Tylosin

Tylosin is a macrolide antibacterial used for selected susceptible infections in livestock and poultry. It also has an extra-label role in some dogs with recurrent tylosin-responsive diarrhea. Tartrate, phosphate and other preparations have different delivery applications. The evidence for an enteric clinical response is distinct from proof of a specific bacterial cause.

Group

Macrolide antibacterial

Mechanism of Action

Tylosin binds the bacterial 50S ribosomal subunit and inhibits peptide-chain elongation, usually suppressing bacterial growth. Activity favors susceptible gram-positive organisms, mycoplasmas and selected livestock pathogens. In tylosin-responsive canine diarrhea, changes in intestinal bacterial populations may contribute to improvement, but the full mechanism and the role of non-antibacterial effects remain uncertain.

Dose Rates

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	7–15 mg/kg	PO	Every 12–24 h
Susceptible infection	8–11 mg/kg	IM	Every 12 h
Colitis — Initial	12–20 mg/kg	PO	Every 8 h	Give with food; lengthen interval stepwise only after response.
Colitis — Maintenance	12–20 mg/kg	PO	Every 12 h	Give with food; lengthen interval stepwise only after response.
Colitis — Maintenance	12–20 mg/kg	PO	Every 24 h	Give with food; lengthen interval stepwise only after response.
Inflammatory bowel disease adjunct	10 mg/kg	PO	Every 8 h	Up to 21 days
Clostridial colitis	10–40 mg/kg	PO	Every 12 h
Inflammatory bowel disease or antibiotic-responsive diarrhea	20–40 mg/kg	PO	Every 12 h
Small intestinal bacterial overgrowth	10–20 mg/kg	PO	Every 12 h	Up to 42 days
Tylosin-responsive diarrhea	25 mg/kg	PO	Every 24 h	Up to 7 days; Study course 7 days; relapse may follow withdrawal.

Cats

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	7–15 mg/kg	PO	Every 12–24 h
Susceptible infection	8–11 mg/kg	IM	Every 12 h
Inflammatory bowel disease adjunct	10 mg/kg	PO	Every 8 h	Up to 21 days
Clostridial colitis	10–40 mg/kg	PO	Every 12 h
Inflammatory bowel disease or antibiotic-responsive diarrhea	20–40 mg/kg	PO	Every 12 h
Inflammatory bowel disease	40 mg/kg	PO	Every 12 h

Pigs

Use / stage	Dose	Route	Schedule	Instructions
Arthritis, erysipelas or dysentery	8.8 mg/kg	IM	Every 12 h
Bacterial infection with tylosin base	12.5 mg/kg	IM	Every 12 h

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Pododermatitis or pneumonia	17.6 mg/kg	IM	Every 24 h
Refractory bacterial pneumonia	44 mg/kg	IM	Every 24 h	200 mg/mL product, specific resistant-infection report; historical foreign withdrawal is not local authorization.
Bacterial infection with tylosin base — Loading	10 mg/kg	IM	Once
Bacterial infection with tylosin base — Maintenance	6 mg/kg	IM	Every 8 h	Calf interval alternative every 8-12 hours.

Ferrets

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	10 mg/kg	PO	Every 12–24 h

Rabbits

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	10 mg/kg	SC, IM	Every 12–24 h	Historical rabbit use conflicts with guidance contraindicating oral administration; route remains unresolved.

Gerbils

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

Hamsters

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

Rats

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

Birds

Use / stage	Dose	Route	Schedule	Instructions
Upper respiratory infection	40 mg/kg	IM		200 mg/mL preparation; often a combination protocol.
Upper respiratory infection or airsacculitis	10–40 mg/kg	IM	Every 8–12 h
Susceptible infection	30 mg/kg	IM	Every 12 h

Reptiles

Use / stage	Dose	Route	Schedule	Instructions
Susceptible infection	5 mg/kg	IM	Every 24 h	Tortoise chronic respiratory courses are reported for at least 10 days.

Indications

Treatment of selected susceptible bovine respiratory infections or foot rot with a corresponding product.
Treatment of selected susceptible swine mycoplasmal disease, pneumonia, erysipelas or proliferative enteropathy where covered by the product indication.
Treatment of selected susceptible poultry respiratory infections with an indicated product.
Treatment of selected recurrent tylosin-responsive diarrhea in dogs after appropriate investigation, with evidence of response in a defined subset of patients.
Treatment of selected susceptible gram-positive infections in other veterinary patients, with organism- and species-specific support.

Contraindications

Horses
Do not administer orally to rabbits or rodents.
Avoid IV injection.

Adverse effects

Diarrhea and porcine skin reactions; equine administration can be fatal.

Toxicity

Marked overdose has caused shock and death in piglets. Species and route sensitivity remain important even when oral canine tolerance is relatively high.

Preparations

Preparation	Form	Strength	Route
Tylosin injection 50 mg/mL	Injection	50 mg / mL	IM
Tylosin injection 200 mg/mL	Injection	200 mg / mL	IM

Monitoring and Administration

Assess response and use appropriate injection site volume, not more than 10 mL/site. Colitis protocols can taper frequency after response.

Distinguish tartrate, phosphate and base strengths; reported guidance states tartrate is 80% tylosin base.

Product-specific treatment maxima are 5 days for cattle and 3 days for pigs; maximum injection-site volumes are 10 mL cattle and 5 mL pigs. Approximate powder teaspoon masses vary between 2.5-2.7 g and are not a verified density conversion. Historical slow IV cattle use conflicts with guidance to avoid IV administration; the route remains disputed.