I don't know but he's sleeping better adding Benedryl. He's still waking up in the night though. I moved his Sinemet to 5pm to see if that helps. It's a hit or miss at this point. It is listed as a side effect and this started about two weeks after starting Sinemet. Ugh. His doc almost took him off it as soon as I said something and Jim said no. If he's not sleeping in a week then he'll have to try something else.