Is There A Connection Between Mountain Dew And Absence Seizures?

Is there a connection between Mountain Dew and absence seizures? My niece has been experiencing seizures over the past several months. She feels a squeezing in her head and sounds are muffled, and she becomes nauseus. She usually lies down when this happens. Yesterday, during her trip home, she pulled off the road when the squeezing and muffling occurred. Her mother saw that my niece passed out during this episode. While she was at my house this week, I noticed that she drinks Mountain Dew all day long. She is 40 1/2 yrs. old. 5'2". weight guess - 140lb. She has been diagnosed with fibromyalgia. Because of excruciating back spasms, she has been taking quite a bit of Percocet.