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Pharmaceuticals2026-05-13 · 11 min read

Librela for Dogs: OA Pain Control, Label Updates, Safety, and Fit

A label-first guide to Librela (bedinvetmab) for dogs with osteoarthritis pain, including the 2025 FDA label update, post-approval adverse events, dosing, and how it compares to NSAIDs.

Ran Chen
Ran Chen
Founder, VetMedGuide. Life-sciences operator and 10× global market-access lead.
Published

Librela (bedinvetmab injection) is the first monoclonal antibody approved in the United States to control pain associated with osteoarthritis (OA) in dogs. It works by a different mechanism than traditional nonsteroidal anti-inflammatory drugs (NSAIDs), and it has generated strong interest — and some concern — since its U.S. launch in October 2023. In February 2025, Zoetis updated the U.S. label to include post-approval adverse events reported to the FDA. This article explains what Librela is, what the label says, what the safety data show, how it compares to other OA pain options, and what to discuss with your veterinarian.

Quick answer

Librela is a once-monthly subcutaneous injection given at the veterinary clinic. It targets nerve growth factor (NGF), a protein elevated in arthritic joints that drives pain signaling. It is not an NSAID, does not go through the liver or kidneys the way oral drugs do, and is metabolized like a naturally occurring antibody.

The FDA approved Librela under NADA 141-562. In February 2025, the label was updated to include a Post-Approval Experience section and a Client Information Sheet, reflecting adverse events reported during real-world use — including neurologic signs, urinary incontinence, and in some cases death. Zoetis reports that as of December 2024, nearly 25 million doses had been distributed globally, and that no individual adverse event has been reported at a rate higher than "rare" as defined by the European Medicines Agency (fewer than 10 per 10,000 treated animals).

A 2025 comparator study published in Frontiers in Veterinary Science found that Librela provided equivalent pain relief to the NSAID meloxicam, with fewer adverse events over 56 days.

What Librela is and how it works

Bedinvetmab is a canine monoclonal antibody — a protein designed to bind specifically to nerve growth factor (NGF). NGF is elevated in the joints of dogs with osteoarthritis and contributes to pain signal transmission to the brain. When bedinvetmab binds NGF, it blocks NGF from activating its receptors (TrkA and p75NTR), reducing the pain signal.

Because monoclonal antibodies are proteins, they are broken down through normal protein degradation pathways rather than being metabolized by the liver or kidneys. This is a different pharmacokinetic profile than NSAIDs, which are processed hepatically and can affect kidney function, particularly with long-term use.

The label indication is for the control of pain associated with osteoarthritis in dogs. It is not labeled for acute pain, surgical pain, or non-OA musculoskeletal conditions.

Dosing and administration

Librela is dosed by weight range, given as a subcutaneous injection once a month.

Dog weight Vial strength
< 5 kg Withdraw 0.1 mL/kg from a 5 mg/mL vial
5–10 kg 1 vial of 5 mg/mL
10.1–20 kg 1 vial of 10 mg/mL
20.1–30 kg 1 vial of 15 mg/mL
30.1–40 kg 1 vial of 20 mg/mL
40.1–60 kg 1 vial of 30 mg/mL
> 60 kg Combination of vials per label instructions

The minimum target dose is 0.23 mg/lb (0.5 mg/kg). Each vial is single-use with no preservative — once punctured, the contents must be used immediately and any remainder discarded.

Steady-state drug levels are achieved after approximately two monthly doses. The elimination half-life is approximately 12–16 days. OA is a chronic condition, and treatment is typically ongoing for the dog's life.

What the label contraindications say

Per the prescribing information:

  • Do not use in dogs with known hypersensitivity to bedinvetmab.
  • Do not use in breeding, pregnant, or lactating dogs. Safety has not been evaluated in these populations.
  • Do not use in dogs less than 12 months of age.
  • Women who are pregnant, trying to conceive, or breastfeeding should take extreme care to avoid self-injection. Hypersensitivity reactions, including anaphylaxis, could occur with accidental self-injection.

