So, can you take flexeril and effexor xr hours apart? same day, just not at the same time?

Yes, but since both medications cross the blood-brain barrier they can cause lethargy and cognitive effects which can be enhanced by both meds being in the system together. There is a theoretical possibility of a condition called serotonin syndrome but this is extremely unlikely. Closely monitor for any side effects and let your physician know of any concerns that arise.