I have had the same symptoms as a result of Trazadone for sleep - when I would get up from bed or stand up abruptly from sitting I sometimes become dizzy, lightheaded. This is a known side effect from Trazadone called hypostatic hypertension (sudden increase in blood pressure upon standing). I can manage it at a lower dose of Trazadone (50mg) but it’s much worse when on higher dosages or when dehydrated (I had several fainting spells last summer). My doctor wants me off Trazadone completely but I take it for my insomnia - difficult trade off.