Doxycycline
Also known as: Vibramycin, Doxirobe, Periostat, Doryx, Oracea, Monodox, Adoxa, Atridox, Doxybactin, Ronaxan
* **CRITICAL WARNING FOR CATS:** Do not "dry pill" your pet. Doxycycline capsules or tablets can stick in the esophagus and cause severe, permanent damage (strictures). Always follow the pill with at least 6 mL (a little more than a teaspoon) of water or liquid. Buttering the lips after administration can induce salivation and help the pill go down. * **Food and Dairy:** Doxycycline can be given with or without food. Giving it with food may help prevent stomach upset. Unlike older tetracyclines, milk or dairy products do not significantly block the absorption of doxycycline. * **Sunlight:** In rare cases, this medication can make skin more sensitive to sunlight.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Hemotropic mycoplasmosis
- Bartonellosis
- Systemic infections, bacteremia
- Ehrlichiosis or Anaplasmosis
- Clinical hemoplasmosis or bartonellosis
- Toxoplasma gondii
- Susceptible mycobacterial, L-Forms, or mycoplasma infections
- Nocardia (N. nova) infections
- Feline chlamydial infections (C. felis)
- Susceptible bacterial infections
- Feline chlamydiosis
- Lyme disease
- Equine granulocytic ehrlichiosis (anaplasmosis; EGE)
How it is given
Possible side effects
- Vomiting
- Diarrhea
- Anorexia
- Elevated liver enzymes (ALT, ALP)
- Esophageal strictures (especially in cats if dry-pilled)
- Superinfections (non-susceptible bacteria or fungi)
- Photosensitivity (reported in humans)
- Cardiac arrhythmias, collapse, and death (if given IV to horses)
- Nausea
- Diarrhoea
- Oesophagitis
- Oesophageal ulceration/stricture (especially in cats)
- Tooth discoloration (if given during tooth development, though risk is lower than other tetracyclines)
Cautions & contraindications
- Hypersensitivity to tetracyclines
- Intravenous administration in horses (associated with fatal cardiac arrhythmias)
- First half of pregnancy (can retard fetal skeletal development and discolor deciduous teeth, though less likely than other tetracyclines)
- Pregnant animals
- Animals with evidence of oesophagitis or dysphagia
- > **WARNING:** Do not administer IV to horses due to risk of fatal cardiac arrhythmias. Do not give IM or SC to any species. * **Esophageal Strictures:** Highly associated with "dry pilling" in cats. Always follow oral solid doses with at least 6 mL of water or liquid. * **Hepatotoxicity:** Use with caution in animals with significant liver dysfunction, as increases in hepatic enzymes have been documented. * **Pregnancy/Pediatric:** Use with caution in pregnant and young animals due to potential for bone and teeth abnormalities, though doxycycline is safer than older tetracyclines. * **MDR1 Mutants:** Safe to use; no dose alterations recommended for dogs with MDR1 mutations.
Drug interactions
- Oral Antacids (Aluminum, Calcium, Magnesium, Zinc, Bismuth): Chelates with divalent/trivalent cations, significantly decreasing doxycycline absorption. Give at least 1-2 hours apart.
- Bismuth Subsalicylate, Kaolin, Pectin: May reduce gastrointestinal absorption of doxycycline.
- Oral Iron: Decreases tetracycline absorption. Give iron 3 hours before or 2 hours after doxycycline.
- Penicillins / Cephalosporins / Aminoglycosides: Bacteriostatic drugs (doxycycline) may theoretically interfere with the bactericidal activity of these antibiotics.
- Phenobarbital: May decrease doxycycline half-life and reduce serum levels.
- Warfarin: Tetracyclines may depress plasma prothrombin activity; anticoagulant dosage may need adjustment.
- Antacids: Reduced absorption of doxycycline
- Calcium salts: Reduced absorption of doxycycline
- Magnesium salts: Reduced absorption of doxycycline
- Iron salts: Reduced absorption of doxycycline
Frequently asked questions
What is Doxycycline used for in pets?
* **CRITICAL WARNING FOR CATS:** Do not "dry pill" your pet. Doxycycline capsules or tablets can stick in the esophagus and cause severe, permanent damage (strictures). Always follow the pill with at least 6 mL (a little more than a teaspoon) of water or liquid. Buttering the lips after administration can induce salivation and help the pill go down. * **Food and Dairy:** Doxycycline can be given with or without food. Giving it with food may help prevent stomach upset. Unlike older tetracyclines, milk or dairy products do not significantly block the absorption of doxycycline. * **Sunlight:** In rare cases, this medication can make skin more sensitive to sunlight.
Is Doxycycline safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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