Hi, I've been taking 100mg twice a day for 3 years. I also experience dry mouth once in awhile, but nothing too serious. I also take carb/levo, amitriptylin and comtan, so I'm not always sure which medication is giving me a particular side effect. I also have not had a single cold or flu since I've been treated for Parkinson's and I used to get sick all the time. Even when I am around friends and family who are sick, I never catch it (knock on wood). Good luck with your treatment!