antibioticsbooks

Beta-Lactams
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Introduction to Beta-Lactams
Beta-lactams include a wide variety of antibiotics
that seem to exist only to confuse students
and clinicians. Penicillins, cephalosporins, and
carbapenems are all beta-lactams. Monobactams
(aztreonam) are structurally similar, but they lack
one of the two rings that other beta-lactams have
and have little to no cross-allergenicity with other
beta-lactams. To make matters more confusing,
not all beta-lactams end in -cillin or -penem or start
with ceph-.
We believe the best approach to keeping betalactams
straight is to group them into classes and
learn the characteristics of each class. If you work
in a hospital, you will likely have only one or two
drugs of each class to worry about. Fortunately, all
beta-lactams have a few things in common.
• All beta-lactams can cause hypersensitivity
reactions, ranging from mild rashes to drug
fever to acute interstitial nephritis (AIN) to
anaphylaxis. There is some cross-sensitivity
among classes, but there is no way to predict
exactly how often that will occur. Studies on
the matter differ greatly in their conclusions,
though on the whole cross-sensitivity seems