Minocycline hydrochloride capsules are rapidly absorbed from the gastrointestinal tract following oral administration. Following a single dose of two 100 mg capsules of minocycline HCl administered to 18 normal fasting adult volunteers, maximum serum concentrations were attained in 1 to 4 hours (average 2.1 hours) and ranged from 2.1 to 5.1 mcg/mL (average 3.5 mcg/mL). The serum half-life in the normal volunteers ranged from 11.1 to 22.1 hours (average 15.5 hours).

When minocycline hydrochloride capsules were given concomitantly with a meal which included dairy products, the extent of absorption of minocycline hydrochloride capsules was not noticeably influenced. The peak plasma concentrations were slightly decreased (11.2%) and delayed by one hour when administered with food, compared to dosing under fasting conditions.

In previous studies with other minocycline dosage forms, the minocycline serum half-life ranged from 11 to 16 hours in 7 patients with hepatic dysfunction, and from 18 to 69 hours in 5 patients with renal dysfunction. The urinary and fecal recovery of minocycline when administered to 12 normal volunteers is one-half to one-third that of other tetracyclines.

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 similar antimicrobial spectra of activity against a wide range of gram-positive and gram-negative organisms. Cross-resistance of these organisms to tetracyclines is common.

While in vitro studies have demonstrated the susceptibility of most strains of the following microorganisms, clinical efficacy for infections other than those included in the INDICATIONS AND USAGE section has not been documented.

Gram-Negative Bacteria:

• Bartonella bacilliformis
• Brucella species
• Calymmatobacterium granulomatis
• Campylobacter fetus
• Francisella tularensis
• Haemophilus ducreyi
• Haemophilus influenzee
• Listeria monocytogenes
• Neisseria gonorrhoeae
• Vibrio cholerae
• Yersinia pestis

Because many strains of the following groups of gram-negative microorganisms have been shown to be resistant to tetracyclines, culture and susceptibility tests are especially recommended:

• Acinetobacter species
• Bacteroides species
• Enterobacter aerogenes
• Escherichia coli
• Klebsiella species
• Shigella species

Gram-Positive Bacteria: Because many strains of the following groups of gram-positive microorganisms have been shown to be resistant to tetracyclines, culture and susceptibility testing are especially recommended. Up to 44 percent of Streptococcus pyogenes strains have been found to be resistant to tetracycline drugs. Therefore, tetracyclines should not be used for streptococcal disease unless the organism has been demonstrated to be susceptible.

• Enterococcus group [Enterococcus faecalis (formerly Streptacoccus faecalis) and Enterococcus facium (formerly Streptococcus faecium)]
• Streptococcus pneumoniae
• Streptococcus pyogenes
• Viridans group streptococci

Bookmark this page: