Clinical Pharmacology for Cefobid
High serum and bile levels of CEFOBID are attained after a single dose of the drug. Table 1 demonstrates the serum concentrations of CEFOBID in normal volunteers following either a single 15-minute constant rate intravenous infusion of 1, 2, 3 or 4 g of the drug, or a single intramuscular injection of 1 or 2 g of the drug.
Table 1: Cefoperazone Serum Concentrations
|
Mean Serum Concentrations (mcg/mL) |
| 0* |
0.5 hr |
1 hr |
2 hr |
4 hr |
8 hr |
12 hr |
| 1 g IV |
153 |
114 |
73 |
38 |
16 |
4 |
0.5 |
| 2 g IV |
252 |
153 |
114 |
70 |
32 |
8 |
2 |
| 3 g IV |
340 |
210 |
142 |
89 |
41 |
9 |
2 |
| 4 g IV |
506 |
325 |
251 |
161 |
71 |
19 |
6 |
| 1 g IM |
32** |
52 |
65 |
57 |
33 |
7 |
1 |
| 2 g IM |
40** |
69 |
93 |
97 |
58 |
14 |
4 |
* Hours post-administration, with 0 time being the end of the infusion.
** Values obtained 15 minutes post-injection. |
The mean serum half-life of CEFOBID is approximately 2.0 hours, independent of the route of administration.
In a pharmacokinetic study, a total daily dose of 16 g was administered to severely immunocompromised patients by constant infusion without complications. Steady state serum concentrations were approximately 150 mcg/mL in these patients.
In vitro studies with human serum indicate that the degree of CEFOBID reversible protein binding varies with the serum concentration from 93% at 25 mcg/mL of CEFOBID to 90% at 250 mcg/mL and 82% at 500 mcg/mL.
CEFOBID achieves therapeutic concentrations in the following body tissues and fluids:
Table 2
| Tissue or Fluid |
Dose |
Concentration |
| Ascitic Fluid |
2 g |
64 mcg/mL |
| Cerebrospinal Fluid (in patients with inflamed meninges) |
50 mg/kg |
1.8 mcg/mL to 8.0 mcg/mL |
| Urine |
2 g |
3,286 mcg/mL |
| Sputum |
3 g |
6.0 mcg/mL |
| Endometrium |
2 g |
74 mcg/g |
| Myometrium |
2 g |
54 mcg/g |
| Palatine Tonsil |
1 g |
8 mcg/g |
| Sinus Mucous Membrane |
1 g |
8 mcg/g |
| Umbilical Cord Blood |
1 g |
25 mcg/mL |
| Amniotic Fluid |
1 g |
4.8 mcg/mL |
| Lung |
1 g |
28 mcg/g |
| Bone |
2 g |
40 mcg/g |
CEFOBID is excreted mainly in the bile. Maximum bile concentrations are generally obtained between one and three hours following drug administration and exceed concurrent serum concentrations by up to 100 times. Reported biliary concentrations of CEFOBID range from 66 mcg/mL at 30 minutes to as high as 6000 mcg/mL at 3 hours after an intravenous bolus injection of 2 g.
Following a single intramuscular or intravenous dose, the urinary recovery of CEFOBID over a 12-hour period averages 20–30%. No significant quantity of metabolites has been found in the urine. Urinary concentrations greater than 2200 mcg/mL have been obtained following a 15-minute infusion of a 2 g dose. After an IM injection of 2 g, peak urine concentrations of almost 1000 mcg/mL have been obtained, and therapeutic levels are maintained for 12 hours.
Repeated administration of CEFOBID at 12-hour intervals does not result in accumulation of the drug in normal subjects. Peak serum concentrations, areas under the curve (AUC's), and serum half-lives in patients with severe renal insufficiency are not significantly different from those in normal volunteers. In patients with hepatic dysfunction, the serum half-life is prolonged and urinary excretion is increased. In patients with combined renal and hepatic insufficiencies, CEFOBID may accumulate in the serum.
CEFOBID has been used in pediatrics, but the safety and effectiveness in children have not been established. The half-life of CEFOBID in serum is 6–10 hours in low birth-weight neonates.
Microbiology
Mechanism Of Action
Cefoperazone, a third-generation cephalosporin, interferes with cell wall synthesis by binding to the penicillin-binding proteins (PBPs), thus preventing cross-linking of nascent peptidoglycan.
Resistance
There are 3 principal mechanisms of resistance to cefoperazone: mutations in the target PBPs, which occur primarily in gram-positive bacteria; production of extended spectrum beta-lactamases or over-expression of chromosomally determined beta-lactamases in gram-negative bacteria; reduced uptake or active efflux in certain gram-negative bacteria.
Interactions With Other Antimicrobials
When tested in vitro, cefoperazone has demonstrated synergistic interactions with aminoglycosides against gram-negative bacilli. The clinical significance of these in vitro findings is unknown.
Antimicrobial Activity
Cefoperazone has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections (see INDICATIONS AND USAGE).
Aerobic Bacteria
Gram-Positive Bacteria
Staphylococcus aureus (methicillin-susceptible isolates only)
Staphylococcus epidermidis (methicillin-susceptible isolates only)
Streptococcus agalactiae (Group B beta-hemolytic streptococci)
Streptococcus pneumoniae
Streptococcus pyogenes (Group A beta-hemolytic streptococci)
Gram-Negative Bacteria
Citrobacter species
Enterobacter species
Escherichia coli
Haemophilus influenzae
Klebsiella species
Morganella morganii
Neisseria gonorrhoeae
Proteus mirabilis
Proteus vulgaris
Providencia rettgeri
Providencia stuartii
Pseudomonas species
Serratia marcescens
Anaerobic Bacteria
Gram-positive cocci (including Peptococcus and Peptostreptococcus spp.)
Clostridioides species
Bacteroides species
The following in vitro data are available, but their clinical significance is unknown. At least 90% of the following bacteria exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the susceptible breakpoint for cefoperazone against isolates of similar genus or organism group. However, the efficacy of cefoperazone in treating clinical infections due to these bacteria has not been established in adequate and well-controlled clinical trials.
Aerobic Bacteria
Gram-Negative Bacteria
Bordetella pertussis
Neisseria meningitidis
Salmonella spp.
Serratia liquefaciens
Shigella spp.
Yersinia enterocolytica
Anaerobic Bacteria
Eubacterium spp.
Fusobacterium spp.
Susceptibility Test Methods
For specific information regarding susceptibility test interpretive criteria, and associated test methods and quality control standards recognized by FDA for this drug, please see https://www.fda.gov/STIC.