Veterinary & Aquatic Services Department, Drs. Foster & Smith

Generic Name

Brand Name
Multiple human brands

Type of Drug

Form and Storage
Tablet, capsule, oral suspension, and injectable
Store at room temperature in a tightly closed container protected from light. Refrigerate the oral suspension.

Indications for Use
Treatment of susceptible bacterial infections.

General Information
Only the injectable form is FDA approved for use in dogs and cats; although, it is a common and accepted practice to use the other forms also. Available by prescription. Several chemically different forms of erythromycin are available. Usually bacteriostatic, but at high doses, may be bacteriocidal.

Usual Dose and Administration
Dogs and Cats: 2.25-9 mg/pound by mouth (tablet, capsule, oral suspension) every 8 hours. Duration of treatment depends on reason for treatment and response to treatment.

Side Effects
May see lack of appetite, vomiting, or diarrhea.

Not for use in patients hypersensitive (allergic) to it.

Do not use in pregnant or nursing animals.

Use with caution in animals with liver disease.

Drug or Food Interactions
Do not use in combination with clindamycin, lincomycin, chloramphenicol, or penicillin.

May cause theophylline or digoxin levels to rise to toxic levels, and may increase the levels of terfenadine possibly causing severe heart problems.

May increase bleeding time if used with warfarin.

May decrease the metabolism of methylprednisolone (a steroid).

Phenytoin may increase the levels of erythromycin.

Food decreases the absorption of erythromycin, but small meals may need to be given with the medication to decrease side effects.

Unlikely. May see lack of appetite, vomiting, or diarrhea.


Erythromycin is an antibiotic used to treat certain types of diarrhea, skin infections and prostate infections. Contact your veterinarian if your pet experiences diarrhea, vomiting, or decreased appetite while being treated with erythromycin.

   Click here for the web viewable version of this article.

Click here to email this article to a friend.

Keep this and all other medications out of the reach of children and pets.

If you think your pet has been poisoned...

Contact your veterinarian or one of the Animal Poison Hotlines (listed below) if you think your pet may have accidentally received or been given an overdose of the medication.

**ASPCA Animal Poison Control Center - 24-hour service available throughout North America.

1-888-4ANI-HELP (1-888-426-4435). $65.00 per case, billed to caller's credit card.

Follow-up calls can be made for no additional charge by dialing 888-299-2973.

There is no charge when the call involves a product covered by the Animal Product Safety Service.

**Pet Poison Helpline - 24-hour service available throughout North America for pet owners and veterinary professionals who require assistance with treating a potentially poisoned pet.

1-800-213-6680 ($59.00 per incident). Staffed 24-hours a day.

Updated 6/20/17

Copyright © 1997-2017, Foster & Smith, Inc. All Rights Reserved.
Reprinted from