Lisinopril
"I had headaches since around middle school several times a week.  Never had a doctor who thought much about them, so I just stayed quiet and lived with them.  No over-the-counter medication helped.  I woke up with them.  I developed high blood pressure and my doctor prescribed lisinopril 10 mg.  Soon I realized I was no longer having any headaches -- zero.  I'm so happy we stumbled upon this.  I have told my doctor how much it has helped my headaches so that she remembers it for the next patient who might have constant headaches with no relief."