Tylosin
Tylosin tartrate / Tylosin phosphate
Also known as: Tylan Soluble · Bilosin · Tyluvet · Desmycosin · tilosina · tylozin · tylosiini · tylosinum · tylozyna
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidenceSusceptible enteric infections (extra-label)
- q12-24h
NA
Governing clinical context (2)
- ■ Oral doses may be given with or without food. Give this medicine with food if stomach upset or vomiting occurs.
- ■ The powder has an extremely bitter taste. The animal may be more likely to accept the medication if the powder is placed in an empty gelatin capsule.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Tylosin is a macrolide antibiotic naturally produced by Streptomyces fradiae. While primarily FDA-approved for use in livestock (cattle and swine) to treat respiratory and enteric infections, it is a staple in small animal medicine for managing Tylosin-Responsive Diarrhea (TRD), chronic colitis, and inflammatory bowel disease (IBD).
Key Clinical Pearls:
- Microbiome Modulation: In dogs, tylosin is uniquely effective for TRD. This is likely due to its ability to modulate the intestinal microbiome (specifically promoting beneficial Enterococcus spp.) and its immunomodulatory effects, rather than purely through its direct antimicrobial properties.
- Epiphora Management: It has been used anecdotally to reduce tear staining (epiphora) in dogs (e.g., Maltese, Poodles) by binding porphyrins or altering normal flora, though this use is controversial due to antimicrobial stewardship concerns.
- FIP: Anecdotally used in cats as an immunomodulating agent for Feline Infectious Peritonitis (FIP), though evidence is limited.
Mechanism of action
Tylosin shares a mechanism of action with erythromycin:
- Antimicrobial Action: Binds reversibly to the 50S ribosomal subunit of susceptible bacteria → inhibits translocation of peptides → prevents protein synthesis. It is primarily bacteriostatic, but can be bactericidal at high concentrations.
- Spectrum of Activity: Effective against Gram-positive bacteria, Mycoplasma, Chlamydia, and some Gram-negative anaerobes (e.g., Clostridium perfringens).
- Immunomodulation & Probiotic Effect: Alters cell-mediated immunity. In dogs, it specifically increases jejunal concentrations of Enterococcus faecalis, which acts as a probiotic to stabilize the gut barrier and resolve chronic diarrhea.
Safety & warnings
Contraindications
- Hypersensitivity to tylosin or other macrolide antibiotics
- Horses (causes severe and potentially fatal dysbiosis/diarrhea)
- No specific contraindications available in the monograph
Adverse effects
- Pain and local reactions at IM injection sites
- Mild GI upset (anorexia, diarrhea) in small animals
- Severe/fatal diarrhea in horses (any route)
- Severe diarrhea in ruminants (PO)
- Swine: edema of rectal mucosa, mild anal protrusion with pruritus, erythema, and diarrhea
- Gastrointestinal disturbances
- Pain at the site of injection
Precautions
Use cautiously in pregnant animals (Class B). Strictly avoid oral administration in ruminants and any route in horses due to the risk of fatal dysbiosis. Macrolides may cause falsely elevated AST (SGOT) and ALT (SGPT) values when using colorimetric assays, and can alter fluorometric determinations of urinary catecholamines.
Drug interactions
May increase digoxin blood levels, potentially resulting in toxicity
Monitoring
- Clinical efficacy (resolution of diarrhea or infection)
- Adverse effects (GI upset, injection site reactions)
- Clinical response (resolution of diarrhea or infection)
- Injection site for pain or inflammation
Pharmacokinetics
Half-life
Absorption
Well absorbed from the GI tract (tartrate salt is better absorbed than phosphate salt). Rapidly absorbed after SC or IM injection.
Distribution
Widely distributed in the body, with the exception of penetration into the CSF. Volume of distribution: 1.7 L/kg (small animals), 1-2.3 L/kg (cattle). Milk to plasma ratio in lactating dairy cattle is 1-5.4.
Metabolism
Minimal hepatic metabolism.
Elimination
Eliminated in the urine and bile primarily as unchanged drug.
Overdose
Tylosin is relatively safe in most overdose situations.
- Dogs: Tolerate oral doses up to 800 mg/kg. Long-term (2-year) oral administration of up to 400 mg/kg produced no organ toxicity.
- Pigs: LD50 is >5 g/kg PO, and ~1 g/kg IM. However, shock and death have been reported in baby pigs overdosed with tylosin.
Available products
Formulations
- Injectable solution: 50 mg/mL, 200 mg/mL
- Soluble powder (tartrate salt): ~2.5-2.7 g/tsp
- Injectable solution: 200 mg/ml
- Oral soluble powder: 100 g/bottle
Veterinary
- Tylosin Injection: 50 mg/mL, 200 mg/mL (Tylan®)
- Tylosin Tartrate Powder: ~2.5-2.7 grams/level tsp in 100g bottles (Tylan® Soluble)
- Bilosin 200 mg/ml injectable solution
- Tylan 200 mg/ml injectable solution
- Tyluvet 200 mg/ml injectable solution
- Tylan 100 g/bottle soluble powder
Regulatory status
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store injectable tylosin in well-closed containers at room temperature. Tylosin is unstable in acidic media (pH < 4). Do not mix the parenteral injection with other drugs.
Client information
Important: Tylosin powder is notoriously bitter and foul-tasting. Most pets will refuse to eat it if it is simply sprinkled on top of their food.
Tips for Administration:
- Capsules: The easiest way to give the powder is to have your veterinarian or a compounding pharmacy place the exact dose into empty gelatin capsules.
- The Butter Trick: If capsules aren't an option, melt about ¼ teaspoon of butter, mix the proper dose of tylosin powder into it, place it in a mini ice-cube tray, and freeze it into a "pill" that can be hidden in a treat.
General Guidance:
- Follow your veterinarian's dosage recommendations carefully.
- If treating chronic diarrhea, do not stop the medication abruptly even if your pet's stool returns to normal, as the diarrhea often returns quickly without the medication.
- Tylosin is generally very well tolerated, but contact your veterinarian if you notice any adverse effects like vomiting or loss of appetite.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.