Could Taking Diclofanic Sodium Cause Passing Of Black Stool?

aoa hi during last 15, days i have taken diclofanic sodium 75 mg bd for pain in my knee,which was relieved but it has possibly resulted in passing of black and tarry stool without any offensive odour. what medecine now can be taken to rectify the sitation. a very minor pain remains in the abdomen . Hoping to receive early advice