I too have vestibular migraine. I’m on Topomax & take the generic which is topirimate. I’ve been on it since June 2014. My initial dose was 25 mg once a day & increased to 25 mg twice a day. This was done over the course of 4 weeks. My neuro-opthamalogist told me that the drug was difficult to deal with at first but to trust him & it would get better. I felt awful the first week or so that I was on it & then I felt like a million bucks ever since. My symptom for the first week or so was a terrible headache which was unusual for me because although I have MAV I don’t have headaches. I would give the dr a call if you’re considered about the side effects but for me has proved to be an awesome drug.