My research today stems from my mother's (Parkinson's patient) 8 week bout of severe diarrhea. It started along with some occasional nausea and vomiting at about the same time she began taking Sinemet. I know these are two of the side effects of this drug but she has now been off the drug for nearly 5 weeks and is still experiencing severe diarrhea. She was hospitalized for 5 days, underwent tests including endoscopy, colonoscopy, barium ex-ray and bacteria all of which turned up no abnormalities. I am wondering if it is possible that she is still experiencing this as a side-effect of the medication. The drug companies are unable to tell me if this is a possibility or not. Anyone else experience adverse side effects that lasted this long?

I have not experienced nor heard of prolonged diarreah as a side effect of sinemet or other PD drugs. Wish I could help.

This is actually a post script;
I just checked the thread on gluten sensitivity. What is the possibility that your mother has developed celiac disease? I understand that it is possible to become sensitive or to begin showing overt symptoms of CD, even after many years of no apparent symptoms.

Has your mother been taking an antiobiotic and a proton pump inhibitor (ie nexium)? has she been tested for clostridium difficile or "C. diff"? Has she attempted to repopulate her gut with probiotics-can be obtained from activa or active culture yogurt or buttermilk.

Any new medication can be hard on your stomach but nausea and diarrhea usually level off and are not to the extreme you’ve described. When she was discharged from hospital what did the attending physician and nurses recommend? And is she still having severe diarrhea . . .? They did do a thorough investigation. Whomever ordered the tests must expect to see her again for follow-up; if you are in doubt give her doctor or the hospital a call and ask what you should do next. You are right to be concerned. If she has not improved she runs the risk of getting dehydrated. Insist on getting help. Push fluids in the mean time. Good luck. Guy