Axert

My 16 yo son took several doses of Axert within the past month.  He developed severe faintness upon rising - standing from sitting, sitting from laying down, blurry vision, eyes crossing, chest heaviness/pressure, extreme fatigue, tingly feeling in legs.  Taking Axert coincided with an increase in his exercise regime.  He only gets migraines from hard exertion in exercise.  He is very fit and healthy, but there is a strong family history of coronary artery disease, high cholesterol, high blood pressure, connective tissue disease and sensitivity to prescription drugs.  Pediatrician is clueless, neurologist thinks his symptoms are a migraine variant, ped cardiologist thinks is is due to emotional duress (?) or dehydration (also?, nonexistent, drinks a lot and had two bags of saline in ER less than a week ago).  When I ask about a reaction to Axert they all either tell me that they know nothing about the drug of any negative effects or look at me like I am loony.  Help anyone?