Cefonicid has an unesterified D-mandelic acid moiety at C-7 and a methylsulfothiotetrazole group at C-3.
The latter is related to the MTT moiety mentioned above under cefamandole nafate; however, the clotting
problems and Antabuse-like side effects associated with MTT have not been reported with cefonicid. The
extra acid group in the C-3 side chain leads to this molecule being sold as an injectable disodium salt. Pain
and discomfort at IM sites is experienced by some patients, as is a burning sensation and phlebitis.
Cefonicid has a longer half-life than the other members of its group but achieves this at the price of
somewhat lower potency against Gram-positive bacteria and aerobes. The drug is somewhat unstable, needs
to be protected from light and heat, and may yellow or darken. If modest, however, this does not necessarily
mean that the potency has decreased significantly, but overt precipitation does. Kirby-Bauer disk testing
may overestimate the sensitivity of β-lactamase–producing bacteria to this agent, so some extra caution in
interpretation of laboratory results is required.
A semi-synthetic cephalosporin antibiotic related to Cefamandole. Antibacterial
ChEBI: A cephalosporin bearing {[1-(sulfomethyl)-1H-tetrazol-5-yl]sulfanyl}methyl and (R)-2-hydroxy-2-phenylacetamido groups at positions 3 and 7, respectively, of the cephem skeleton.
Activity against Gram-positive and Gram-negative organisms
in vitro is depressed by the presence of 50% serum. It is highly
bound to plasma protein (98%) and has an extended plasma
half-life of 4.5–5 h. A 1 g intramuscular dose achieves a mean
peak plasma concentration of around 83 mg/L. Following a
1 g intravenous bolus dose, mean peak plasma concentrations
of 130–300 mg/L have been reported. In patients treated for
community-acquired pneumonia, concentrations of 2–4 mg/L
have been found in sputum.
It is predominantly excreted by renal secretion, 83–89%
being recovered unchanged in the urine over 24 h. Plasma
half-life is linearly related to creatinine clearance. As a
result of its high protein binding it is not removed by
hemodialysis.
It is generally well tolerated; pain on injection, rash and
positive Coombs’ test are reported in some patients. It has
been used to treat respiratory, soft tissue and urinary infections.
Available in Italy.
Cefonicid, 7-D-mandelamido-3-[[(1-sulfomethyl]-1H-tetrazol-5-yl]thio] methyl]-
8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid (32.1.2.26), is structurally similar
to cefamandole and differs in the presence of a sulfonic acid group in the methyl substituent
of the tetrazol ring. It is synthesized by a method analogous to that of the synthesis of
cefamandole.
