# Onsior (Robenacoxib) Dose for Cats & Dogs: Strengths & Dose Calculator

> Onsior is robenacoxib from Elanco: 6 mg tablets for cats at 1 mg/kg once a day, and a 20 mg/mL injection for cats and dogs at 2 mg/kg under the skin once…

- Source page: https://wevet.in/vet-products/onsior-robenacoxib/
- Type: Vet product
- Publisher: WeVet
- Updated: 2026-11-02
- Medically reviewed by: Dr. Ravi Baraiya, B.V.Sc. (2026-11-02)
- Audience: veterinarians and veterinary students

Onsior is robenacoxib from Elanco: 6 mg tablets for cats at 1 mg/kg once a day [1], and a 20 mg/mL injection for cats and dogs at 2 mg/kg under the skin once a day [2] — both for post-operative pain, for a maximum of 3 days [1][2].

- Brand: Onsior
- Contains: Robenacoxib
- Company: Elanco
- Label species: Cats, Dogs
- Data from: USA (FDA label)

## Strengths

- Onsior 6 mg tablet for cats: Robenacoxib 6 mg per tablet (verified, [1])
  - 2.5–6 kg: 1 whole tablet once daily
  - 6.1–12 kg: 2 whole tablets once daily
- Onsior injection 20 mg/mL: Robenacoxib 20 mg per mL (verified, [2])

## Dose by species

| Species | Use | Dose | Route | How often | Basis |
|---|---|---|---|---|---|
| Cats | Post-operative pain (tablets) (Cats ≥ 2.5 kg and ≥ 4 months old.) | 1 mg/kg [1] | PO | Once daily · Maximum 3 days | Label |
| Cats | Post-operative pain (injection) (First dose about 30 minutes before surgery.) | 2 mg/kg [2] | SC | Once daily · Maximum 3 days | Label |
| Dogs | Post-operative pain, soft-tissue surgery (injection) (First dose about 45 minutes before surgery.) | 2 mg/kg [2] | SC | Once daily · Maximum 3 days | Label |

## Label directions

- Tablets (cats): 1 mg/kg once a day for up to 3 days — 1 tablet for 2.5–6 kg, 2 tablets for 6.1–12 kg [1].
- Injection: 2 mg/kg SC once a day for up to 3 days; first dose about 30 minutes (cats) or 45 minutes (dogs) before surgery [2].

## Warnings and precautions

- Do not use the tablets in cats under 2.5 kg (5.5 lb) [1].
- Robenacoxib can prolong the QT interval [1].
- Do not give with any other oral or injectable NSAID or corticosteroid [2].
- Stop if a cat’s appetite drops or it becomes lethargic [2].


Interactive dose calculator (strength prefilled only when confirmed): use the page link above.

## Frequently asked questions

### What is the Onsior dose for cats?

Tablets 1 mg/kg once a day, or injection 2 mg/kg SC once a day — maximum 3 days either way [1][2].

### How many Onsior tablets for a 4 kg cat?

Cats of 2.5–6 kg get 1 whole 6 mg tablet once a day [1].

### Can Onsior be used in dogs?

The US injection is labelled for dogs after soft-tissue surgery at 2 mg/kg SC once a day for up to 3 days [2].

## References

[1] ONSIOR (robenacoxib) 6 mg tablets for cats — FDA labeling — Animal Drugs @ FDA — US label, Elanco (2026). https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadLabeling/743
[2] ONSIOR (robenacoxib) injection — FDA labeling — Animal Drugs @ FDA — US label, Elanco (2026). https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadLabeling/745
[3] Nonsteroidal Anti-inflammatory Drugs in Animals — Merck Veterinary Manual — S. H. Edwards (updated Sep 2024) (2024). https://www.merckvetmanual.com/pharmacology/inflammation/nonsteroidal-anti-inflammatory-drugs-in-animals

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Numbers in [brackets] cite the references above. For veterinary professionals. Information supports — never replaces — clinical judgement; always check the current product label and local regulations.
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