I am not sure -- Trying to investigate-- Shortly after starting the med, I had strep throat and developed an unusual sinus condition where my sinuses do not drain in either direction. I have such "fullness" in my sinuses and throat that at times I feel as though I am drowning on my own secretions. I have had septoplasty and allergy testing to no avail. Now I think I can trace the symptoms back to beginning treatment with Lamictal.