Solensia Safety Update: What Cat Owners Should Review Before Each Injection
Originally published October 18, 2026. Updated October 25, 2026: clarified regulatory evidence, adverse-event uncertainty and benefit-risk review.
The FDA approved safety-labeling changes for Solensia on October 5, 2026, adding reports from use after approval and an information sheet for cat owners. Veterinarians are instructed to discuss that sheet before every injection of frunevetmab, the drug used to control osteoarthritis pain in cats.
The agency's entry describes a labeling change, not a recall announcement. For an owner deciding whether to attend the next treatment appointment, the important questions are what has changed in the cat's health and whether treatment is helping.
What owners are being asked to review
The added safety information includes reports of severe itching and skin lesions, digestive problems, difficulty walking, seizures, weakness, increased thirst or urination, and serious allergic reactions. Death, including euthanasia, was reported as an outcome in some cases involving the listed events.
Reports identify problems that need investigation; they do not establish that Solensia caused every event. The FDA says these reports cannot always establish causation or a reliable frequency. Owners should contact their veterinarian about new signs of illness rather than use a reported event count to estimate their own cat's risk.
Beyond the Headlines
Why a trial and a safety report answer different questions
Frunevetmab is a monoclonal antibody, a manufactured protein designed to bind a specific target. Its target is nerve growth factor, which is involved in pain signaling. Solensia is used to control osteoarthritis pain; pain relief should not be confused with evidence that damaged joints have been repaired.
A controlled trial compares treatment with a comparison group under defined conditions. A report after marketing records a suspected problem in an individual animal. The two can inform a treatment decision, but they cannot be substituted for one another.
A 2021 randomized, blinded study enrolled 275 cats with osteoarthritis pain: 182 received frunevetmab and 93 received placebo. Owners and veterinarians assessed response over three monthly treatments. Several measures favored frunevetmab, while skin disorders were reported more often in the treated group. Those findings concern the cats and observation period studied; they do not establish the frequency of every problem later reported in wider use.
The paper's authors disclosed employment, consultancy or other financial relationships with Zoetis. It is primary research, but it should not be presented as financially independent confirmation.
The FDA's separate explanation of the approval says the confirmatory study did not meet the success definition set in its protocol. The agency nevertheless concluded that the combined evidence supported effectiveness. Reporting only the positive findings would leave out that limitation; reporting only the missed standard would omit the regulator's overall conclusion.
Do not transfer a British frequency to the U.S. warnings
On September 1, 2026, the UK's Veterinary Medicines Directorate announced updated information on poor coordination, increased urination and increased thirst. It classified those events as very rare, using its definition of fewer than one animal per 10,000 treated, including isolated reports.
That is a description of those events in the British product information. It is not a rate for the broader U.S. list, and it does not resolve the FDA's warning about uncertain frequencies in spontaneous reports.
Make the next appointment a review of benefit and risk
Bring the injection dates, any new symptoms, changes in mobility and a list of other medicines or supplements. The FDA owner sheet calls for reassessment before each treatment. A record of what happened and when is also useful if a suspected reaction needs to be reported.
The sheet excludes cats younger than seven months or under 5.5 pounds; breeding, pregnant or nursing cats; and cats with a previous severe allergic reaction to Solensia. New health problems or a recent health change require veterinary review before starting or continuing treatment.
Seizures, severe weakness or trouble breathing need prompt veterinary attention. Do not wait for certainty about the cause before seeking help. Discuss the next injection with the prescribing veterinarian rather than making a treatment change on the basis of this article.
Owners and veterinarians can report suspected problems to the manufacturer or the FDA. The agency's reporting guidance asks for details about the animal, product, treatment and event; a useful report documents the concern without pretending to prove its cause.
Sources & further reading
- FDA — Safety-related labeling changes: October 5, 2026 Solensia entry, owner sheet and limits of spontaneous reports.
- Journal of Veterinary Internal Medicine — Gruen and colleagues, 2021: controlled frunevetmab study, methods, results and financial disclosures; DOI 10.1111/jvim.16291.
- FDA — Innovation in Animal Drug Development: FDA assessment of the combined Solensia evidence.
- Veterinary Medicines Directorate — September 1, 2026 Solensia product-information change: separate UK jurisdiction and adverse-event list.
- FDA — Reporting animal-drug side effects: reporting routes and information to include.
- FDA — Original Solensia approval summary: indication, mechanism and approval evidence.