Extreme dreams symptoms and conditions

I took z-pak this week, and I've had some stomach cramps. The first night I took it it was the worst, but they've gradually gotten better.
But does anyone know if it can cause vivid dreaming? Every night I've taken it I've had some extreme dreams (one included both Obama and my HS sweetheart, if that helps to explain how intense they were). Has anyone else had this problem? I tried to find out if this was a common side effect, but couldn't find anything.