Cyproheptadine
"I was pregnant, I had to stop taking Relpax (at 2 x a month) for migraines and I made notes and found I had horrible pain 20 out of 30 days in the month.  For 2 months I suffered and my ob referred me to my neuro who referred to my ob and no one would help me.  A new neuro put me on Periactin 4mg once a day.  I started it on -I think day 2  of what usually is a 3 day migraine and it stopped.  I had only a faint sensation of a headache.  "