Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2017 Publisher: Villerton Invest SA, Rue Edward Steichen 14, 2540 Luxembourg
Pharmacotherapeutic group: Beta-lactam antibiotics, cephalosporins
ATC Code: J01DD01
Cefotaxime exerts its action by binding to one or more of the penicillin-binding proteins (PBPs) which in turn inhibits the final transpeptidation step of peptidoglycan synthesis in bacterial cell walls, thereby inhibiting cell wall synthesis.
Resistance to Cefotaxime may be due to one or several of the following mechanisms:
More than one of these mechanisms may co-exist in a single bacterium.
Efficacy mainly depends on time above the minimal inhibitory concentration of cefotaxime for the pathogen(s) to be treated (T/MIC).
Current MIC breakpoints used to interpret cefotaxime susceptibility data are shown below.
European Committee on Antimicrobial Susceptibility Testing (EUCAST) Clinical MIC Breakpoints (V1.1, 31/03/2006):
| Susceptible (< ) / Resistant (> ) | |
|---|---|
| Enterobacteriaceae2 | 1/2 |
| Pseudomonas | -- |
| Acinetobacter | -- |
| Staphylococcus3 | Note3 |
| Enterococcus | -- |
| Streptococcus A, B, C, G | 0.5/0.54 |
| Streptococcus pneumoniae | 0.5/24 |
| Haemophilus influenzae | 0.12/0.124 |
| Moraxella Catarrhalis | |
| Neisseria gonorrhoea | 0.12/0.124 |
| Neisseria Meningitidis | 0.12/0.124 |
| Gram-negative, anaerobes | -- |
| Non-species related breakpoints1 | 1/2 |
| S≤ / >R |
^16 Non-species related breakpoints have been determined mainly on the basis of PK/PD data and are independent of MIC distributions of specific species. They are for use only for species that have not been given a species-specific breakpoint and not for those species where susceptibility testing is not recommended (marked with — or IE in the table).
2 The cephalosporin breakpoints for Enterobacteriaceae will detect resistance mediated by most ESBLs and other clinically important beta-lactamases in Enterobacteriaceae. However, some ESBL-producing strains may appear susceptible or intermediate with these breakpoints. Laboratories may want to use a test which specifically screens for the presence of ESBL.
3 Susceptibility of staphylococci to cephalosporins is inferred from the methicillin susceptibility (except ceftazidime which should not be used for staphylococcal infections).
4 Strains with MIC values above the S/I breakpoint are very rare or not yet reported. The identification and antimicrobial susceptibility tests on any such isolate must be repeated and if the result is confirmed the isolate sent to a reference laboratory. Until there is evidence regarding clinical response for confirmed isolates with MIC above the current resistant breakpoint (in italics) they should be reported resistant.
-- = Susceptibility testing not recommended as the species is a poor target for therapy with the drug.
IE = There is insufficient evidence that the species in question is a good target for therapy with the drug.
RD = rationale document listing data used by EUCAST for determining breakpoints.
Gram-positive aerobes:
Staphylococcus aureus (Methicillin-susceptible)^*
Group A Streptococci (including Streptococcus pyogenes) *
Group B Streptococci
β-hemolytic Streptococci (Group C, F, G)
Viridans Group Streptococci
Gram-negative aerobes:
Haemophilus influenzae*
Haemophilus parainfluenzae *
Moraxella catarrhalis*
Neisseria gonorrhoeae *
Neisseria meningitides *
Proteus spp. *
Providencia spp. *
Yersinia enterocolitica
Anaerobes:
Clostridium spp. (not Clostridium difficile)
Peptostreptococcus spp.
Propionibacterium spp.
Others:
Species for which acquired resistance may be a problem:
Streptococcus pneumoniae
Citrobacter spp*
Enterobacter spp*
Klebsiella spp*
Escherichia coli*
Serratia spp
Morganella morganii
Streptococcus pneumoniae*
Gram-positive aerobes:
Enterococcus spp.
Enterococcus faecalis
Enterococcus faecium
Listeria spp.
Gram-negative aerobes:
Acinetobacter spp.
Pseudomonas spp.
Stenotrophomonas maltophilia
Anaerobes:
Bacteroides spp.
Clostridium difficile
Others:
Chlamydiae
Mycoplasma spp.
Legionella pneumophilia
* Clinical efficacy has been demonstrated for susceptible isolates in approved clinical indications.
^ Methicillin-(oxacillin) resistant staphylococci (MRSA) are always resistant to cefotaxime.
Penicillin-resistant Streptococcus pneumoniae show a variable degree of resistance to cephalosporins such as cefotaxime.
After a 1000 mg intravenous bolus, mean peak plasma concentrations of cefotaxime usually range between 81 and 102 microgram/ml. Doses of 500 mg and 2000 mg produce plasma concentrations of 38 and 200 microgram /ml, respectively. There is no accumulation following administration of 1000 mg intravenously or 500 mg intramuscularly for 10 or 14 days.
The apparent volume of distribution at steady-state of cefotaxime is 21.6 litres/1.73 m² after 1 g intravenous 30 minute infusion.
Concentrations of cefotaxime (usually determined by non-selective assay) have been studied in a wide range of human body tissues and fluids. Cerebrospinal fluid concentrations are low when the meninges are not inflamed, but are between 3 and 30 microgram/ml in children with meningitis. Cefotaxime usually passes the blood-brain barrier at levels above the MIC of common sensitive pathogens when the meninges are inflamed. Concentrations (0.2-5.4 microgram/ml), inhibitory for most Gram-negative bacteria, are attained in purulent sputum, bronchial secretions and pleural fluid after doses of 1 or 2 g. Concentrations likely to be effective against most sensitive organisms are similarly attained in female reproductive organs, otitis media effusions, prostatic tissue, interstitial fluid, renal tissue, peritoneal fluid and gall bladder wall, after usual therapeutic doses. High concentrations of cefotaxime and desacetyl-cefotaxime are attained in bile.
Cefotaxime is partially metabolised prior to excretion. The principal metabolite is the microbiologically active product, desacetyl-cefotaxime. Most of a dose of cefotaxime is excreted in the urine about 60% as unchanged drug and a further 24% as desacetyl-cefotaxime. Plasma clearance is reported to be between 260 and 390 ml/minute and renal clearance 145 to 217 ml/minute.
After intravenous administration of cefotaxime to healthy adults, the elimination half-life of the parent compound is 0.9 to 1.14 hours and that of the desacetyl metabolite, about 1.3 hours.
In neonates the pharmacokinetics are influenced by gestational and chronological age, the half-life being prolonged in premature and low birth weight neonates of the same age.
In severe renal dysfunction the elimination half-life of cefotaxime itself is increased minimally to about 2.5 hours, whereas that of desacetyl-cefotaxime is increased to about 10 hours. Total urinary recovery of cefotaxime and its principal metabolite decreases with reduction in renal function.
There are no preclinical data of relevance to the prescriber which are additional to the data already provided in other sections of this Summary of Product Characteristics.
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