Hey guys, like was previously mentioned, i and we are not doctors, but i had been taking verapamil 180 and sandomigrane 0.5, this combo along with a cafergot taken when onset felt had helped me greatly, that and really cold water held in my mouth on the side of the headache, you would think "icecream headache", but it felt better, i would lay across chairs and lower my head to get the cold water to my upper teeth.
I never had any relief with oxygen or imitrex(nasal), good luck.