I have been taking β-blockers to prevent my migraines and they do work, I'm only having one or two episodes a month now. After taking the beta blockers for more than two years I have experienced little side-effects, mainly dry eyes. But recently I have been sleeping badly and I started having nightmares. I don't really think that I have had a particularly stressful time in the past few weeks (I went through much worse periods) and yet I get these symptoms. I know that beta blockers can mess with your sleep and induce nightmares, so I was wondering if any of you had "delayed" side-effects with them?