I’ve had good luck with pantothenic acid (B-5, I think). When you first get that metallic taste in your mouth that signals the onset of a migraine, take two pantothenic acid capsules. Take another two in a half-hour. See if that helps. I think it has something to do with your histamine.
I’ll try that if I have another migraine. I’ve been on clonidine to prevent migraines and cannot remember when my last one was, it’s been years. Plus it makes you feel calm without the intoxicating effect of tranquilizers.
One of the docs told me it was a controversial med that he didn't believe in as it was an inert substance. I needed to find a compound pharmacy and insurance didn't cover it.