The label also states that the safe concurrent use of Librela with long-term NSAIDs has not been established in dogs. A two-week laboratory safety study co-administering bedinvetmab with carprofen showed no adverse effect, but there are no safety data on long-term concurrent NSAID and bedinvetmab use. In human clinical trials, the combination of anti-NGF antibodies with long-term NSAIDs was associated with rapidly progressive osteoarthritis (RPOA). No equivalent of RPOA has been characterized in dogs.

Clinical trial data

Librela's approval was supported by two masked, randomized, controlled field studies:

U.S. field study (84 days): 272 dogs at 24 clinics. Dogs received Librela or sterile saline control on Days 0, 28, and 56. The percentage of dogs considered treatment successes based on owner-assessed Canine Brief Pain Inventory (CBPI) scores was greater in the Librela group at all time points.

European field study (84 days): 281 dogs. Same design. Librela-treated dogs showed greater improvement in pain interference and pain severity scores compared to controls.

The most common adverse events in the U.S. study were urinary tract infections, bacterial skin infections, and dermatitis — occurring in both the Librela and control groups.

2025 label update: Post-approval adverse events

In January 2025, the FDA sent a "Dear Veterinarian" letter alerting veterinarians to adverse events reported in dogs treated with Librela. In February 2025, Zoetis updated the U.S. label to include:

Post-Approval Experience section (2025), listing reported events in decreasing frequency:

  • Neurological: ataxia, seizures, paresis, recumbency, proprioceptive deficits
  • General: lethargy, anorexia, decreased appetite
  • Urinary: urinary incontinence, polyuria, polydipsia, inappropriate urination
  • Gastrointestinal: vomiting, diarrhea
  • Musculoskeletal: weakness, inability to rise or walk
  • Death, including euthanasia

Client Information Sheet (new): Advises owners on what Librela is, what to expect, what to discuss with their veterinarian, and how to report adverse events.

Dosage and Administration update: Veterinarians are now advised to provide the Client Information Sheet and discuss potential adverse events with the owner before every injection.

Context for the adverse event reports

The FDA adverse event database is a passive reporting system — not all events are reported, and a report does not prove the drug caused the event. The label states: "Not all adverse events are reported to FDA/CVM. It is not always possible to reliably estimate the adverse event frequency or establish a causal relationship to product exposure using these data."

Zoetis reported that nearly 25 million doses had been distributed globally as of December 2024, and that no individual adverse event sign had been reported at a rate higher than "rare" (fewer than 10 per 10,000 treated animals) per EMA criteria.

A pharmacovigilance analysis published in Frontiers in Veterinary Science (Monteiro et al., 2025) reviewed global adverse event reporting and concluded that the evidence supports continued use with appropriate monitoring. However, the analysis also identified a potential causal association for some neurological events and noted that the product labeling was updated accordingly.

The Zoetis share price declined after the FDA letter and label update, reflecting investor concern, but Zoetis maintained that the benefit-risk profile remained favorable and cited the large number of doses administered globally with a low event rate.

Librela compared to NSAIDs

A 2025 randomized, open-label study (Innes et al., published in Frontiers in Veterinary Science) compared Librela to meloxicam in 101 dogs with OA across eight UK primary care practices:

Measure Librela (n=52) Meloxicam (n=49)
Pain relief (COI score) Equivalent at Day 14; improving over 56 days Equivalent at Day 14; improving over 56 days
Dogs completing the study 44 33
Adverse events Fewer AEs reported More AEs reported

This was the first head-to-head study comparing Librela to an NSAID. Both products showed equivalent and improving efficacy. More dogs completed the study in the Librela group, and Librela was associated with fewer adverse events. However, the study was relatively small and short (56 days), and statistical significance for the difference in adverse events was not established.

