Celexa came first, and when the patent ran out, they played with the structure, took some things out, and made Lexapro. Reportedly it has fewer
side effects, but who knows if that's really true? I found Celexa easier to take myself, so it just goes to show. But the core of both drugs is the same. For me, the one drug that really put on the weight was Paxil. For others, it's different.