Vancomycin Hydrochloride

VANCOMYCIN HYDROCHLORIDE — vancomycin hydrochloride injection
Xellia Pharmaceuticals ApS

DESCRIPTION

Vancomycin hydrochloride for injection, USP is a lyophilized powder, for preparing intravenous (IV) infusions, in Pharmacy Bulk Package bottles containing the equivalent of 5 g or 10 g vancomycin base. 500 mg of the base are equivalent to 0.34 mmol. When reconstituted with Sterile Water for Injection to a concentration of 50 mg/mL for the 5 g Pharmacy Bulk Package bottle and 100 mg/mL for the 10 g Pharmacy Bulk Package bottle, the pH of the solution is between 2.5 and 4.5. Vancomycin hydrochloride for injection, USP should be administered intravenously in diluted solution (see DOSAGE AND ADMINISTRATION).

Vancomycin is a tricyclic glycopeptide antibiotic derived from Amycolatopasis orientalis (formerly Nocardia orientals). The chemical name for vancomycin hydrochloride is 3S-[3R*,6S*(S*),7S*,22S*,23R*,26R*,36S*,38aS*]]-3-(2-Amino-2-oxoethyl)-44-[[2-O-(3-amino-2,3,6-trideoxy-3-C-methyl-α-L-lyxo-hexopyranosyl)-ß-D-glucopyranosyl]oxy]-10,19-dichloro-2,3,4,5,6,7,23,24,25,26,36,37,38,38a-tetradecahydro-7,22,28,30,32-pentahydroxy-6-[[4-methyl-2-(methylamino)-1-oxopentyl]amino]-2,5,24,38,39-pentaoxo-22H-8,11:18,21-dietheno-23,36-(iminomethano)-13,16:31,35-dimetheno-1H,16H-[1,6,9]oxadiazacyclohexadecino[4,5-m][10,2,16]-benzoxadiazacyclotetracosine-26-carboxylic acid, monohydrochloride. The molecular formula is C66 H75 Cl2 N9 O24 • HCl and the molecular weight is 1,485.74. Vancomycin hydrochloride has the following structural formula:

structure
(click image for full-size original)

A pharmacy bulk package is a sterile dosage form containing many single doses. The contents are intended for use in a pharmacy admixture program and are restricted to the preparation of admixtures for IV infusion. AFTER RECONSTITUTION FURTHER DILUTION IS REQUIRED BEFORE USE.

CLINICAL PHARMACOLOGY

Vancomycin is poorly absorbed after oral administration.

In subjects with normal kidney function, multiple intravenous dosing of 1 g of vancomycin (15 mg/kg) infused over 60 minutes produces mean plasma concentrations of approximately 63 mcg/mL immediately after the completion of infusion, mean plasma concentrations of approximately 23 mcg/mL 2 hours after infusion, and mean plasma concentrations of approximately 8 mcg/mL 11 hours after the end of the infusion. Multiple dosing of 500 mg infused over 30 minutes produces mean plasma concentrations of about 49 mcg/mL at the completion of infusion, mean plasma concentrations of about 19 mcg/mL 2 hours after infusion, and mean plasma concentrations of about 10 mcg/mL 6 hours after infusion. The plasma concentrations during multiple dosing are similar to those after a single dose.

The mean elimination half-life of vancomycin from plasma is 4 to 6 hours in subjects with normal renal function. In the first 24 hours, about 75% of an administered dose of vancomycin is excreted in urine by glomerular filtration. Mean plasma clearance is about 0.058 L/kg/h, and mean renal clearance is about 0.048 L/kg/h. Renal dysfunction slows excretion of vancomycin. In anephric patients, the average half-life of elimination is 7.5 days. The distribution coefficient is from 0.3 to 0.43 L/kg. There is no apparent metabolism of the drug. About 60% of an intraperitoneal dose of vancomycin administered during peritoneal dialysis is absorbed systemically in 6 hours. Serum concentrations of about 10 mcg/mL are achieved by intraperitoneal injection of 30 mg/kg of vancomycin. However, the safety and efficacy of the intraperitoneal use of vancomycin has not been established in adequate and well-controlled trials (see PRECAUTIONS).

Total systemic and renal clearance of vancomycin may be reduced in the elderly. Vancomycin is approximately 55% serum protein bound as measured by ultrafiltration at vancomycin serum concentrations of 10 to 100 mcg/mL. After IV administration of vancomycin, inhibitory concentrations are present in pleural, pericardial, ascitic, and synovial fluids; in urine; in peritoneal dialysis fluid; and in atrial appendage tissue. Vancomycin does not readily diffuse across normal meninges into the spinal fluid; but, when the meninges are inflamed, penetration into the spinal fluid occurs.

MICROBIOLOGY

The bactericidal action of vancomycin results primarily from inhibition of cell-wall biosynthesis. In addition, vancomycin alters bacterial-cell-membrane permeability and RNA synthesis. There is no cross-resistance between vancomycin and other antibiotics. Vancomycin is not active in vitro against gram-negative bacilli, mycobacteria, or fungi.

Synergy

The combination of vancomycin and an aminoglycoside acts synergistically in vitro against many strains of Staphylococcus aureus , Streptococcus bovis , enterococci, and the viridans group streptococci.

Vancomycin has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.

Aerobic gram-positive microorganisms

Diphtheroids

Enterococci (e.g., Enterococcus faecalis)

Staphylococci, including Staphylococcus aureus and Staphylococcus epidermidis

(including heterogeneous methicillin-resistant strains)

Streptococcus bovis

Viridans group streptococci

The following in vitro data are available, but their clinical significance is unknown.

