Petco Text Logo
Petco Pet Logo
  • Two Easy Ways to Start Earning Rewards!

    rewards header
    Become a member today!
    Members-only pricing and offers, personalized care notifications, Vital Care points back on every purchase and more!
    Petco Pay LogoBecome a credit card member today!

    Earn 2X Pals Rewards points at Petco
    when you use Petco Pay!

    APPLY NOW
    Learn More About Petco Pay Benefits

Azithromycin for Dogs & Cats: Bacterial, Rickettsial & Parasitic Treatment

Published on September 10, 2024
Updated on November 5, 2025
Reviewed by Petco's Veterinarian Team
Shop Related Products

Macrolide antibiotic used to treat various infections common in dogs, cats, and other pets

Summary

Used For:

A variety of bacterial, rickettsial and parasitic infections

Brands:

Zithromax

Species:

Dogs, cats, horses, small mammals, rodents, birds

Other names:

Zmax, Z-Pak

Drug type:

Antibiotic

Prescription required:

Yes

Pregnancy and lactation:

The safety of azithromycin in pregnant and lactating animals has not been determined.

Side effects:

Gastrointestinal upset

General description

Azithromycin is a macrolide antibiotic used to treat various infections common in dogs, cats, and other pets.

Uses

Susceptible bacterial infections including urinary tract infections, respiratory tract infections, oral infections, skin infections, soft tissue infections; as well as certain rickettsial and parasitic infections.

How it works

Azithromycin is a bacteriostatic antibiotic that stops bacterial growth by inhibiting protein synthesis in susceptible bacteria.

Dosage

Dogs: 5 – 10 milligrams per kilogram of body weight by mouth every 24 hours.

Cats: 5 – 10 milligrams per kilogram by mouth every 24 hours.

Horses: 10 milligrams per kilogram by mouth every 24 hours.

Rodents/Small Mammals: 15 – 50 milligrams per kilogram of body weight by mouth every 24 hours. Discontinue if soft stool occurs.

Birds: 10 – 40 milligrams per kilogram by mouth every 24 - 48 hours.

Forms

Azithromycin Oral Tablets: 250, 500, 600 milligram sizes

Azithromycin Oral Solution: 100 milligram per 5 milliliters, 200 milligrams per 5 milliliters.

Storage information & handling

Tablets: store at room temperature protected from moisture and light

Reconstituted liquid: store at room temperature and use within 10 days. Shake oral suspension well before use.

What results can I expect?

Assuming that the infection being treated is susceptible to azithromycin, resolution of the infection should occur during the treatment period.

Missed Dosage

Give the dose as soon as possible. If it is almost time for the next dose, skip the missed dose, and continue with the regular schedule. Never give two doses at once.

Overdose / acute toxicity

Overdose may cause significant vomiting and diarrhea.

Side effects

  • Vomiting
  • Diarrhea
  • Decreased appetite
  • Liver disease (rare)
  • Facial swelling/hives (rare)
  • Anaphylaxis (rare)

Contraindications

Azithromycin should not be used in animals with:

  • Macrolide sensitivity
  • Hepatic disease

Drug interactions

The following drugs may interact with azithromycin:

  • antacids
  • cisapride
  • cyclosporine
  • digoxin
  • phenytoin
  • pimozide
  • warfarin

Antacids should be administered at least 2 hours before or after azithromycin.

Precaution

Safety in pregnant or nursing animals has not been determined, use only when clearly necessary. Prolonged or repeated use of antibiotics may result in superinfection by resistant organisms

Sources

Plumb’s Veterinary Drug Handbook

VIN Veterinary Drug Handbook

Disclaimer
The information contained on this page is for educational purposes only. This medication should only be given under the advice of a veterinarian who has examined your pet under the laws applicable to your state of residence.

Have A Vet Question?

Book an appointment with the pros – our expert vets are here to help.

Share

Styled arrow button