Oxytetracycline

Oxytetracycline is a tetracycline antibacterial used widely in livestock and for selected equine infections. Its spectrum includes susceptible conventional and intracellular organisms, with applications such as bovine respiratory disease, anaplasmosis and Potomac horse fever. A separate non-antibacterial application is treatment of selected neonatal foal flexural limb deformities.

Group

Tetracycline antibacterial

Mechanism of Action

Oxytetracycline reversibly binds the bacterial 30S ribosomal subunit and blocks aminoacyl-transfer RNA access, inhibiting protein synthesis and usually producing bacteriostatic activity. In foals, proposed effects on matrix-metalloproteinase expression, myofibroblast activity and collagen organization can reduce tendon-associated contracture. That non-antibacterial mechanism is incompletely defined and is distinct from its ribosomal target.

Dose Rates

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Bacterial infection	7.5–10 mg/kg	IV	Every 12 h
Bacterial infection	20 mg/kg	PO	Every 12 h
Bacterial infection	22 mg/kg	PO	Every 8 h	Up to 14 days
Bacterial infection	20 mg/kg	PO	Every 8–12 h
Depot antibacterial treatment	20 mg/kg	IM	Every 168 h	Repositol formulation specifically; do not apply to conventional injection.
Salmon poisoning adjunct	7 mg/kg	IV	Every 8 h	Up to 5 days; Reported course 3-5 days.
Antibiotic-responsive diarrhea	10–20 mg/kg	PO	Every 8 h

Cats

Use / stage	Dose	Route	Schedule	Instructions
Bacterial infection	7.5–10 mg/kg	IV	Every 12 h
Bacterial infection	20 mg/kg	PO	Every 12 h
Hemotropic mycoplasmosis	10–25 mg/kg	PO, IV	Every 8 h	Up to 7 days; Reported 5-7 days; persistent infection can remain.
Bacterial infection	20 mg/kg	PO	Every 8–12 h
Inflammatory bowel disease antibiotic trial	10–20 mg/kg	PO	Every 8 h

Horses

Use / stage	Dose	Route	Schedule	Instructions
Rickettsial and other susceptible infection	10 mg/kg	IV, IM	Every 24 h	Slow IV administration; IM use may cause pain and local reactions.
Piroplasmosis	5–6 mg/kg	IV	Every 24 h	Up to 7 days
Flexural limb deformity	44 mg/kg	IV	Every 24 h	Up to 2 days; Foals only; give slowly. Two doses 24 hours apart. Reported regimen describes escalation up to 70 mg/kg and approximately 2-3 g/foal.
Flexural limb deformity	70 mg/kg	IV	Every 24 h	Up to 2 days; Higher reported foal regimen; give slowly and reassess before the second dose.
Foal bacterial infection	5–10 mg/kg	IV	Every 12 h	Foals; dilute and administer slowly.
Foal bacterial infection	10–20 mg/kg	IV	Every 24 h	Foals; dilute and administer slowly.
Rickettsial infection	6.6 mg/kg	IV	Every 24 h	Dilute at least 1:1; administer slowly or in 500-1000 mL fluid.
Lyme disease	5–6.6 mg/kg	IV	Every 12 h	Up to 28 days; Reported 3-4 week course.
Potomac horse fever	6.6 mg/kg	IV	Every 12 h	Up to 5 days; Usually no more than 5 days.
Proliferative enteropathy in foals	5–6.6 mg/kg	IV	Every 12 h	Up to 7 days; Initial 3-7 days then doxycycline 10 mg/kg PO every 12 hours for 7-17 days.
Proliferative enteropathy combination	10–18 mg/kg	IV	Every 24 h	Slow IV with metronidazole 10-15 mg/kg PO every 8-12 hours.

