antibioticsbooks

Cephalosporins
■■
Introduction to Cephalosporins
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 use only a few of them, so, in practice,
learning your institution’s cephalosporin 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. Figure 6–2
shows the general types of antimicrobial activity of
the cephalosporin generations.
Cephalosporins have several elements in
common:
• All are believed to have some cross-allergenicity
with penicillins, though there are differences
among generations. Estimates about the likelihood
of cross-reactivity between penicillin
and cephalosporin 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
69