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.
1 Burning Bush: Plants toxic to dogs and can cause vomiting, nausea and skin reactions.  Butttercup: The entire plant is toxic to dogs, especially the leaves. Varied digestive tract related symptoms in dogs such as stomach pain and diarrhea. May cause a skin reaction.