Befrena for Dogs: Uses and Side Effects
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What Is Befrena Used for in Dogs?
Befrena is a veterinarian-administered, subcutaneous (under the skin) prescription injection for dogs that helps relieve itching from allergic skin conditions. It does not cure the underlying allergy—it reduces itch by blocking the itch signal.
Befrena is a monoclonal antibody (tirnovetnab) USDA-approved for dogs of any age to treat itching due to atopic dermatitis (environmental allergens like pollen, dust, and grass) and allergic dermatitis (from food, fleas, or contact irritants).
It’s given in-clinic—typically every six to eight weeks—so your veterinarian can diagnose the cause and monitor response.
Your veterinarian will determine whether Befrena is appropriate as part of your dog’s allergy treatment plan.
Key Takeaways
- Befrena is a USDA-approved monoclonal antibody injection that helps relieve itching caused by canine atopic dermatitis and allergic dermatitis in dogs of all weights and ages.
- Befrena works by binding and neutralizing a chemical messenger called interleukin-31 (IL-31) that sends itch signals to your dog’s brain. When Befrena attaches to IL-31, this blocks the allergic itch signal pathway and provides relief.
- Your veterinarian will administer the Befrena injection under your dog’s skin every six to eight weeks as needed for relief of itch due to allergies.
How Does Befrena Work in Dogs?
The active ingredient in Befrena, tirnovetnab, is a dog-specific monoclonal antibody, which is a type of protein made in the laboratory that binds to certain targets in the body—just like the antibodies in your dog’s own immune system.
Befrena helps to alleviate signs of itching such as scratching, licking, and chewing by specifically binding to and neutralizing interleukin-31 (IL-31), which is one of the main chemical messengers involved in sending itch signals to a dog’s brain.
When Befrena binds to IL-31, this interrupts the itch pathway in your dog’s body, providing relief and allowing irritated skin to heal.
How Do Vets Give Befrena to Dogs?
Your veterinarian will administer the Befrena injection under your dog’s skin, typically once every six to eight weeks based on your dog’s weight and response.
You may notice reduced itching within 24 hours, with continued improvement over the following weeks. Your veterinarian will monitor your dog’s response to determine how often future injections are needed.
What Happens If You Miss a Dose of Befrena?
If you forget to bring your dog in for their injection, please contact your vet.
In general, your veterinarian will schedule an appointment for your dog as needed to assess your dog’s response to Befrena and administer the next treatment.
What Are the Side Effects of Befrena in Dogs?
Befrena is typically well-tolerated in most dogs.
Uncommon side effects that can occur within the first few days after the injection include:
- Low energy (lethargy)
- Diarrhea
- Vomiting
- Tenderness or swelling at the injection site (which usually resolves within 24 hours)
- Bacterial skin infection
Human Side Effects
Befrena is not an approved medication for humans. To be safe, do not participate in any way during the injection. Veterinary staff will hold your dog as the vet administers the medication.
If you accidentally become injected with a pet medication, seek medical attention immediately in person. Show the package leaflet or label, if available, to the physician, and call Poison Control at 1-800-222-1222.
Monitoring Your Pet
No specific monitoring is required for this medication, but your veterinarian may recommend routine testing depending on your dog’s individual needs, other medications that may be prescribed, and/or the issue that initially caused your dog to be placed on this medication.
When Should You Call Your Veterinarian?
Call your veterinarian if you see any of the following, or if you have additional questions or concerns about the use of Befrena:
- Severe side effects
- Your pet’s condition worsens or does not improve
- You suspect an overdose
What Happens If a Dog Overdoses on Befrena?
If you suspect an overdose, seek emergency veterinary care or contact an animal poison control center. Consultation fees may apply.
- Pet Poison Helpline: 855-764-7661
- ASPCA Animal Poison Control: 888-426-4435
Befrena for Dogs FAQs
How long does Befrena take to work in dogs?
Befrena starts working to control itching within 24 hours.
Can Befrena be used with other medications?
Yes, Befrena can be used safely in dogs who take other medications. In a field safety study, it was shown to be safe alongside a wide variety of treatments. Be sure to tell your veterinarian about all medications, vitamins, and supplements your dog is taking.
Is Befrena safe for all dogs?
Yes, Befrena is considered safe for dogs of any age and weight when used under the guidance of a veterinarian. They will consider your dog’s medical history and overall health to determine whether it’s the right option.
No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content is sourced from public references or the manufacturer.
