My dog ate Aleve.
Treat it as serious.
Naproxen is far more dangerous to dogs than ibuprofen: it lasts days in their bodies (roughly a 3-day half-life vs hours in humans), so there is effectively no safe margin. One 220 mg tablet is a toxic dose for most dogs.
Any naproxen ingestion warrants a call: 855-764-7661Published thresholds (dogs)
GI ulceration is reported from about 5 mg/kg, and acute kidney injury from roughly 25 mg/kg. Those numbers are far lower than ibuprofen\u2019s because dogs clear naproxen extremely slowly (a half-life around 74 hours). One 220 mg Aleve crosses 5 mg/kg for any dog under about 97 lb.
Why "he seems fine" is misleading
Ulcers and kidney injury develop over 1-5 days while the drug is still circulating. The treatable window is early: decontamination and GI protectants work best before signs appear.
What NOT to do
Do not give any other pain reliever or "stomach protectant" without direction. Do not induce vomiting without professional guidance. Never dose naproxen to a dog on purpose.