Less serious side effects include: 1  Loss of appetite. 2  Weight loss. 3  Nausea. 4  Vomiting. 5  Diarrhea. 6  Frequent urination. 7  Muscle cramps, painful and swollen joints. 8  Excessive tiredness. 9  Difficulty falling asleep. 10  Headache, nervousness, dizziness. 11  Depression, mood swings. 12  Vivid dreams.
Nausea can occur in dogs for many reasons, particularly when the digestive tract and nervous systems are out of balance. Stress can certainly play a role in nausea.
Ideally, a dog under steroids shouldnât get aspirin. Also, if the dog has stomach ulcers or a sensitive stomach, aspirin should be avoided. Aspirin Side Effects. Aspirin is a safe drug that may be used in dogs with fever, but in some dogs it may cause a few side effects such as: Vomiting; Upset stomach; Diarrhea