Vancomycin exhibits in vitro MIC’s of 1 mcg/mL or less against most (≥90%) strains of streptococci listed below and MIC’s of 4 mcg/mL or less against most (≥90%) strains of other listed microorganisms; however, the safety and effectiveness of vancomycin in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials.

Aerobic gram-positive microorganisms

Listeria monocytogenes

Streptococcus pyogenes

Streptococcus pneumoniae (including penicillin-resistant strains)

Streptococcus agalactiae

Anaerobic gram-positive microorganisms

Actinomyces species

Lactobacillus species

Susceptibility Test Methods

When available, the clinical microbiology laboratory should provide the results of in vitro susceptibility test results for antimicrobial drugs used in local hospitals and practice areas to the physician as periodic reports that describe the susceptibility profile of nosocomial and community-acquired pathogens. These reports should aid the physician in selecting the most effective antimicrobial.

Dilution Techniques

Quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (MICs). These MICs provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MICs should be determined using a standardized procedure. Standardized procedures are based on dilution method 1,2 (broth, agar or microdilution) or equivalent using standardized inoculum and concentrations of vancomycin powder. The MIC values should be interpreted according to the criteria in Table 1.

Diffusion Techniques

Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. One such standardized procedure 2,3 requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 30 mcg of vancomycin to test the susceptibility of microorganisms to vancomycin. Interpretation involves correlation of the diameter obtained in the disk test with the MIC for vancomycin. Reports from the laboratory providing results of the standard single-disk susceptibility test with a 30 mcg vancomycin disk should be interpreted according to the following criteria in Table 1.

Table 1: Susceptibility Test Interpretive Criteria for Vancomycin

Minimum InhibitoryConcentrations(mcg/mL) Disk DiffusionDiameters(mm)
Pathogen Susceptible (S) Intermediate (I) Resistant(R) Susceptible (S) Intermediate (I) Resistant (R)
Enterococci ≤4 8 to 16 a ≥32 ≥17 b 15 to 16 b ≤ 14 b
Staphylococcus aureus c,d ≤2 4 to 8 ≥16 - - -
Coagulase-negative staphylococci c,e ≤4 8 to 16 ≥32 - - -
Streptococci spp. other than S. pneumoniae ≤1 f,g - - ≥17 f,h - -

a Isolates with vancomycin MICs of 8 to 16 mcg/mL should be further screened for vancomycin resistance using standardized procedures. 1,2

b Plates should be held for a full 24 hours and examined using transmitted light. Measure the diameter of the zones of complete inhibition (as judged by the unaided eye), including the diameter of the disk. The zone margin should be considered the area showing no obvious, visible growth that can be detected with the unaided eye. Ignore faint growth of tiny colonies that can be detected only with a magnifying lens at the edge of the zone of inhibited growth. Any discernable growth within the zone of inhibition indicates vancomycin resistance. Organisms with intermediate zones should be tested by standardized dilution method.1,2

c Dilution testing should be performed to determine the susceptibility of all staphylococcal isolates. Disk diffusion testing is not reliable for testing vancomycin, as it does not differentiate vancomycin-susceptible isolates of S. aureus from vancomycin-intermediate isolates, nor does it differentiate among vancomycin-susceptible, intermediate, and resistant isolates of coagulase-negative staphylococci.2

d Any S. aureus isolate for which the vancomycin MIC is8 mcg/mL should be sent to a reference laboratory.2

e Any coagulase-negative Staphylococcus isolate for which the vancomycin MIC is32 mcg/mL, should be sent to a reference laboratory.2

f The rare occurrence of resistant isolates precludes defining any results categories other than “Susceptible”. For isolates yielding results suggestive of a nonsusceptible category, organism identification and vancomycin susceptibility test results should be confirmed. If confirmed, isolates should be sent to a reference laboratory.2

g Interpretative criteria applicable only to tests performed by broth microdilution method using cation-adjusted Mueller-Hinton broth with 2 to 5% lysed horse blood.1,2

h Interpretative criteria applicable only to tests performed by disk diffusion method using Mueller-Hinton agar with 5% defibrinated sheep blood and incubated in 5% CO2 .3

A report of “Susceptible” indicates that the pathogen is likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable. A report of “Intermediate” indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high dosage of drug can be used. This category also provides a buffer zone which prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of “Resistant” indicates that the pathogen is not likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable; other therapy should be selected.

Quality Control

Standardized susceptibility test procedures require the use of laboratory control microorganisms to monitor and ensure the accuracy and precision of the supplies and reagents used in the assay, and the techniques of the individuals performing the test. When tested against appropriate quality control strains, standard vancomycin powder should provide MIC values shown in Table 2. For the diffusion technique, the 30 mcg vancomycin disk should provide the zone diameters in Table 2 with the quality control strains:

Table 2. In vitro Susceptibility Test Quality Control Ranges for Vancomycin

Organism (ATCC#) MIC range (mcg/mL) Disk diffusion range (mm)
Enterococcus faecalis (29212) 1 to 4 Not applicable
Staphylococcus aureus (29213) 0.5 to 2 Not applicable
Staphylococcus aureus (25923)a Not applicable 17 to 21
Streptococcus pneumoniae (49619)b,c 0.12 to 0.5 20 to 27

a Quality control strain and interpretive criteria for testing vancomycin susceptibility of enterococci spp.

b Interpretative criteria applicable only to test performed using cation-adjusted Mueller–Hinton broth with 2 to 5% lysed horse blood.1 Disk diffusion interpretative criteria applicable only to tests performed using Mueller-Hinton agar with 5% defibrinated sheep blood and incubated in 5% CO2 2.

c Quality control strain and interpretive criteria for testing vancomycin susceptibility of Streptococci spp. other that S. pneumoniae.

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