My daughter just had surgery, and was getting Reglan with Benadryl through her IV. She requested no Benadryl with the last dose, because she didn't want to be sleepy when her sister came to visit. Suddenly, her jaw clenched and her eyes rolled to one side (she said she couldn't control her face) and she became panicky, and fearful that the doctors wouldn't let her go home. She thought she was having a stroke or a seizure. An injection of Benadryl helped her to calm down, but she experienced tingling at the base of her neck and "felt funny" for a few days after...Now we know why they give the two drugs together!