Recommended Topic Related To:

Minocin Injection

"The U.S. Food and Drug Administration today approved Dotarem (gadoterate meglumine) for use in magnetic resonance imaging (MRI) of the brain, spine and associated tissues of patients ages 2 years and older.

Dotarem is a gadolinium-based"...

Minocin Injection

CLINICAL PHARMACOLOGY

Following a single dose of Minocin 200 mg administered intravenously to 10 healthy male subjects, serum concentrations of minocycline ranged from 2.52 to 6.63 mcg/mL (average 4.18 mcg/mL) at the end of infusion and 0.82 to 2.64 mcg/mL (average 1.38 mcg/mL) after 12 hours. In a group of 5 healthy male subjects, serum concentrations of minocycline ranged from 1.4 to 1.8 mcg/mL at the end of the dosing interval following administration of Minocin 100 mg every 12 hours for three days. When Minocin 200 mg once daily was administered for three days, serum concentrations of minocycline were approximately 1 mcg/mL at 24 hours. The serum elimination half-life of minocycline following administration of either Minocin 100 mg every 12 hours or 200 mg once daily was not significantly different and ranged from 15 to 23 hours.

The serum elimination half-life of minocycline ranged from 11 to 16 hours in subjects with hepatic impairment (n=7) and 18 to 69 hours in subjects with renal impairment (n=5). In comparison, the serum elimination half-life of minocycline ranged from 11 to 17 hours following a single dose of oral minocycline 200 mg in healthy subjects (n=12).

Microbiology

The tetracyclines are primarily bacteriostatic and are thought to exert their antimicrobial effect by the inhibition of protein synthesis. The tetracyclines, including minocycline, have a similar antimicrobial spectrum of activity against a wide range of Gram-positive and Gram-negative bacteria. Cross-resistance of these bacteria to tetracyclines is common.

Minocycline has been shown to be active against most isolates of the following bacteria, both in vitro and in clinical infections as described in the INDICATIONS section:

Gram-Positive Bacteria

Because many isolates of the following Gram-positive bacteria have been shown to be resistant to tetracyclines, culture and susceptibility testing are especially recommended.

Bacillus anthracis1
Listeria monocytogenes
1
Staphylococcus aureus

Streptococcus pneumoniae

Gram-Negative Bacteria

Bartonella bacilliformis
Brucella species

Klebsiella (Calymmatobacterium) granulomatis

Campylobacter fetus

Francisella tularensis

Vibrio cholerae

Yersinia pestis

Because many isolates of the following Gram-negative bacteria have been shown to be resistant to tetracyclines, culture and susceptibility testing are especially recommended.

Acinetobacter species
Enterobacter aerogenes

Escherichia coli

Haemophilus influenzae

Klebsiella species

Neisseria meningitidis
1
Shigella species

"Other" Microorganisms

Actinomyces species1
Borrelia recurrentis

Chlamydia psittaci

Chlamydia trachomatis

Clostridium species
1
Entamoeba species

Fusobacterium nucleatum subspecies fusiforme
1
Mycobacterium marinum

Mycoplasma pneumoniae

Propionibacterium acnes

Rickettsiae

Treponema pallidum subspecies pallidum
1
Treponema pallidum subspecies pertenue

Ureaplasma urealyticum

Susceptibility Tests

When available, the clinical microbiology laboratory should provide the results of in vitro susceptibility test results for antimicrobial drugs used in resident hospitals 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 an antibacterial drug for treatment.*

Broth microdilution and agar dilution susceptibility testing should be performed with tetracycline except when testing Neisseria meningitidis (see below) since it predicts susceptibility to minocycline. However, certain bacteria (e.g. Acinetobacter species) may be more susceptible to minocycline and doxycycline than to tetracycline.

Dilution techniques

Quantitative methods are used to determine antimicrobial minimal 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 a dilution method1,3 (broth or agar) or equivalent with standardized inoculum concentrations and standardized concentrations of tetracycline powder (Note: minocycline powder should be used for testing Neisseria meningiditis). The MIC values should be interpreted according to the following criteria:

For Enterobacteriaceae, Acinetobacter species, Staphylococcus aureus, and Vibrio cholerae

MIC (µg/mL) Interpretation
≤ 4.0 Susceptible (S)
8.0 Intermediate (I)
≥ 16.0 Resistant (R)

For Haemophilus influenzae and Streptococcus pneumoniae

MIC (µg/mL) Interpretation
≤ 2.0 Susceptible (S)
4.0 Intermediate (I)
≥ 8.0 Resistant (R)

For Neisseria meningiditis (use minocycline powder for testing)

MIC (mcg/mL) Interpretation
≤ 2.0 Susceptible (S)

For Bacillus anthracis

MIC (mcg/mL) Interpretation
≤ 1.0 Susceptible (S)

For Francisella tularensis

MIC (mcg/mL) Interpretation
≤ 4.0 Susceptible (S)

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.

