Doxycycline: veterinary dose and monograph

At a glance

Drug class

Antibiotic

Also known as

Vibramycin, Doxirobe, Vibravenös, Doxy-100, Doxy-200

Species with doses

Dogs, Cats, Horses, Pigs, Birds, Guinea pigs, Reptiles, Chinchillas, Hamsters, Rats, Mice, Gerbils, Hedgehogs and Primates

General dose range

5–10 mg/kg PO q12–24h — check the species tables for the indication

Routes

PO, IV, IM

Last reviewed

1 October 2026

Indications

• Ehrlichiosis (E. canis, A. phagocytophilum)
• Lyme disease
• Rocky Mountain Spotted Fever
• Leptospirosis
• Mycoplasma / hemotropic mycoplasmosis
• Chlamydiosis (cats, birds)
• Bordetella infectious tracheobronchitis
• Heartworm adjunct (Wolbachia elimination)

Doxycycline dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• General susceptible infection: Plumb’s p.450 (Greene 2006): general use 3–5 mg/kg PO q12h for 7–14 days. Papich 5e: 5 mg/kg q12h PO or IV, or 10 mg/kg q24h PO. Give with food and follow tablets with water (oesophagitis).
• Soft tissue / urinary tract infection (PO or IV): Plumb's 7th Ed: 4.4–11 mg/kg PO OR IV q12h for soft tissue and urinary tract infections in dogs. Slow IV infusion only.
• Acute Ehrlichia canis: Plumb’s p.450: acute E. canis 5 mg/kg PO q12h or 10 mg/kg PO q24h for 14–16 days (Greene); 10 mg/kg q12–24h for 28 days in test-positive dogs with signs (Ford). Papich 5e: 5 mg/kg q12h for at least 14 days. Anaplasmosis 5 mg/kg q12h for 14 days (Carrade).
• Chronic E. canis: Plumb’s p.450 (Greene 2006): chronic E. canis 10 mg/kg PO q24h for 30–42 days.
• Lyme disease: Plumb’s p.450 (Appel & Jacobson 1995): 10 mg/kg PO q24h for 21–28 days.
• Leptospirosis: Plumb’s p.450 (Ford 2009): 5–10 mg/kg PO twice daily for 2 weeks, with management of the renal disease.
• Heartworm adjunct (Wolbachia): Papich 5e: 10 mg/kg q12h PO for 28 days before adulticide treatment, may be combined with ivermectin. Plumb’s p.450 (Grandi 2010): 10 mg/kg once daily for 30 days with ivermectin every 15 days.

Cats

• Hemoplasmosis / Mycoplasma: Plumb’s p.450: haemotropic mycoplasmosis 5–10 mg/kg PO once daily for 14 days (Greene); 10 mg/kg q12–24h (Lappin). Papich 5e: 10 mg/kg PO once daily for 7 days. Never dry-pill cats — follow with ≥6 mL water or use a compounded liquid (oesophageal stricture).
• Chlamydophila felis: Plumb’s p.450 (Gruffyd-Jones 2009): 10 mg/kg PO once daily for a minimum of 3–4 weeks. Follow with water (oesophageal stricture).

Horses

• Lyme disease (PO only): Plumb’s p.451 (Divers 1999): 10 mg/kg PO once to twice daily for up to 30 days. Papich 5e: horses 20 mg/kg q12h PO. NEVER give doxycycline IV to horses — fatalities reported.
• Lawsonia intracellularis (foals): Papich 5e: horses 20 mg/kg q12h PO; for Lawsonia intracellularis 20 mg/kg PO q24h for 3 weeks. NEVER give doxycycline IV to horses (fatalities).
• Anaplasmosis (EGA) — alternative to oxytetracycline: Plumb’s p.451 (Lewis et al. 2009): 10 mg/kg PO q12h for 10–14 days. Oral only in horses.

Pigs

• Miniature/pet pig — tick-borne / Lawsonia: Carpenter Exotic Animal Formulary 6th ed, Table 12-1 (p.659): miniature pigs 10–20 mg/kg PO q12h for tick-associated illness; 20 mg/kg PO q24h ×3 weeks for Lawsonia intracellularis. Pet pigs are legally food animals in many countries — obtain a withdrawal before any slaughter.

