Ixime Mechanism of Action





Full Prescribing Info
Pharmacology: Pharmacokinetics: Cefixime given orally are about 40-50% absorbed whether administered with or without food, however, time to maximal absorption is increased approximately 0.8 hours when administered with food.
The oral suspension produced an average peak concentration approximately 25-50% higher than the tablets, when tested in normal adult volunteers.
200 and 400 mg doses of the oral suspension produced average peak concentrations of 3 μg/ml (range of 1 to 4.5 μg/ml) and 4.6 μg/ml (range of 1.9 to 7.7 μg/ml) respectively when tested in normal adult volunteers.
The area under the Time versus Concentration Curve is greater by approximately 10% - 25% with the oral suspension than with the tablet after doses of 100 to 400 mg in normal adult volunteers.
This increased absorption should be taken into consideration if the oral suspension is to be substituted for the tablet.
Tablets should not be substituted for oral suspension in the treatment of Otitis media because of the lack of bioequivalence.
Cross over studies of tablet versus suspension have not been performed in children.
Peak serum concentrations occur between 2 and 6 hours following the administration of a single 200 mg Tablet or a single 400 mg tablet. (See Tables 1 and 2.)

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Oral susp: Peak serum concentrations occur between 2 and 6 hours following oral administration of 400 mg of Cefixime suspension.
Peak serum concentrations occur between 2 and 5 hours following a single administration of 200 mg of suspension. (See Table 3.)

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Approximately 50% of the absorbed dose is excreted unchanged in the urine in 24 hours.
In animal studies it was noted that Cefixime is also excreted in the bile in excess of 10% of the administered dose.
Serum protein binding is concentration independent with a bound fraction of approximately 65%.
Cefixime is almost exclusively bound to the albumin fraction, the mean free fraction being approximately 30%.
Protein binding of Cefixime is only concentration dependent in human serum at very high concentrations which are not seen following clinical dosing.
In a multiple dose study conducted with a research formulation which was less bioavailable than the tablet or suspension, there was little accumulation of drug in serum or urine after dosing for 14 days.
The serum half-life of Cefixime in healthy subjects is independent of dosage form and averages 3 to 4 hours but may range up to 9 hours in some normal volunteers.
Average AUCs at steady state in elderly patients are approximately 40% higher than average AUCs in other healthy adults.
In subjects with moderate impairment of renal function (20 to 40 mL/min Creatinine Clearance), the average serum half-life of Cefixime is prolonged to 6.4 hours.
In severe renal impairment (5 to 20 mL/min Creatinine Clearance), the half-life increased to an average of 11.5 hours.
Cefixime is predominantly eliminated as the unchanged drug in the urine.
Glomerular filtration is the predominant mechanism of elimination and metabolites have not been isolated either from human serum or urine.
Cefixime is not cleared significantly from the blood by hemodialysis or peritoneal dialysis.
However, a study indicated that with doses of 400 mg, patients undergoing hemodialysis have similar blood profiles as subjects with Creatinine Clearances of 21-60 mL/min.
There is no evidence of metabolism of Cefixime in vivo.
Adequate data on CSF levels of Cefixime are not available.
FC tab: A single 200 mg tablet of Cefixime produced an average peak serum concentration of approximately 2 μg/ml (range of 1 to 4 μg/ml) where as a single 400 mg tablet produced an average peak concentration of approximately 3.7μg/ml (range of 1.3 to 7.7 μg/ml).
Toxicology: FC tab: Carcinogenesis, mutagenesis, impairment of fertility: Cefixime did not cause point mutations in bacteria or mammalian cells, damage to DNA and chromosomes in vitro and did not exhibit clastogenic potential in vivo in the mouse micronucleus test.
Cefixime did not affect fertility and reproductive performance in rats at doses upto 125 times the adult therapeutic dose.
Microbiology: The bactericidal action of Cefixime, as with other Cephalosporins results from inhibition of cell wall synthesis. Cefixime is highly stable in the presence of β lactamase enzymes.
As a result, many organisms resistant to Penicillins and some Cephalosporins due to the presence of β lactamases, may be susceptible to Cefixime.
Cefixime has been shown to be active against most strains of the following organisms both in vitro and in clinical infections.
Gram-positive organisms: Streptococcus pneumoniae, Streptococcus pyogenes.
Gram-negative organisms: Haemophilus influenzae (β lactamase positive & negative strains), Moraxella catarrhalis (mostly β lactamase positive), Escherichia coli, Proteus mirabilis, Salmonella typhi, Neisseria gonorrhoeae (including Penicillinase & Non Penicillinase Producing strains).
CEFIXIME has been shown to be active in vitro against most strains of the following organisms, however, clinical efficacy has not been established.
Gram-positive organisms: Streptococcus agalactiae.
Gram-negative organisms: Haemophilus parainfluenzae (β lactamase positive & negative strains), Proteus vulgaris, Klebsiella pneumoniae, Klebsiella oxytoca, Pasteurella multocida, Providencia species, Shigella species, Citrobacter amalonaticus, Citrobacter diversus, Serratia marcescens.
Note: Pseudomonas species, strains of group D Streptococci (including Enterococci), Listeria monocytogenes, most strains of Staphylococci (including Methicillin Resistant Strains) and most strains of Enterobacter are resistant to Cefixime.
In addition, most strains of Bacteroides fragilis and Clostridia are resistant to Cefixime.
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