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Defensor 1

This page contains information on Defensor 1 for veterinary use.
The information provided typically includes the following:
  • Defensor 1 Indications
  • Warnings and cautions for Defensor 1
  • Direction and dosage information for Defensor 1

Defensor 1

This treatment applies to the following species:
Company: Zoetis

Rabies Vaccine

Killed Virus

For use in dogs, cats and ferrets

PRODUCT DESCRIPTION: Defensor 1 is for vaccination of healthy dogs, cats and ferrets 12 weeks of age or older as an aid in preventing rabies. The vaccine is prepared from cell-culture-grown, chemically inactivated rabies virus. The seed virus is a highly immunogenic, fixed strain of rabies virus which originated from Louis Pasteur’s original isolate in 1882. The inactivated virus is formulated with a highly purified adjuvant and is packaged in liquid form.

DISEASE DESCRIPTION: Rabies is a worldwide, high mortality disease affecting mammalian species. Wild animals are common vectors of the disease and the major source of transmission to humans and domestic animals. Domestic animals are the major source of exposure for humans. Since 1980, the most commonly reported rabid domestic animals have been cats, cattle, and dogs. In 2011, a total of 6,031 cases of animal rabies were reported to the Center for Disease Control by 49 states and Puerto Rico.1 Susceptibility to rabies varies according to pet species. Rabies is not a treatable disease and suspect pets are usually quarantined until a clinical diagnosis is made, at which time they are destroyed.

The route of infection can be oral, respiratory, or parenteral. Following infection, a paralytic syndrome ensues, emerging as either the “furious” or “dumb” form. “Furious rabies” is characterized by unusual aggression; “dumb rabies” by lethargy and a desire to avoid contact. Respiratory failure is the immediate cause of death.

SAFETY AND EFFICACY: Because Defensor 1 is produced on an established cell line, it has safety advantages over inactivated brain-origin rabies vaccines. Tissue-origin vaccines contain extraneous protein in addition to rabies antigen that can lead to autoimmune disease.

The established cell line used in Defensor 1 has been extensively tested for freedom from contaminating agents. In addition, use of an established cell line yields a vaccine of consistent potency from serial to serial. Defensor 1 has proven to be uniformly safe in experimental tests, and no significant adverse reactions were reported in extensive clinical trials of the vaccine.

Duration of immunity studies, conducted in accordance with federal regulation and under U.S. Department of Agriculture direction, demonstrated that a 1-mL dose met federal guidelines for protection of dogs, cats and ferrets against virulent challenge administered one year after vaccination.

Directions For Use

General Directions: Shake well. Aseptically administer 1 mL subcutaneously. Dogs may be vaccinated intramuscularly or subcutaneously.

Primary Vaccination: Healthy dogs, cats and ferrets should receive a single dose at 12 weeks of age or older. A repeat dose should be administered 1 year later.

Revaccination: Annual revaccination with a single dose is recommended.


Store at 2°-8°C. Prolonged exposure to higher temperatures may adversely affect potency. Do not freeze.

Use entire contents when first opened.

Sterilized syringes and needles should be used to administer this vaccine.

Contains gentamicin and thimerosal as preservatives.

This product has not been tested in pregnant animals.

As with many vaccines, anaphylaxis may occur after use. Initial antidote of epinephrine is recommended and should be followed with appropriate supportive therapy.

Do not mix with other products.

In case of human exposure, contact a physician.

This product has been shown to be efficacious in healthy animals. A protective immune response may not be elicited if animals are incubating an infectious disease, are malnourished or parasitized, are stressed due to shipment or environmental conditions, are otherwise immunocompromised, or the vaccine is not administered in accordance with label directions.


1. Blanton JD, Dyer J, McBrayer J, Rupprecht C: Rabies surveillance in the United States during 2011. JAVMA, Vol. 241, No. 6, 2012.

Technical inquiries should be directed to Zoetis Inc. Veterinary Services, (888) 963-8471 (USA), (800) 461-0917 (Canada).

For veterinary use only

VLN 190/PCN 1905.24

Zoetis Inc., Kalamazoo, MI 49007, USA


Presentation: 50 x 1 dose and 5 x 10 dose vials.

CPN: 3690091.6

Telephone:   269-359-4414
Customer Service:   888-963-8471
Every effort has been made to ensure the accuracy of the Defensor 1 information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the US product label or package insert.

Copyright © 2020 Animalytix LLC. Updated: 2020-10-21