name an example of a 5th generation cephalosporin.

  Ceftaroline
• What are the pharmacokinetics of cephalosporins?

  • Similar to penicillins
  • 1st Gen: Unpredictable CSF penetration, not for meningitis
  • 2nd-4th Gens: Suitable for treating meningitis
  • Probenecid increases plasma levels and delays removal from CSF
• What are some therapeutic uses of cephalosporins?

  Prophylaxis against post-surgical infections, respiratory infections, UTIs, PID, nosocomial infections, and skin infections
• What is a common adverse reaction associated with cephalosporins?

  Allergy, which can cross-react with penicillins
• What is a notable toxicity associated with cephalosporins?

  Thrombophlebitis with IV and IM administration
• What is the mechanism of action for carbapenems?

  They are resistant to beta-lactamases and cephalosporinase
• What is the combination of imipenem and cilastatin used for?

  To denature RT-dipeptidase and enhance the effectiveness of imipenem
• What is the therapeutic use of carbapenems?

  They provide excellent broad-spectrum coverage for many infections, especially UTIs
• What is the antimicrobial activity of aztreonam?

  It has good anti G-ve activity but no activity against G+ve bacteria
• How does the antimicrobial activity of aztreonam compare to aminoglycosides?

  It has antimicrobial activity very close to aminoglycosides