Can Dogs Eat Aleve? No — naproxen is highly toxic to dogs
✓ Reviewed against PDSA, Blue Cross & Animal PoisonLine guidance · Last updated: 2026-07-05
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The full picture
Naproxen (sold as Aleve, Naprosyn, Anaprox) is one of the most dangerous common human medications for dogs. Dogs metabolise naproxen extremely slowly compared to humans — the half-life in dogs is up to 74 hours versus 12–17 hours in humans — meaning the drug accumulates and causes prolonged toxicity. The toxic dose in dogs is very low: GI ulceration begins at approximately 5 mg/kg and kidney failure risk increases from 25 mg/kg. A standard Aleve tablet is 220mg, meaning a single tablet could be toxic in dogs under 44 kg (97 lb).
The mechanism of toxicity is the same as ibuprofen: naproxen inhibits prostaglandins that protect the stomach lining and maintain kidney blood flow. Stomach ulcers develop within hours to days, can progress to perforation, and kidney damage can require weeks of intensive hospitalisation to manage — if the dog survives. Do not give naproxen to a dog under any circumstances, and contact your vet immediately if accidental ingestion occurs.
If your dog has already eaten this
Call your vet or ASPCA Poison Control (888) 426-4435 IMMEDIATELY — even for one tablet. If within 1–2 hours of ingestion, your vet may induce vomiting. Bring the packet. Treatment includes activated charcoal, IV fluids for 48+ hours, GI protectants, and kidney monitoring bloodwork. Time is critical.
Risks to watch for
- Severe gastric ulceration and perforation
- Acute kidney failure
- Vomiting blood or black tarry stools (GI bleeding)
- Extreme lethargy and collapse
- Death without prompt treatment
Safe portion size
Zero. Never administer naproxen to a dog. For pain relief, consult your vet about dog-specific NSAIDs (meloxicam, carprofen, grapiprant).
Safer alternatives
- Meloxicam (Metacam) — most common vet NSAID in UK
- Carprofen (Rimadyl) — widely used US vet NSAID
- Grapiprant (Galliprant) — newer, gentler on GI tract
- Gabapentin for nerve or chronic pain — vet prescription
Why naproxen is more dangerous than ibuprofen in dogs
Both naproxen (Aleve) and ibuprofen (Advil, Motrin) are NSAIDs that inhibit prostaglandins, causing GI and kidney damage in dogs. Naproxen is significantly more dangerous for one specific reason: its half-life in dogs is 74 hours — versus 8 hours for ibuprofen and 12–17 hours in humans. This means naproxen stays in a dog's system for over three days, continuing to cause damage long after a single dose. Cumulative GI bleeding from even one standard tablet can be severe.
The therapeutic index (ratio of toxic to therapeutic dose) is also much narrower for dogs than humans. The dose at which naproxen becomes toxic in dogs is a fraction of what causes problems in people. A single 220mg standard-strength Aleve tablet is potentially toxic to dogs under 44kg (97lbs).
Naproxen sodium vs naproxen base
Most Aleve products contain naproxen sodium (a salt form) which is slightly heavier by molecular weight than naproxen base. The difference is small but toxicologists will ask which formulation was ingested. Standard Aleve = 220mg naproxen sodium. Prescription-strength naproxen sodium tablets come in 275mg, 375mg, 500mg, and 550mg doses. If your dog ate prescription naproxen, the dose concern is proportionally higher.
How does Aleve compare to other painkillers?
Naproxen (Aleve's active ingredient) is one of the more toxic human NSAIDs for dogs — it has a much longer half-life in dogs than in humans, meaning it stays active in the body far longer and builds up with repeat doses even at what would be a normal single human dose. This makes accidental repeat exposure (like a dropped pill picked up more than once) especially dangerous compared to a one-off ibuprofen exposure.
Does size or breed matter?
Toxic dose scales with body weight, so small and toy breeds cross into dangerous territory from a single tablet far more easily than large dogs. Dogs with any existing kidney or GI issues are at elevated risk regardless of size.