Night Terrors?

Night terrors terrify me. Last night Cale had his first one. Zach has had them in the past, but has not had one for awhile, thank goodness. It is a scary thing to witness, your precious little child turns into a raving, screaming, fighting little devil. Is there anything you can do? The only thing we do is keep trying to talk calm to them and make sure they don't hurt themselves. It seems like restraining them makes it worse, but I am so afraid they are going to hurt themselves. Cale's last night lasted what seemed like quite awhile and he is so upset I worry that he is going to pass out or have a stroke. He couldn't talk and seemed to be shaking, but after Eric and I trying to keep him safe, a brief moment outside (didn't want to wake all the neighbors), a little douse of cold water and watching Dora the Explorer he returned to his precious little self. I sat in the chair holding him and thank God he was okay. Does anyone have suggestions or know the cause? I worried because I gave him Robitussin to him for the first time, but that was at 4:30 pm and this was around midnight.