Pharmacotherapeutic group: Antibacterials for intramammary use, first-generation cephalosporins.
ATCvet code: QJ51DB90.
Pharmacodynamic properties
Cefalonium is an antibacterial drug of the first generation cephalosporin group which acts by inhibition of cell wall synthesis (bactericidal mode of action). The antibacterial activity is not impaired in the presence of milk.
Three mechanisms of resistance to cephalosporin are known: reduced permeability of the cell wall, enzymatic inactivation and absence of specific penicillin binding sites. In Gram-positive bacteria and particularly staphylococci, the main cephalosporin resistance mechanism is through alteration of penicillin binding proteins. In Gram-negative bacteria resistance may consist in the production of β-lactamases, especially extended-spectrum β-lactamases.
Cefalonium is active against: Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Trueperella pyogenes, Escherichia coli and Klebsiella spp.
Pharmacokinetic particulars
Cefalonium is extensively but slowly absorbed from the udder and excreted primarily in the urine. Between 7 and 13% of the active substance is eliminated in urine on each of the first three days post dosing whilst daily excretion in faeces is <1% over the same period.
Mean blood concentration remains fairly constant during approximately 10 days after dosing which is consistent with slow but prolonged absorption of cefalonium from the udder.
The long term persistence of cefalonium in the dry udder was examined over a time span of 10 weeks after infusion. Effective levels of Cefalonium in udder secreta remain up to 10 weeks after infusion.