I'm seventy and have had severe migraine all my life. I'm currently on my fifteenth cycle of Botox treatment and I also have a nerve stimulator. I mention these facts just to indicate that I've tried just about everything. There have been dozens of prophylactics over the years, from Amitriptyline to Epilim, Gabapentin to Topiramate. In every case, the side effects eventually proved so unpleasant and life draining that I had to give them up. Topiramate was very effective but it badly affected my memory and cognition and gave me five very painful kidney stones in three years and the hospital withdrew the drug. No kidney stones since.
Recently, I was prescribed Amlodipine for the second time and so far the results have been transformative. It's still early days, just five weeks, but I can't recall another period in my life when I've had zero migraines.