Hi,
With so many different medications, it is hard to tell what causes your nightmares.
Dreams, including nightmares and night terrors are created by your own subconscious to respond to interference and intrusions during sleep. In fact your nightmares are dreamt to help you sleep longer.
It is likely that one or more of your medicines create electro magnetic noise in your brain, therefore you need more vivid and more violent dreams to tell you when to move, change sleeping position, wake up, or stay asleep a bit longer.
Unfortunately many therapists and psychologists do not understand the interface between the subconscious and the brain during sleep.