Cephalosporins

Cephalosporins are bacteriocidal, meaning they can be used in an immuno-compromised patient. Bacteriostatic cannot be used in an immuno compromised patient because all that would do is inhibit the growth of the bacteria but not kill it.  Bacteriocidal means it kills.

Cephalosporins have cross allergenicity with penicillins. There is a 10% chance that if a patient is allergic to penicillin, that they will be allergic to cephalosporins. If they have had a history of anaphylactic shock with penicillin, we won’t risk it. If it was just something like a rash, we could take the risk if it’s appropriate.

They all start with Cef- or Ceph- so they are easy to identify.  The cephalosporins are broken down into generations.  You need to know the differences between 1st, 2nd and 3rd generations.

1. The first generation doesn’t cross the BBB, so it’s ineffective against meningitis.
2. The second generation doesn’t cross the BBB, except for cefuroxime.
3. The third generation crosses the BBB.

Recap

• Bacteriocidal
• 10% cross allergenicity with penicillins
• First generation does not cross blood brain barrier (BBB)
• Only cefuroxime of second generation crosses BBB
• All 3rd generation cross BBB

First Generation Cephalosporins

Spectrum

• E. Coli
• Staph
• Hemophilus influenza
• Klebsiella (can cause respiratory infections)

Examples

• First Generation Oral
  • Cephalexin (Keflex)
• First Generation Injectable
  • Cephalothin (Keflin)
  • Cephapirin (Cefadyl)
  • Cefazolin (Kefzol, Ancef)

Second Generation Cephalosporins

Second generation has the same spectrum as the first generation but we are adding to it. In other words this spectrum is broader.

• May be effective in first generation resistance
• Spectrum
  • Bacteroides are anaerobes that live without oxygen. They can cause GI, respiratory, and skin infections.

Examples

• Second Generation Oral
  • Cefaclor (Ceclor)
  • Cefuroxime (Ceftin) (the only one here that crosses the BBB)
  • Cefadroxil (Duricef)
• Second Generation Injectable
  • Cefoxitin (Mefoxin)
  • Cefotetan (Cefotan)
  • Cefuroxime (Zinacef)

Third Generation Cephalosporins

Third generation has the same spectrum as first and second and we are adding to it. In this case we are getting even closer to a risk of a super-infection.

• May be effective against organisms resistant to 1st and 2nd generation
• Synergistic with aminoglycosides
• Spectrum
  • Similar to second generation
  • Pseudomonas

Examples

• Third Generation Oral
  • Cefdinir (Omnicef)
• Third Generation Injectable
  • Cefoperazone (Cefobid)
  • Cefotaxime (Claforan)
  • Ceftriaxone (Rocephin)
  • Ceftazimide (Fortaz, Tazicef, Tazimide)