Recently published expert guidelines recommend both NSAIDs and anti-NGF monoclonal antibodies as first-line therapeutic options for OA pain management in dogs.

When Librela may be preferred over an NSAID

  • Dogs with compromised kidney function (NSAIDs can reduce renal blood flow)
  • Dogs on concurrent medications that interact with NSAIDs
  • Dogs that have experienced gastrointestinal side effects from NSAIDs
  • Owners who prefer a monthly injection over daily oral medication

When an NSAID may still be appropriate

  • Dogs that have responded well to NSAIDs with good monitoring
  • Situations where oral daily dosing is preferred
  • Dogs that are not candidates for Librela (breeding animals, dogs under 12 months)

When Librela may not be the right fit

Situation Why caution is warranted
Previous adverse reaction to Librela Contraindicated per label.
Breeding, pregnant, or lactating dogs Safety not established. Contraindicated.
Dogs under 12 months of age Not labeled for use in puppies.
Dogs needing long-term concurrent NSAIDs Safety of long-term concurrent use has not been established. Short-term (2-week) co-administration was safe in a lab study.
Dogs with pre-existing neurologic conditions Pain management specialists note that Librela is best suited for dogs with "uncomplicated osteoarthritis" — dogs without concurrent neurologic disease. Dogs with intervertebral disc disease, degenerative myelopathy, or lumbosacral stenosis may not be ideal candidates because post-approval reports include neurologic events, and it can be difficult to distinguish disease progression from a drug effect.
Dogs with a history of cruciate ligament rupture in the past six months The label has not been evaluated in this population. A dog with recent cruciate injury may have pain from the ligament rather than OA, and the treatment focus should be different.
Dogs with a history of seizures or neurologic disease Post-approval reports include neurologic events (ataxia, seizures, paresis). Discuss risk with your veterinarian.
Dogs that became suddenly more active after pain relief The label warns that dogs previously unable to exercise have an increased risk of injury if activity increases rapidly after treatment. An exercise plan should be discussed.

What to discuss with your veterinarian

  • Has Librela's label been updated since my dog's last injection? The 2025 update added the Client Information Sheet and Post-Approval Experience section. Your veterinarian should review these with you before each injection.
  • What adverse events should I watch for at home? Neurologic signs (stumbling, weakness, seizures), urinary changes (incontinence, increased drinking and urinating), and sudden changes in appetite or energy should be reported.
  • Is my dog on any medication that interacts with Librela? Specifically ask about long-term NSAID use.
  • How will we know if Librela is working? Some dogs show improvement within the first week, but maximum effect typically takes two monthly injections (approximately 8 weeks) as the drug reaches steady-state levels. Improvement in mobility, willingness to walk or play, and quality-of-life changes should be tracked. The Canine Brief Pain Inventory or Liverpool Osteoarthritis in Dogs score can help monitor progress objectively.
  • What is the plan if Librela stops working? Some owners report loss of effectiveness over time. Ask about adjunctive options (weight management, physical therapy, joint supplements, Adequan) and when to re-evaluate.
  • How do I report a suspected adverse event? Report to Zoetis at 1-888-963-8471 or to the FDA at fda.gov/reportanimalae.

Key points

  • Librela is a monthly injectable monoclonal antibody that controls OA pain by targeting nerve growth factor.
  • The 2025 label update added post-approval adverse events including neurologic signs, urinary incontinence, and death. These events are rare relative to the millions of doses administered.
  • A head-to-head study found Librela equivalent in efficacy to meloxicam, with fewer adverse events over 56 days.
  • Librela is contraindicated in breeding, pregnant, and lactating dogs, and in dogs under 12 months.
  • Long-term concurrent NSAID use has not been evaluated for safety in dogs. Discuss any NSAID use with your veterinarian.
  • The updated Client Information Sheet should be reviewed before every injection.

Sources

Topics
Canine Osteoarthritis
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