I get cluster headaches which aren't migraines (they're somehow worse!) and I take a daily verapamil (prescription) but it has completely gotten rid of the headaches for me. Verapamil can also work on migraines I've read but I'd recommend finding a neurologist that knows more than the average doctor about headaches that would be more likely to prescribe it or something more out of the box like it. Verapamil can take a couple weeks to start working so make sure you have an abortive system in place like imitrex nasal spray or injection while it builds up in your system if you try it.

Good luck.