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Enteric bacterial infection in calves	11 mg/kg	PO	Every 24 h
Pneumonia in calves	11 mg/kg	PO	Every 12 h
Systemic bacterial infection	11 mg/kg	IV	Every 12 h
Long-acting antibacterial treatment	20 mg/kg	IM	Once	Long-acting formulation only.
Long-acting product antibacterial treatment	20–30 mg/kg	IM	Every 72–120 h	Do not use in: Established renal insufficiency; Oxy-LA 200 mg/mL product: repeat after 3-5 days if necessary; deep IM. Meat withdrawal 30 days, milk 14 days.
Long-acting antibacterial treatment	20 mg/kg	SC	Once	LA-200 formulation.
Bacterial infection with conventional schedule	6.6–11 mg/kg	IM, SC, IV	Every 24 h	Up to 4 days; Product-specific label alternative; slow IV over at least 5 minutes when specified; reassess within 24-48 hours.
Respiratory disease control	30 mg/kg	IM, SC	Once	300 mg/mL Tetradure formulation.
Pneumonia or infectious keratoconjunctivitis	20–30 mg/kg	IM, SC	Once	300 mg/mL product-specific alternative.
Respiratory bacterial infection	11 mg/kg	IM, SC	Every 24 h	50 mg/mL conventional injection.
Respiratory bacterial infection	11 mg/kg	IV	Every 12–24 h	50 mg/mL conventional injection.
Respiratory bacterial infection	20 mg/kg	IM	Every 24 h	100 mg/mL product.
Respiratory bacterial infection	20 mg/kg	IM	Every 72–96 h	200 mg/mL long-acting product.
Anthrax	4.4 mg/kg	IM, IV	Every 24 h	May negate a recent live anthrax vaccination in healthy animals.
Anaplasmosis carrier treatment	22 mg/kg	IM, IV	Every 24 h	Up to 5 days; Conventional 50/100 mg/mL product; IV diluted in saline, IM no more than 10 mL/site.
Anaplasmosis carrier treatment	11 mg/kg	IM, IV	Every 24 h	Up to 10 days; Conventional 50/100 mg/mL product; IV diluted in saline, IM no more than 10 mL/site.
Anaplasmosis carrier treatment	20 mg/kg	IM	Every 72 h	Depot formulation, four treatments in divided deep-IM sites.
Anaplasmosis herd protection	6.6–11 mg/kg	IM	Every 504–672 h	Conventional formulation during vector season, extending 1-2 months afterwards.
Anaplasmosis herd protection	20 mg/kg	IM	Every 672 h	Depot formulation alternative.
Pneumonia	11 mg/kg	SC	Every 24 h
Pneumonia	20 mg/kg	IM	Every 48 h	Depot formulation.

Pigs

Use / stage	Dose	Route	Schedule	Instructions
Bacterial infection	6.6–11 mg/kg	IM	Every 24 h
Bacterial infection	10–20 mg/kg	IM	Every 24 h
Bacterial infection	20 mg/kg	IM	Every 48 h
Long-acting product antibacterial treatment	20 mg/kg	IM	Every 72–120 h	Oxy-LA product; a second dose may be required after 3-5 days.
Anthrax	4.4 mg/kg	IM, IV	Every 24 h	May negate a recent live anthrax vaccination in healthy animals.
Sow periparturient enteritis control	6.6 mg/kg	IM	Once	300 mg/mL product: about 8 hours before farrowing or immediately after completion.
Bacterial infection	10–20 mg/kg	PO	Every 6 h
Conventional injection antibacterial treatment — Initial	10 mg/kg	IM	Once
Conventional injection antibacterial treatment — Maintenance	7.5 mg/kg	IM	Every 24 h

Buffalo

Use / stage	Dose	Route	Schedule	Instructions
Long-acting product antibacterial treatment	20–30 mg/kg	IM	Every 72–120 h	Do not use in: Established renal insufficiency; Oxy-LA 200 mg/mL product: repeat after 3-5 days if necessary; deep IM. Meat withdrawal 30 days, milk 14 days.

Camel

Use / stage	Dose	Route	Schedule	Instructions
Long-acting product antibacterial treatment	20–30 mg/kg	IM	Every 72–120 h	Do not use in: Established renal insufficiency; Oxy-LA 200 mg/mL product: repeat after 3-5 days if necessary; deep IM. Meat withdrawal 30 days, milk 14 days.

Sheep

Use / stage	Dose	Route	Schedule	Instructions
Long-acting product antibacterial treatment	20–30 mg/kg	IM	Every 72–120 h	Do not use in: Established renal insufficiency; Oxy-LA 200 mg/mL product: repeat after 3-5 days if necessary; deep IM. Meat withdrawal 30 days, milk 14 days.
Anthrax	4.4 mg/kg	IM, IV	Every 24 h	May negate a recent live anthrax vaccination in healthy animals.
Enteritis or pneumonia	22 mg/kg	PO	Every 24 h	Up to 14 days; In drinking water for 7-14 days.

Goat

Use / stage	Dose	Route	Schedule	Instructions
Long-acting product antibacterial treatment	20–30 mg/kg	IM	Every 72–120 h	Do not use in: Established renal insufficiency; Oxy-LA 200 mg/mL product: repeat after 3-5 days if necessary; deep IM. Meat withdrawal 30 days, milk 14 days.
Anthrax	4.4 mg/kg	IM, IV	Every 24 h	May negate a recent live anthrax vaccination in healthy animals.
Enteritis or pneumonia	22 mg/kg	PO	Every 24 h	Up to 14 days; In drinking water for 7-14 days.

