III. Contraindications

  1. Pregnancy
    1. Pregnancy category D
  2. Children under age 8 years old
    1. AAP now approves Doxycycline for ANY age up to 21 day duration
    2. Unlike Tetracycline, Doxycycline is unlikely to cause visible tooth staining
    3. For severe infections (e.g. Lyme Disease, Rocky Mountain Spotted Fever), Doxycycline is a first-line agent

IV. Mechanism

  1. See Tetracycline
  2. Tetracyclines are bacteriostatic Protein synthesis inhibitors, binding the 30S ribosomal subunit of susceptible Bacteria
  3. Prevents elongated peptide chains from forming from Amino Acid residues
    1. Inhibits Amino Acid-linked tRNA from binding at the Ribosomal A Site

V. Dosing

  1. Acne Vulgaris
    1. Take 1 gram divided two to four times orally daily

VI. Pharmacokinetics

  1. Does not penetrate CSF
  2. Concentrated by the liver via enterohepatic circulation
  3. Excreted in urine and stool

VII. Precautions

  1. Use Sunscreen with these agents due to Drug-induced Photosensitivity
  2. Pill Esophagitis
    1. Take with a full glass of water

VIII. Adverse Effects

  1. Photosensitivity
  2. Interferes with OCP action
  3. Tooth Discoloration (Children under age 8 years)
    1. Tooth enamel hypoplasia
    2. Rare with Doxycycline
  4. Pseudotumor Cerebri
    1. Rare Tetracycline class effect

IX. Safety

  1. Pregnancy Category D
  2. Unknown safety in Lactation

X. Drug Interactions

  1. Food
    1. Milk and Calcium-rich food decrease absorption
    2. Take 1 hour before or 2 hours after a meal
    3. Take with a full glass of water (risk of Pill Esophagitis)
  2. Warfarin
    1. Increases INR

XII. References

  1. (2019) Tarascon Pharmacopeia, accessed 3/31/2019
  2. LoVecchio (2019) Crit Dec Emerg Med 33(3): 28

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Related Studies

Cost: Medications

tetracycline (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
TETRACYCLINE 250 MG CAPSULE Generic $0.66 each
TETRACYCLINE 500 MG CAPSULE Generic $0.95 each