Selected Antimicrobial Information – Companion Animal

Doxycycline [Companion]

Restriction Status



Species Usage Dose
Cats For susceptible pathogens 5mg/kg q12h PO or IV or 10mg/kg q24h PO or IV (extra-label use)
Dogs For susceptible pathogens 5mg/kg q12h PO or IV or 10mg/kg q24h PO or IV (except for the treatment of heartworm disease) (extra-label use)
For heartworm disease 10mg/kg PO q12h for 28d prior to treatment with adulticide (extra-label use)

Brand Name(s)

Vibramycin®, Adoxa®, Monodox®, Oracea®, Periostat®, Doryx®, etc.


Doxycycline is a bacteriostatic, time-dependent tetracycline antibiotic with a broad spectrum of activity against many Gram-positive and Gram-negative aerobes. It is not effective against Proteus spp. or Pseudomonas spp. There is activity against some anaerobes, but efficacy against Clostridium spp. is variable. Intracellular organisms and spirochetes are often highly susceptible. Distribution is wide, and doxycycline crosses inflamed meninges. It is primarily excreted in feces.

Acceptable Uses

  • Treatment of a wide variety of local or systemic bacterial infections, including urinary tract or respiratory tract infections and bacteremia.
  • Treatment of intracellular infections, such as hemotropic Mycoplasma spp., Chlamydia spp., Ehrlichia spp., or Anaplasma spp.
  • Treatment of spirochetal infections. Preferred treatment for Lyme disease (borreliosis) or leptospirosis.
  • Pyoderma.

Unacceptable Uses

  • N/A

Formulations Available within the OSU Pharmacy

  • Doxycycline 20mg tablet
  • Doxycycline 50mg capsule
  • Doxycycline 100mg tablet
  • Doxycycline 100mg capsule
  • Doxycycline 100mg/10ml injectable suspension
  • Vibramycin 10mg/ml oral suspension
  • Vibramycin 50mg/5ml syrup


  • Doxycycline is also often used in combination with melarsomine or another adulticidal drug as part of a treatment regimen for heartworm disease.
  • Oral doxycycline is commercially available as either doxycycline hyclate or doxycycline monohydrate. Doxycycline hyclate dissociates into doxycycline and HCl, which can cause a chemical burn resulting in esophagitis in cats and small dogs. Owners should be warned to follow oral doxycycline administration with water or a small amount of food to prevent doxycycline becoming lodged in the esophagus.


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OSU VMC Antimicrobial Use Guidelines Copyright © 2018 by The Ohio State University College of Veterinary Medicine is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.