Immitrex is not good - cleansing - they need to flush the body out. Use ice packs to soothe the rebound headaches - lay quiet with ice packs surrounding the head. It may take a while but it does respond. There is also something out there called: Pain RX by Hi Tech - google it - it works well. Take about three and in short time pain does lessen or disappear. You can repeat for several times during the day but I find it lessens the pain greatly so there is no need for anything harsh. Using ice with it will truly help that headache. I suffer from TBI so I know headaches.
If you need more info let me know - google jesichashope and direct the inquiry to the director - I will help you further.