Boy am I glad I found this site! My dr. put me on Levaguin 750 mg for 5 days for a sinus infection. The first night I only slept a couple hours at time, woke up anxiety ridden, had strange dreams...The second evening I started having heart palpitations and "band around the chest" type pains that thankfully subsided after a short time. But that night I couldn't stay asleep for more than an hour at a time, but I wasn't at all tired the next morning (!). However I was NAUSEATED big time. By the 3rd afternoon all I could stand to do was lie in bed and stare at one spot on the wall. The dr. told me to stop taking the Levaquin and force fluids. That was yesterday and I'm slowly feeling better, but boy, I'll take a sinus infection any day over those pills!