Hi. Levodopa and carbidopa can cause uncontrolled movements of parts of body and also GI upset such as nausea
, vommiting and diarrhea
. It cannot cause black tarry stools. U must have Stool R/E for presence of any blood in it. If there is blood in that a thorough physical examination had to be done with appropriate labs that include Blood CP, for decreased in haemoglobin
concentration PT & INR for any coagulation disorders. If there is blood in the stool a diagnostic endoscopy
had to be done for signs of ulcer or other problems.