NSAIDs for pets — the honest guide

The short answer

NSAIDs reduce inflammation by inhibiting cyclooxygenase enzymes (COX-1 and COX-2). Newer dog-specific NSAIDs preferentially inhibit COX-2, reducing the GI and renal side effects of older drugs while preserving anti-inflammatory and analgesic effects. They are the first-line treatment for most chronic pain conditions in dogs without contraindications.

How they work

COX-1 and COX-2 are enzymes that produce prostaglandins. COX-1 prostaglandins maintain GI mucosal protection, renal blood flow, and platelet function. COX-2 prostaglandins drive inflammation and pain. Older non-selective NSAIDs (aspirin, ibuprofen) inhibit both, producing GI ulceration and renal injury at unsafe rates in dogs.

Modern dog-specific NSAIDs preferentially inhibit COX-2, reducing the side-effect profile while retaining the analgesic effect. They are not entirely free of side effects, but the safety margin in dogs is substantial when used appropriately.

The dog-specific NSAIDs

• Carprofen (Rimadyl, Norocarp). The longest-established dog NSAID. Twice-daily dosing. Excellent track record; large body of safety data.
• Meloxicam (Metacam). Once-daily liquid or tablet. Particularly useful for once-daily oral dosing in fussy dogs because of palatability.
• Robenacoxib (Onsior). Highly COX-2-selective; once-daily. Designed for short-term use; some long-term experience.
• Mavacoxib (Trocoxil). Once-monthly dosing. Convenient for owners who struggle with daily medication, but the long elimination half-life means side effects, if they occur, are slow to resolve.
• Firocoxib (Previcox). Once-daily; common in US practice.
• Grapiprant (Galliprant). Newer mechanism (EP4 antagonist rather than classic COX inhibitor). Lower theoretical GI/renal risk; growing evidence.

All of these have similar efficacy at appropriate doses. The choice is often based on convenience, palatability, and the individual dog's response.

NSAIDs in cats

Cats metabolise NSAIDs differently from dogs and have a narrower safety margin. The current options:

• Meloxicam. Available in cat-specific formulations and dosing. Short-term use is widely accepted; long-term use is more controversial because of renal effects in older cats. Many vets use it cautiously long-term in cats with normal kidney function and frequent monitoring.
• Robenacoxib. Approved for cats in many countries; short-term use widely accepted; long-term experience growing.

For older cats with renal disease, gabapentin is often preferred over NSAIDs as the first-line analgesic. See gabapentin for cats.

Never share NSAIDs across species

• Ibuprofen, naproxen. Toxic to dogs and cats at human doses.
• Aspirin. Tolerable short-term in dogs but worst NSAID for canine GI; complicates subsequent prescription of safer NSAIDs (must wash out for 7-10 days).
• Paracetamol (acetaminophen). Toxic to cats at single doses; toxic to dogs at higher than carefully-calculated doses. Never use without explicit veterinary direction.
• Indomethacin, diclofenac, ketoprofen. Various; variably safe; never use without veterinary direction.
• Dog NSAIDs in cats. Carprofen at canine doses is dangerous in cats; the species metabolism differs.
• Cat NSAIDs in dogs. Less dangerous but doses do not translate; use the dog-specific formulation.

What to monitor

• Bloodwork before starting. Baseline kidney and liver function.
• Bloodwork at 6 weeks, then every 6-12 months. Long-term users.
• Watch for vomiting, diarrhoea, dark stools, reduced appetite. Signs of GI upset; stop the drug and consult the vet.
• Watch for increased thirst and urination. Signs of renal effects; warrant urgent reassessment.
• Avoid combining NSAIDs with corticosteroids. Combination dramatically increases GI ulceration risk.
• Avoid in dehydrated patients. Renal injury risk is elevated.

Editorial reference, not veterinary advice. — Dr. NRS, last reviewed 28 April 2026.