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Tetracyclines

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The tetracyclines (see Table 13: Bacteria and Antibacterial Drugs: TetracyclinesTables) are bacteriostatic antibiotics that bind to the 30S subunit of the ribosome, thus inhibiting bacterial protein synthesis.

Table 13

Tetracyclines

Doxycycline Some Trade Names
PERIOSTAT
VIBRAMYCIN
Click for Drug Monograph

Minocycline Some Trade Names
MINOCIN
Click for Drug Monograph

Tetracycline Some Trade Names
ACHROMYCIN V
TETRACYN
TETREX
Click for Drug Monograph

Pharmacology: About 60 to 80% of tetracycline Some Trade Names
ACHROMYCIN V
TETRACYN
TETREX
Click for Drug Monograph
and 90% of doxycycline Some Trade Names
PERIOSTAT
VIBRAMYCIN
Click for Drug Monograph
and minocycline Some Trade Names
MINOCIN
Click for Drug Monograph
are absorbed after oral administration. Because absorption is decreased by metallic cations (eg, aluminum, Ca, Mg, and iron), tetracyclines cannot be taken with preparations containing these substances (eg, antacids, many vitamin and mineral supplements). Food decreases absorption of tetracycline Some Trade Names
ACHROMYCIN V
TETRACYN
TETREX
Click for Drug Monograph
but not of doxycycline Some Trade Names
PERIOSTAT
VIBRAMYCIN
Click for Drug Monograph
or minocycline Some Trade Names
MINOCIN
Click for Drug Monograph
.

Tetracyclines penetrate into most body tissues and fluids. All are concentrated in unobstructed bile. However, CSF levels are not reliably therapeutic. Minocycline Some Trade Names
MINOCIN
Click for Drug Monograph
is the only tetracycline Some Trade Names
ACHROMYCIN V
TETRACYN
TETREX
Click for Drug Monograph
that penetrates into tears and saliva in levels sufficient to eradicate the meningococcal carrier state. Tetracycline Some Trade Names
ACHROMYCIN V
TETRACYN
TETREX
Click for Drug Monograph
and minocycline Some Trade Names
MINOCIN
Click for Drug Monograph
are excreted primarily in the urine, may exacerbate azotemia, and should be avoided in patients with renal insufficiency. In renal failure, doxycycline Some Trade Names
PERIOSTAT
VIBRAMYCIN
Click for Drug Monograph
is primarily excreted in the intestinal tract and requires no dose reduction. Tetracyclines cross the placenta to accumulate in fetal bones and teeth and are excreted in milk.

Indications: Tetracyclines are effective in infections caused by rickettsiae, spirochetes (Treponema pallidum , Borrelia burgdorferi), Helicobacter pylori , Vibrio sp, Yersinia pestis , Francisella tularensis , Brucella sp, Bacillus anthracis , Plasmodium vivax , Plasmodium falciparum , Mycoplasma, and Chlamydia and Chlamydophila. About 5 to 10% of pneumococcal strains and substantial numbers of group A β-hemolytic streptococci, many gram-negative bacillary uropathogens, and penicillinase-producing gonococci are resistant.

Tetracyclines are interchangeable for most indications, although minocycline Some Trade Names
MINOCIN
Click for Drug Monograph
has been most studied for methicillin-resistant Staphylococcus aureus infections. Doxycycline Some Trade Names
PERIOSTAT
VIBRAMYCIN
Click for Drug Monograph
is usually preferred because of its better tolerability and twice-daily administration for infections caused by rickettsiae, Chlamydia and Chlamydophila , Mycoplasma, and Vibrio sp; acute exacerbations of chronic bronchitis; Lyme disease; brucellosis; anthrax; plague; tularemia; granuloma inguinale; and syphilis. Doxycycline Some Trade Names
PERIOSTAT
VIBRAMYCIN
Click for Drug Monograph
is used for prophylaxis of malaria caused by chloroquine Some Trade Names
ARALEN
Click for Drug Monograph
-resistant P. falciparum. Minocycline Some Trade Names
MINOCIN
Click for Drug Monograph
is an alternate to rifampin Some Trade Names
RIFADIN
RIMACTANE
Click for Drug Monograph
for eradicating the meningococcal carrier state.

Toxicity: All orally administered tetracyclines produce nausea, vomiting, and diarrhea and can cause Clostridium difficile colitis and Candida superinfections. They can cause esophageal erosions if not swallowed with water. Tetracyclines can cause photosensitivity. They can cause staining of teeth, hypoplasia of dental enamel, and abnormal bone growth in children 8 yr and in fetuses. Therefore, tetracyclines should be avoided after the 1st trimester of pregnancy, in mothers who are breastfeeding, and in children < 8 yr. In infants, idiopathic intracranial hypertension and bulging fontanelles may occur.

Excessive blood levels from large doses or renal insufficiency may lead to fatal acute fatty degeneration of the liver, especially during pregnancy. Minocycline Some Trade Names
MINOCIN
Click for Drug Monograph
commonly causes vestibular dysfunction, particularly in women, limiting its use. Tetracyclines may decrease the efficacy of oral contraceptives and potentiate the effects of oral anticoagulants.

Older formulations of expired tetracycline Some Trade Names
ACHROMYCIN V
TETRACYN
TETREX
Click for Drug Monograph
pills can degenerate, causing Fanconi syndrome if ingested.

Last full review/revision November 2005

Content last modified November 2005

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