Naproxen, a common nonsteroidal anti-inflammatory drug and the main component of Aleve, is not safe for dogs and cats, states Pet Poison Helpline. A small amount can cause severe ulcers, acute kidney failure and possibly coma and death. Symptoms of naproxen poisoning include vomiting, black stools, seizures and pale gums.
Nonsteroidal anti-inflammatory drugs, or NSAIDs, can help alleviate the joint pain, swelling and stiffness in dogs with arthritis, but there are special NSAIDs for dogs, advises WebMD. These include carprofen (Novox or Rimadyl), deracoxib (Deramaxx) and etodolac (Etogesic). To keep an arthritic dog comfortable, provide comfortable bedding and regular exercise, groom hard-to-reach areas, and provide a healthy diet that may include nutritional supplements, recommends the ASPCA.