I used Verapamil to successfully end the worst cluster I have ever had, 4 months with as many as 7 in one day. we started at 180 mg a day and increased dosage in 60 mg increments until they stopped around 480 mg. but the side effects, mainly lethargic and a heart tic made me stop taking it after 2 months. THE GREAT NEWS! My headaches, while still occurring are much less severe, much shorter and much more infrequent. if they were 10's before. they are 1's and 2's now, duration down from 30-90 minutes to less than 10 minutes. Frequency from 3 to 7 a day down to less than once a day, usually nocturnal, about an hour after i go to sleep. It took about a month for all the side effects of the drug to wear off and now I feel like my old self, my energy has returned, I have returned to work and my life is great. I take absolutely no medication now and just deal with these little baby clusters now as a minor annoyance instead of a life altering disability