Tried all sorts of drugs for mine, no good. Pethadine, mercyndol, nurofen, ibuprofen, panadine forte (lol).
A good old fashioned 14hr nap normally sorts it.
In saying that I haven't had one for at least a year. Touch wood
Never found out what they were brought on by - food doesn't vary too much, never been stressed in my life, always get good amount of sleep, etc. I think it's just a genetic thing that can happen - some get them some dont. Lots of people think their headache is a migraine and these people annoy me.