I have been getting cluster migraines for as long as I can remember. Starts with a single bright light that spreads to the point where I cannot see. As the lights fade, usually around 20 to 30 minutes, the intense pain and nausea begins and can last for days. If I can get down a couple of Excedrin Migrain before the lights get to bad the pain does not get too intense and I can cope pretty much as normal. Needless to say I carry the stuff every where I go.