Onsior (Robenacoxib) is a nonsteroidal anti-inflammatory medication used in both dogs and cats to treat pain and inflammation associated with osteoarthritis and postoperative pain. It works by inhibiting the production of inflammatory molecules in the body. Onsior is available in tablets and injectable forms, and the dosage may need to be adjusted based on the animal’s response and any potential side effects such as gastrointestinal upset or liver and kidney damage.