Standardized susceptibility test procedures require the use of laboratory control bacteria to control the technical aspects of the laboratory procedures. Standard tetracycline powder should provide the following MIC values:

Microorganism MIC Range (µg/mL)
Escherichia coli ATCC 25922 0.5-2.0
Haemophilus influenzae ATCC 49247 4-32
Staphylococcus aureus ATCC 29213 0.06-0.5
Streptococcus pneumoniae ATCC 49619 0.12-0.5

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 procedure2,3 requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 30 meg tetracycline (class disk) or 30 meg minocycline to test the susceptibility of bacteria to minocycline.

Reports from the laboratory providing results of the standard single-disk susceptibility test with a 30 mcg tetracycline or 30 mcg minocycline disk should be interpreted according to the following criteria:

For Enterobacteriaceae and Acinetobacter species with tetracycline disk

Zone Diameter (mm) Interpretation
≥ 15 Susceptible (S)
12-14 Intermediate (I)
≤ 11 Resistant (R)

For Enterobacteriaceae and Acinetobacter species with minocycline disk

Zone Diameter (mm) Interpretation
≥ 16 Susceptible (S)
13-15 Intermediate (I)
≤ 12 Resistant (R)

For Haemophilus influenzae with tetracycline disk

Zone Diameter (mm) Interpretation
≥ 29 Susceptible (S)
26-28 Intermediate (I)
≤ 25 Resistant (R)

For Streptococcus pneumoniae with tetracycline disk

Zone Diameter (mm) Interpretation
≥ 23 Susceptible (S)
19-22 Intermediate (I)
≤ 18 Resistant (R)

For Staphylococcus aureus and Vibrio cholerae with tetracycline disk

Zone Diameter (mm) Interpretation
≥ 19 Susceptible (S)
15-18 Intermediate (I)
≤ 14 Resistant (R

For Neisseria meningitidis with minocycline disk

Zone Diameter (mm) Interpretation
≥ 26 Susceptible (S)

As with standardized dilution techniques, diffusion methods require the use of laboratory control bacteria that are used to control the technical aspects of the laboratory procedures. For the diffusion technique, the 30 meg tetracycline disk or 30 meg minocycline disk should provide the following zone diameters in these laboratory test quality control strains:

Microorganism Zone Diameter Range (mm)
Tetracycline Minocycline
Escherichia coli ATCC 25922 18-25 19-25
Haemophilus influenzae ATCC 49247 14-22 -------
Staphylococcus aureus ATCC 259233 24-30  
Streptococcus pneumoniae ATCC 49619 27-31 -------

Animal Pharmacology And Toxicology

Minocycline hydrochloride has been observed to cause a dark discoloration of the thyroid in experimental animals (rats, minipigs, dogs, and monkeys). In the rat, chronic treatment with minocycline hydrochloride has resulted in goiter accompanied by elevated radioactive iodine uptake and evidence of thyroid tumor production. Minocycline hydrochloride has also been found to produce thyroid hyperplasia in rats and dogs.

REFERENCES

1. When penicillin is contraindicated, tetracyclines are alternative drugs in the treatment of infections caused by the cited bacteria.

1. Clinical and Laboratory Standards (CLSI). Methods for Dilution Susceptibility Tests for Bacteria that Grow Aerobically; Approved Standard - 8th ed. CLSI document M07-A8. CLSI, 940 West Valley Rd., Suite 1400, Wayne, PA 19087-1898, 2009

2. CLSI. Performance Standards for Antimicrobial Disk Susceptibility Tests; Approved Standard-lOth ed. CLSI document M02-A10, 2009.

3. CLSI. Performance Standards for Antimicrobial Susceptibility Testing; 19th Informational supplement. CLSI document M100-S19, 2009.

Last reviewed on RxList: 10/18/2010
This monograph has been modified to include the generic and brand name in many instances.

A A A

Report Problems to the Food and Drug Administration

 

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.


Women's Health

Find out what women really need.