Lithium
"I have been suffering from horrible daily chronic cluster/migraine for 30 years with absolutely no relief. My neurologist refused to put me on lithium. According to him it's an out of date medicine that belongs in the past. I have been on lithium for 2 weeks and have had my first headache free period in so many years. I went to my PCP and he gave me lithium. If you are not satisfied with current treatment, I do recommend this for chronic clusters/ migraines. "