Antimicrobials
Doxycycline

Doxycycline

Low
Excellent (90 to 100%)
See Additional Information

Spectrum of Activity

Dosing

General Information

  • GI upset

  • Erosive esophagitis

  • Photosensitivity rash

  • Teeth staining

  • Vulvovaginal candidiasis

  • Antacids: 
    • May decrease the absorption of Tetracyclines
    • Management: Separate administration of antacids and oral tetracycline derivatives by several hours when possible to minimize the extent of this potential interaction
  • Bismuth Subcitrate: 
    • May decrease the serum concentration of Tetracyclines
    • Management: Avoid administration of oral tetracyclines within 30 minutes of bismuth subcitrate administration
      • This is of questionable significance for at least some regimens intended to treat H. pylori infections.
  • Bismuth Subsalicylate: 
    • May decrease the serum concentration of Tetracyclines
    • Management: Consider dosing tetracyclines 2 hours before or 6 hours after bismuth
      • The need to separate doses during Helicobacter pylori eradication regimens is questionable.
  • Divalent and Polyvalent Cations (Calcium, Magnesium, Zinc, Iron): 
    • May decrease the absorption of tetracyclines
    • Of concern only with oral administration of both agents
    • Management: Consider administering the oral cation at least 2 hours before or 4 hours after the dose of tetracycline
  • CarBAMazepine: 
    • May decrease the serum concentration of Doxycycline
    • Management: Consider increasing the doxycycline dose, or using another tetracycline derivative due to the potential for reduced doxycycline therapeutic effects when coadministered wth carbamazepine
  • Iron Preparations: 
    • Tetracyclines may decrease the absorption of Iron Preparations
    • Iron Preparations may decrease the serum concentration of Tetracyclines
    • Management: Avoid this combination if possible. Administer oral iron preparations at least 2 hours before, or 4 hours after, the dose of the oral tetracycline derivative
  • Sucralfate: 
    • May decrease the absorption of Tetracyclines
    • Management: Administer most tetracycline derivatives at least 2 hours prior to sucralfate in order to minimize the impact of this interaction

Vibramycin

Cost:

  • PO: $ (<$25/day)

  • IV: $$ ($26-$100/day)

  • Absorption: Oral: 
    • Almost completely absorbed from the GI tract
    • Peak plasma concentration may be reduced ~20% by high-fat meal or milk
  • Distribution
    • Widely into body tissues and fluids including synovial, pleural, prostatic, seminal fluids, and bronchial secretions
    • Saliva, aqueous humor and CSF penetration is poor
  • Protein Binding: >90%
  • Metabolism
    • Not hepatic
    • Partially inactivated in GI tract by chelate formation
  • Bioavailability
    • Reduced at high pH
    • May be clinically significant in patients with gastrectomy, gastric bypass surgery or who are otherwise deemed achlorhydric
  • Half-Life Elimination: 18-22 hrs
  • Excretion
    • Feces (30%)
    • Urine (23% to 40%)