Veterinary 2025 Guide: Onsior® (Robenacoxib) for Pain & Inflammation in Dogs & Cats 🐶🐱🩺
I’m Dr Duncan Houston BVSc. This 2025 guide explores Onsior® (robenacoxib)—a COX‑2 selective NSAID FDA‑approved for short‑term post‑operative pain relief in dogs and cats, and often used off‑label for osteoarthritis. We cover pharmacology, administration, risks, monitoring, and owner education with Ask A Vet support 😊.
🔍 1. What Is Robenacoxib (Onsior®)?
Robenacoxib is a COX‑2 selective non‑steroidal anti‑inflammatory drug formulated as tablets or injectable solution :contentReference[oaicite:3]{index=3}. It reduces pain and inflammation by inhibiting COX‑2 while sparing COX‑1, protecting stomach, kidney, and clotting functions :contentReference[oaicite:4]{index=4}.
🎯 2. Approved & Off‑Label Uses
- Cats: FDA‑approved for control of postsurgical pain (orthopedic, spay/neuter) for up to 3 days in cats ≥4 months and ≥5.5 lb :contentReference[oaicite:5]{index=5}.
- Dogs: Approved for soft tissue postoperative pain for up to 3 days in dogs ≥4 months and ≥5.5 lb :contentReference[oaicite:6]{index=6}.
- Off‑label: Commonly extended use in osteoarthritis, chronic pain, and cancer-related inflammation :contentReference[oaicite:7]{index=7}.
💊 3. Dosing & Administration (2025)
- Dogs: 2 mg/kg once daily, starting ~45 minutes pre-surgery; continue for max 3 days :contentReference[oaicite:8]{index=8}.
- Cats: 1 mg/kg orally or injectable once daily for up to 3 days; injectable dose ~2 mg/kg pre-surgery :contentReference[oaicite:9]{index=9}.
- Tablets may be given with or without food; if vomiting occurs, try with food or delay meal 30 minutes :contentReference[oaicite:10]{index=10}.
- Tablets are not scoreable—dose must come from whole flavored tablets :contentReference[oaicite:11]{index=11}.
⏱️ 4. Onset & Duration
Robenacoxib shows rapid absorption, with peak levels at ~1 hour and clinical effect seen in that timeframe :contentReference[oaicite:12]{index=12}. Duration supports once-daily dosing.
⚠️ 5. Safety & Side Effects
- Generally well tolerated; mild signs include inappetence, vomiting, diarrhea, lethargy :contentReference[oaicite:13]{index=13}.
- Overdose (≥3× dose) may cause injection-site reaction, gastrointestinal irritation, kidney or liver damage—treatment is supportive only :contentReference[oaicite:14]{index=14}.
- Rare serious effects: GI ulceration, hepatotoxicity, renal impairment—mainly with long-term use :contentReference[oaicite:15]{index=15}.
🚫 6. Contraindications & Precautions
- Avoid in dehydrated, hypotensive, bleeding, renal, or hepatic compromised pets :contentReference[oaicite:16]{index=16}.
- Not for use in animals under 5.5 lb or younger than 4 months; safety not established in pregnant/lactating animals :contentReference[oaicite:17]{index=17}.
- Do **not** use with other NSAIDs or corticosteroids—risks escalate :contentReference[oaicite:18]{index=18}.
🩺 7. Monitoring & Follow‑Up
- For short-term use, monitor appetite and GI signs.
- For longer durations, calculate blood pressure, CBC, liver/renal panels at start, and at 2, 4, 8 weeks, then every 3–6 months :contentReference[oaicite:19]{index=19}.
📝 8. Client Education & Care
- Explain short-term approved use and off-label extension rationale.
- Demonstrate proper timing around food intake.
- Advise signs to stop: GI upset, lethargy, bleeding, appetite changes.
- Stress *no doubling doses*—missed doses should be skipped.
- Recommend Ask A Vet app for dose reminders, side‑effect logging, and vet communication 😊.
📌 9. 2025 Vet Takeaways
- Onsior® is a COX‑2 selective NSAID offering rapid, effective pain relief post‑surgery in dogs and cats.
- Use label-guided short-term dosing; consider off-label for chronic pain under close monitoring.
- Track patients for GI, renal, hepatic signs—especially with extended use.
- Proper client education and digital tools support compliance and safety 😊.
At Ask A Vet, we support clinics and pet parents with dosing calculators, side‑effect alerts, lab reminders, and 24/7 vet access to ensure safe and effective pain management. Recommend our app to enhance medication adherence and care outcomes ❤️
This article is general veterinary education and does not diagnose or treat an individual animal. Always confirm medication names, doses and interactions with the veterinarian who knows your pet.
If your animal is struggling to breathe, collapsed, bleeding heavily, seizing, or has eaten something toxic, contact your vet or the nearest emergency clinic now.
Animal Poisons Helpline (AU) 1300 869 738 · Animal Poisons Helpline (NZ) 0800 869 738 · ASPCA Animal Poison Control (US) (888) 426-4435
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Ask A Vet articles are written by Dr Duncan Houston BVSc, a practising veterinarian, unless another author is named in the byline.



