antibioticsbooks

106 PART 2 Antibacterial Drugs
Spectrum: tetracycline/doxycycline/
minocycline
Good: atypicals, rickettsia, spirochetes (e.g., B.
burgdorferi, Helicobacter pylori), Plasmo dium
species (malaria)
Moderate: staphylococci (including MRSA), S.
pneumoniae
Poor: most GNRs, anaerobes, enterococci
Spectrum: tigecycline
Good: atypicals, enterococci (including VRE),
staph ylococci (including MRSA), S. pneumoniae
Acceptable: most GNRs, anaerobes
Poor: Pseudomonas, Proteus, Providencia
Adverse Effects
Gastrointestinal: Tetracyclines can cause esophageal
irritation, and patients should take the
drug with water, while standing up if possible.
Tigecycline, though an IV drug, can cause
severe nausea, vomiting, and diarrhea.
Dermatologic: Photosensitivity is often seen.
Patients should avoid the sun or use sunscreen
while taking tetracyclines.
Sensory: Minocycline may cause dizziness and
vertigo.
Developmental: All tetracyclines can cause discoloration
of developing teeth and are contraindicated
in pregnant women and children younger
than 8 years old.
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Important Facts
• Doxycycline and minocycline bioavailability is
approximately 100%. Tigecycline is IV only.
• Tetracyclines chelate cations, and their oral
bioavailability is decreased significantly when