Some people with particular types of migraines, such as myself get investigated for Hughes Syndrome, otherwise known as Antiphospholipid Syndrome (APS).
These migraines do not react very well to pain relief until the blood is thinned: Here are two useful articles:
telegraph.co.uk/health/4400...
antiphospholipid.net/hughes...
telegraph.co.uk/health/9292...
Mary F x