Don't know about adavan but have gone through many flashback cycles over the past 20 years. What helps me is recognizing my triggers and using relaxation techniques and grounding techniques, going to the nearest restroom and pulling out my journal and writing down what I am seeing, hearing and so on and taking out my walkman and listenig to relaxing music or a relaxation visualization tape made by my therapist and me during therapy sessions. Once The flashback passes I am usually tired but ok because my relaxation stuff and writing keeps me calm during the flashbacks so I can just continue on with my day.