Time frame: Baseline (28 days before randomization) and Continuous treatment period (Day 1 up to Day 225)
If aura of migraine, migraine attack or non-migraine headache attack occurred in study, these rescue drugs were permitted:analgesics, non-steroidal anti-inflammatory drugs (NSAIDs),ergotamines,triptans,antiemetics. Drugs with restricted treatment days of less than (<) 15 days per month (28 days):analgesics, NSAIDs,combination of rescue drugs and those with <10 days per month:triptans,ergotamines, opioids,combination analgesics. Average calculated as total number of monthly rescue-drug treatment days divided by the total number of days of assessment and multiplied by 28, where a month = 28 days.