... Lorazepam has been continually substituted. Each time I try it I get migraine headaches that cause blindness, dizziness, and continue in a string for several days. I keep getting told that Ativan and lorazepam are the same. But they are not, when I demanded to use Ativan vs substituting Lorazepam, I get good relief and never, not once have had a migraine. When I use lorazepam, I get a migraine every time. They simply cannot be the same... So what is the real difference? It can be miniscule, however there is something different because my body violently rejects to generics. I have tried this many time s because Ativan is so expensive... but can no longer tolerate the substitute for any cost.