Cephalosporins/Carbapenems/Monobactams

Question 1

Cephalosporins: characteristics

Answer 1

• classified based on generations: with each generation having more expanded gram neg spectrum
• mech of action is same as for pcbs

Question 2

1st Generation Cephalosporin =

Answer 2

• Cefazolin and Cephalexin
• Cover mostly Gram + cocci
• Used in surgical prophylaxis, MSSA, Strep Pyogens (pharyngitis and cellulitis)
• Few gram negs: E.coli, Klebsiella and proteus

Question 3

2nd Gen Cephalosporin =

Answer 3

• Cefoxitin and Cefaclor
• Less gram + coverage
• More active against Gram negs: H. flu, Enterobacter, Moraxella, Klebsiella, Neissaria, E.coli and Proteus
• also has increased anaerobic coverage
• Very good for Intra abdominal infxns or PID

Question 4

3rd Gen Cephalosporin =

Answer 4

Ceftriaxone and Cefotaxime

• Less gram + coverage: but ok for Strep
• Wider Gram neg spectrum and activity
• Good for Hospitalized Community Acquired Pneumonia
• Good for CSF penetration
• Preferred tx for Meningitis

Question 5

4th Gen Cephalosporin =

Answer 5

• Cefepime (Maxipeme)
• Useful for nosocomial infxns
• Good spectrum against gram neg organisms
• Still has Gram + coverage
  - -> Ideal for suppressed immune system
  
  • -> and for Empirical therapy

Question 6

Carbapenems =

Answer 6

Imipenem (primaxin) 
Meropenem (Merrem) 
Ertapenem (Invanz) 
-broadest spectrum of all the B lactams 
-Gram +/- aerobes and anaerobes
-penetrates tissues well 
-Resistant to B lactamase: emperic tx of mized aerobic and anaerobic infxns or nocosomial infxns

Question 7

Monobactams

Answer 7

Aztreonam 
-Only for Gram Neg infxns 
-will not work on anaerobes 
-Good empiric therapy when combines with abc that covers gram + 
Can be used in PCN allergic patients