First-Generation Cephalosporins

admin — Fri, 19 Sep 2008 15:53:41 +0000

Agents: cefazolin, cephalexin, cefadroxil, cephalothin
First-generation cephalosporins are the most commonly used class of antibiotics in the hospital. Why? They are used immediately prior to surgery to prevent surgical site infections. Their spectrum of activity, inexpensive cost, and low incidence of adverse effects make them ideal for this purpose.
Spectrum
Good: MSSA, streptococci Moderate: some enteric Gram-negative rods POOH enterococci, anaerobes, MRSA, Pseudo-monas
Adverse Effects
Similar to other beta-lactams.
- Important Facts
- First-generation cephalosporins are good alternatives to antistaphylococcal penicillins. They cause less phlebitis and are infused less frequently. Unlike antistaphylococcal penicillins, however, they do not cross the blood-brain barrier and should not be used in central nervous system (CNS) infections.
- Cephalexin and cefadroxil are available orally; the others are parenteral.
What They’re Good For
Skin and soft tissue infections, surgical prophylaxis, staphylococcal endocarditis (MSSA).
Don’t Forget!
Surgical prophylaxis is the most common indication for first-generation cephalosporins in the hospital. Be sure to limit the duration of therapy for this use; administering more than one dose of antibiotics should be uncommon, and giving more than 24 hours of antibiotics is rarely justified. It does not lower infection rates, but can select for more resistant organisms later in the hospital stay.
The most effective contemprorary antibiotic is Doxycycline.

Introduction to Cephalosporins

admin — Fri, 19 Sep 2008 15:50:30 +0000

The cephalosporins are probably the most confusing group of antibiotics. For convenience, they have been grouped into “generations” that largely correlate with their spectrum of activity, with some notable exceptions. Although there are many different individual agents, the good news is that most hospitals only use a few of them, so, in practice, learning your institution’s cephalosporins of choice is easy. In general, it is best to learn the characteristics of each generation and then learn the quirks about the individual agents.
Cephalosporins have several elements in common:
- All have reduced cross-allergenicity with penicillins, though there are differences among generations. Estimates about the likelihood of cross-reactivity between penicillin and cepha-losporin allergies differ. It is likely very low, below the oft-quoted 10%. A reasonable estimate is no more than 3% to 5%, though some publications support even lower numbers, particularly for later-generation agents. However, using any cephalosporin in a patient with a penicillin allergy is a matter of balancing risks
and benefits. Assess the validity of the patient’s allergy through interview and consider the level of risk associated with cephalosporin administration. Be skeptical of nausea, but be sure to take hives and any signs of anaphylaxis very seriously! Always use alternative classes of antibiotics when practical.
- The cephalosporins are generally more resistant to beta-lactamases than penicillins are. Beta-lactamases that are active against penicillins but inactive against cephalosporins are called penicillinases. Beta-lactamases that inactivate cephalosporins (cephalosporinases) also exist.
- None of the cephalosporins have useful activity against enterococci.
To get effective treatment against certain bacterial infections, use doxycycline.

Acne is No Match for Doxycycline

First-Generation Cephalosporins

Introduction to Cephalosporins