Birds

• Psittacosis (cockatiels, oral): Plumb’s p.451: cockatiels 35 mg/kg PO once daily for 21 days by crop tube (Guzman 2010); 40–50 mg/kg once daily for cockatiels, Senegals and some Amazons (Speer); 50 mg/kg q24h or divided q12h (Bauck). Papich 5e: 25 mg/kg PO q12h for 3 weeks, or 400 mg/L drinking water.
• Psittacosis — IM injectable (Vibravenös): Plumb's p.451: 75–100 mg/kg IM every 5–7 days for first 4 weeks, then every 5 days to complete a 45-day course; 75 mg/kg in macaws & lovebirds. Injectable (Vibravenös) may not be available in the USA — compounded IM products caused necrosis in one study (Flammer & Papich 2005).
• Psittacosis — African Grey / macaw / cockatoo (oral): Plumb's p.451 (Speer 1999): 25 mg/kg PO q24h for African Grey parrots, Goffin's cockatoos, Blue-and-gold & Green-winged macaws; 25–50 mg/kg PO q24h for unstudied species.

Guinea pigs

• Susceptible infection: Plumb's p.451 (Adamcak & Otten 2000): 2.5–5 mg/kg PO q12h. Do NOT use in young or pregnant animals.

Reptiles

• Susceptible infection (incl. chelonian Mycoplasma): Plumb's p.451 (Gauvin 1993): 10 mg/kg PO once daily for 10–45 days; chelonians 10 mg/kg PO q24h × 4 weeks for suspected respiratory Mycoplasma in tortoises.

Chinchillas

• Susceptible infection: Plumb's p.451 (Adamcak & Otten 2000): 2.5–5 mg/kg PO q12h. Do NOT use in young or pregnant animals.

Hamsters

• Susceptible infection: Plumb's p.451 (Adamcak & Otten 2000): 2.5–5 mg/kg PO q12h. Do NOT use in young or pregnant animals.

Rats

• Mycoplasmal pneumonia: Plumb's p.451 (Burke 1999): 5 mg/kg PO q12h combined with enrofloxacin 10 mg/kg PO q12h. General susceptible: 2.5–5 mg/kg PO q12h (Adamcak & Otten 2000).

Mice

• Mycoplasmal pneumonia: Plumb's p.451 (Burke 1999): 5 mg/kg PO q12h combined with enrofloxacin 10 mg/kg PO q12h. General susceptible: 2.5–5 mg/kg PO q12h (Adamcak & Otten 2000).

Gerbils

• Susceptible infection: Plumb's p.451 (Adamcak & Otten 2000): 2.5–5 mg/kg PO q12h. Do NOT use in young or pregnant animals.

Hedgehogs

• Susceptible infection: Carpenter Exotic Animal Formulary 6th ed, Table 8-1 (p.512): hedgehogs 2.5–10 mg/kg PO/SC/IM q12h. Compounded formulations lose potency after ~7 days — use fresh.

Primates

• Susceptible infection (prosimians, monkeys): Carpenter Exotic Animal Formulary 6th ed, Table 13-1 (p.682): prosimians 5–10 mg/kg PO q12h; chimpanzees 2–5 mg/kg PO q12h; monkeys 2.5 mg/kg PO q12h ×1 day then q24h.

Contraindications

Hypersensitivity. Last half of pregnancy only (deciduous tooth discolouration / fetal skeletal effects — less than other tetracyclines). IV route in horses is CONTRAINDICATED — cardiac arrhythmias, collapse, death reported.

Species-specific warnings

Horses: IV administration is FATAL — collapse, arrhythmias, death within minutes. ORAL route only. Even oral injection product can be mouth-irritating.

Cats: Oesophageal stricture risk — ALWAYS follow tablet with ≥6 mL water or food. Prefer oral suspension if compliance allows.

Dogs: Avoid in pregnant bitches and growing puppies (<6 mo) — bone / tooth discoloration. Mild ALT elevation common but usually self-limiting.

Birds: Psittacosis (Chlamydia psittaci) requires HIGH doses (35–50 mg/kg PO q24h × 21–45 days) — cockatiel & budgie metabolism is rapid.

Cattle: Tetracyclines accumulate in fetal/young bone — avoid in pregnant cattle and calves <6 mo. Discoloration of milk teeth can result.

