What is a yellow round pill with a m on one side and 751 on the other

Not Medical Advice: A round yellow pill with M on one side & 751 on other is Cyclobenzaprine (10mg; brand name Flexeril). It is used as a muscle relaxant.

Wednesday, May 23 2012
Source: http://www.drugs.com/search.php?q=Cyclobenzaprine