I've been on several medications for my heart including Toprol. ...

I've been on several medications for my heart including Toprol. I've begun checking side effects on all to see which one may cause sleeplessness. I've been experience shortened sleep patterns, awakening in the early hours around 2:30am and unable to go back to sleep. I attributed this to external factors until recently when I missed all my medications for several days in a row and noticed I slept the nights through. I do have most of the other side effects mentioned, fatigue, lightheadedness, mood swings and memory problems. I also take Niaspan and Zetia.