We tried creatine several years ago. It did not seem to help, and one side effect was rather horrible muscle cramps. It seemed that we could lessen or sometimes actually avoid those cramps by drinking a HUGE amount of water with the creatine (instead of just a glass of water).

Even though this did not help us, ours is just one person's experience. Since no one knows what causes PD, and symptoms vary considerably from person to person (meaning PD is really just a name given to a flexible bundle of symptoms), it could help others.