Awhile ago I listed the things I take and how when I stopped benadryl for awhile I could sure tell the difference in a bad way. Then I restarted the 1/2 doses of benadryl. Sinemet works so much better with a little bit (half a tab) of Benadryl. However, I was just using the drug interaction tool at medscape and for the 1st time I input benadryl...whoops! Come to find out that my little half a dose of benadryl is known to increase the efficacy of levadopa, BUT it raises the risk of TARDIVE DYSKINESIA!!! Just in case anyone else is taking benadryl and didn't already know that risk is why I am posting this. I am going to try again to quit the benadryl, just because TD is my worst fear, next to a spider crawling across my arm.