antibioticsbooks

74 PART 2 Antibacterial Drugs
Adverse Effects
Similar to those of other beta-lactams. Cephalosporins
with the N-methylthiotetrazole (MTT) side
chain—cefamandole, cefmetazole, and cefotetan—
can inhibit vitamin K production and prolong
bleeding. These MTT cephalosporins can also cause
a disulfiram-like reaction when co-administered
with ethanol. While most people in the hospital do
not have access to alcoholic beverages while being
treated for infections, outpatients need to be counseled
on this interaction. The interaction is a common
question on board exams.
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Important Facts
• Cefoxitin, cefotetan, and cefmetazole are
cephamycins. They are grouped with the
second-generation cephalosporins because
they have similar activity, with one important
exception: anaerobes. Cephamycins have activity
against many anaerobes in the GI tract, and
cefoxitin and cefotetan are often used for surgical
prophylaxis in abdominal surgery.
• Loracarbef is technically a carbacephem. You
should immediately forget this to allow room
for more important facts.
• Cefaclor, cefprozil, and loracarbef are available
only orally. Cefuroxime is available in both IV
and oral formulations, and the others are
IV only.
• Like first-generation cephalosporins, secondgeneration
agents do not cross the blood–brain
barrier well enough to be useful to treat CNS
infections.