Poultry

Use / stage	Dose	Route	Schedule	Instructions
Long-acting product antibacterial treatment	30–60 mg/kg	IM	Every 72–120 h	Oxy-LA product instruction derived from 0.15-0.30 mL/kg at 200 mg/mL; no egg withdrawal supplied.

Rabbits

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	15 mg/kg	SC, IM	Every 8 h
Susceptible infection	15–50 mg/kg	PO	Every 24 h
Reported E. cuniculi adjunct	20 mg/kg	SC	Every 24 h	Historical reported use; efficacy is not established by this dose listing.

Chinchillas

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	50 mg/kg	PO	Every 12 h

Gerbils

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	10 mg/kg	PO	Every 8 h
Susceptible infection	20 mg/kg	SC	Every 24 h

Guinea pigs

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	50 mg/kg	PO	Every 12 h

Hamsters

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	16 mg/kg	SC	Every 24 h

Mice

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	10–20 mg/kg	PO	Every 8 h

Rats

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	10–20 mg/kg	PO	Every 8 h
Susceptible infection	6–10 mg/kg	IM	Every 12 h

Birds

Use / stage	Dose	Route	Schedule	Instructions
Chlamydiosis	50 mg/kg	IM	Every 72–120 h	200 mg/mL depot product; severe local tissue reactions possible.
Chlamydiosis outbreak control	200 mg/kg	IM	Every 24 h	Up to 5 days; Separate historical 3-5 day report with oral tetracycline transition; high exposure and local injury risk require species-specific assessment.

Reptiles

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	10 mg/kg	PO	Every 24 h	Up to 7 days; Turtles and tortoises; reported ulcerative stomatitis use.

Indications

Treatment of susceptible livestock respiratory, wound, soft-tissue or selected enteric infections with a corresponding veterinary product.
Treatment of bovine anaplasmosis caused by susceptible Anaplasma marginale.
Treatment of selected infectious bovine keratoconjunctivitis caused by susceptible organisms.
Treatment of Potomac horse fever and selected other equine intracellular bacterial infections, including supported anaplasmosis or proliferative enteropathy regimens.
Treatment of selected avian chlamydial infections with a species-appropriate regimen.
Specialist treatment of selected flexural limb deformities in neonatal foals.

Contraindications

Prolonged treatment in growing animals may discolor teeth.
Large IM volumes cause local injury.

Interactions

Chelates calcium, iron, aluminum and magnesium; these can reduce absorption or cause incompatibility.

Adverse effects

Injection pain, diarrhea or colic in horses, feline drug fever; excessive doses can cause renal or hepatic injury and metabolic abnormalities.

Toxicity

Excess exposure can cause gastrointestinal disease, renal accumulation and rumen stasis. Rapid IV tetracycline or propylene-glycol vehicle can provoke collapse, arrhythmias or hemolysis; dilution and slow administration are important.

Preparations

Preparation	Form	Strength	Route
Oxytetracycline injection 100 mg/mL	Injection	100 mg / mL	IV, IM
Oxytetracycline injection 200 mg/mL	Injection	200 mg / mL	IV, IM
Oxytetracycline 250 mg	Tablet	250 mg / tablet	PO
Oxytetracycline 500 mg	Tablet	500 mg / tablet	PO
Oxy-LA injection 200 mg/mL Selmore Pharmaceuticals Oxytetracycline equivalent as HCl; long-acting deep IM product. Shake before use; do not use with established renal insufficiency. Product withdrawal: meat 30 days, milk 14 days.	Injection	200 mg / mL	IM
Oxytetracycline conventional injection 50 mg/mL	Injection	50 mg / mL	IV, IM, SC
Oxytetracycline 300 mg/mL long-acting injection Tetradure-type source presentation; IV use only when the exact product instructions authorize it.	Injection	300 mg / mL	IM, SC
Terramycin oxytetracycline/polymyxin B ophthalmic ointment Sterile ocular ointment contains oxytetracycline HCl 5 mg and polymyxin B sulfate activity 10000 IU per gram; no single-component calculator opt-in.	Other	oxytetracycline hydrochloride 5 mg / g + polymyxin b 10000 IU / g	TOPICAL

Monitoring and Administration

Conventional and long-acting injections require different schedules; long-acting behavior does not apply to IV administration. Limit IM volume to 10 mL/site in cattle and 5 mL/site in pigs.

Inject IV slowly and monitor hydration, renal function and gastrointestinal signs. Use diluted injection immediately; protect stock from light.

Unnormalized local protocols include equine intrauterine 1-5 g using povidone-based products only. Canine tear-staining reports use 25-50 mg/day with two-week on/off cycles; antimicrobial stewardship and uncertain benefit limit this indication. Pregnant-ewes campylobacteriosis and some bovine anaplasmosis/listeriosis lines lack an explicit route; they are not assigned one.