I take betablockers:
Started on Propranolol 40mg twice a day which worked wonders for first 3 months but then migraines started again
Just started Half Inderal LA 80mg once a day which is a slow release betblocker, take it in the morning and it slow releases all day - saves the high and low of taking two lots of tabs
FWIW - my mum takes Sanomigran (Pitzotifen) and has done for 15 years. She still gets occasional migraines but no where near the 2 per month she used to!!
Any more info just shout.
BTW - your sis isn't on the pill is she? I can't take any form of hormonal contraceptive as it exacerbates my migraine.
HTH