Adverse effects

• GI: vomiting, diarrhoea, anorexia
• Esophageal stricture (cats) — always follow tablets with ≥6 mL water
• Elevated liver enzymes (up to 40% of dogs)
• IV in horses: fatal arrhythmias — PARENTERAL CONTRAINDICATED
• Photosensitivity (rare)

Drug interactions

• Aluminium / magnesium / calcium / iron / zinc / bismuth: chelate doxycycline — give 2 h apart from any oral mineral, milk, or antacid
• Sucralfate: chelates doxycycline — separate by 2 h
• Phenobarbital / phenytoin / carbamazepine: induce hepatic metabolism — may shorten doxycycline half-life
• Warfarin / oral anticoagulants: potentiates anticoagulant effect — monitor PT/INR
• Penicillins / beta-lactams: theoretical antagonism (bacteriostatic vs. bactericidal) — usually clinically irrelevant
• Digoxin: increased digoxin levels (gut flora suppression)
• Cyclosporine: increased cyclosporine levels

Pregnancy and lactation

AVOID in pregnant animals — tetracyclines bind developing teeth and bone, causing yellow-brown discoloration and enamel hypoplasia in offspring. Crosses placenta. Enters milk. Use alternative whenever possible. FDA Category D (human).

Monitoring

• Hepatic enzymes (ALT, ALP) — baseline and at 2–4 weeks on prolonged courses
• Cats: signs of oesophagitis (drooling, dysphagia, regurgitation) — investigate and treat promptly
• GI tolerance — discontinue or reduce if persistent vomiting
• Clinical response — Lyme / Ehrlichia titres at 3–6 months post-treatment
• Photosensitivity in lightly pigmented / outdoor animals

Toxicity and overdose

IV in horses: rapid bolus is FATAL — collapse, hypotension, cardiac arrhythmias. Cats: oesophageal stricture if tablet lodges in oesophagus — always follow with ≥6 mL water or food. Liver toxicity (elevated ALT in up to 40% of dogs, usually mild). Photosensitivity (rare). Outdated tetracyclines: nephrotoxicity from breakdown products — discard expired stock.

Management: No specific antidote. Supportive care. GI decontamination (gastric lavage, activated charcoal) if recent ingestion. IV fluids for hydration. Hepatic / renal monitoring. Anti-emetic for vomiting. Photosensitivity: avoid sun exposure. Horse IV reaction: immediate epinephrine, fluid resuscitation, oxygen.

Clinical pearls

• Cats: ALWAYS follow tablet with ≥6 mL water or a food bolus — risk of oesophageal stricture is well documented
• Horses: never give IV — ORAL route only; IV bolus is uniformly fatal
• First-line for tick-borne disease (Ehrlichia, Anaplasma, Rickettsia, Borrelia) — 5–10 mg/kg PO q12–24h × 14–28 days
• Heartworm adjunct: targets Wolbachia endosymbiont, reduces inflammation around dying worms — 10 mg/kg PO q12h × 4 weeks before melarsomine
• Doxycycline shortage workaround: minocycline at same dose is interchangeable for most indications
• Better than older tetracyclines (oxytet, tet) for intracellular pathogens due to lipophilicity

Mechanism of action

Second-generation tetracycline. Reversibly binds the 30S ribosomal subunit — prevents aminoacyl-tRNA attachment to the mRNA-ribosome complex, inhibiting bacterial protein synthesis. Bacteriostatic (becomes bactericidal at high concentrations against susceptible organisms). Lipophilic — superior tissue / intracellular penetration vs. older tetracyclines, especially CNS, prostate, eye. Also has anti-inflammatory, anti-matrix-metalloproteinase, and Wolbachia-killing activity.

Formulations and products

• 50 mg capsule/tablet
• 100 mg capsule/tablet
• Oral syrup 10 mg/mL
• Oral suspension 5 mg/mL (monohydrate powder, after reconstitution — Plumb’s p.452)
• Hyclate powder vial reconstituted to 10 mg/mL — dilute to 0.1–1 mg/mL for slow IV infusion (Papich 5e p.314; Plumb’s p.452)
• Hyclate lyophilised powder 100 mg / 200 mg vial (Doxy-100 / -200) — reconstitute per label (Plumb’s p.452)

Storage

Tablets / capsules: 15–25 °C, dry, protected from light. Compounded suspensions are unstable — refrigerate, use within 7 days, agitate well. Injectable: protect from light. Discard expired stock — breakdown products are nephrotoxic.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other antibiotics

• Clindamycin
• Cloxacillin
• Colistin (Polymyxin E)
• Danofloxacin
• Enrofloxacin
• Erythromycin
• Florfenicol
• Fusidic Acid

Frequently asked questions