Propranolol
"I've been taking 100 milligrams of propranolol for 1 year now and it has reduced the number of migraines significantly.  I still take Imitrex when I do get a migraine but not as often. Propranolol does however cause impotence. I have seen the number of comments regarding weight gain but I actually started taking Cymbalta at the same time and lost 30 pounds so I have no comment on that issue."