Tetracyclines

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Tetracyclines are active against infections caused by the following:

• Rickettsiae

• Spirochetes (eg, Treponema pallidum, Borrelia burgdorferi)

• Helicobacter pylori

• Vibrio species

• Yersinia pestis

• Francisella tularensis

• Brucella species

• Bacillus anthracis

• Plasmodium vivax

• Plasmodium falciparum

• Mycoplasma species

• Chlamydia and Chlamydophila species

• Some methicillin-resistant Staphylococcus aureus

About 5 to 10% of pneumococcal strains and many group A beta-hemolytic streptococci, many gram-negative bacillary uropathogens, and penicillinase-producing gonococci are resistant.

S. aureus infections.

for all of the following because it is better tolerated and can be given twice a day:

• Infections caused by rickettsiae or Anaplasma, Chlamydia, Chlamydophila, Ehrlichia, Mycoplasma, or Vibrio species

• Acute exacerbations of chronic bronchitis

• Lyme disease

• Brucellosis

• Anthrax

• Plague

• Tularemia

• Granuloma inguinale

• Syphilis

• Prophylaxis of malariaP. falciparum

Tetracyclines are contraindicated in

• Patients who have had an allergic reaction to them

• Children < 8 years of age (except sometimes for inhalational anthrax or other severe illnesses, such as Rocky Mountain spotted fever, when the benefit outweighs the potential risk of tooth staining)

1).

Tetracyclines cross the placenta, enter fetal circulation, accumulate in fetal bones, and, if used during the 2nd or 3rd trimester, may cause permanent discoloration of the fetus's teeth.

Hepatotoxicity may occur in pregnant women, particularly after IV administration and in those with azotemia or pyelonephritis. Taking high doses during pregnancy can lead to fatty degeneration of the liver, which may be fatal.

Adverse effects of tetracyclines include

• Gastrointestinal disturbances

• Clostridioides (formerly Clostridium) difficile–induced diarrhea (pseudomembranous colitis)

• Candidiasis

• Photosensitivity

• Bone and dental effects in children

• Fatty liver

All oral tetracyclines cause nausea, vomiting, and diarrhea and can cause C. difficile–induced diarrhea (pseudomembranous colitis) and candidal superinfections. If not swallowed with water, tetracyclines can cause esophageal erosions.

Photosensitivity due to tetracyclines may manifest as an exaggerated sunburn reaction.

Bone and dental effects include staining of teeth, hypoplasia of dental enamel, and abnormal bone growth in children < 8 years and in fetuses. In infants, tetracyclines may cause idiopathic intracranial hypertension and bulging fontanelles.

Excessive blood levels due to use of high doses or renal insufficiency may lead to fatal acute fatty degeneration of the liver, especially during pregnancy.

Fanconi syndrome. Patients should be instructed to discard the drugs when they expire.

Tetracyclines may decrease the effectiveness of oral contraceptives and potentiate the effects of oral anticoagulants.