• Difference in migraine headache periods during the active treatment period as compared to the placebo treatment period, per subject.
  

• Reduction of migraine attack frequency during each 28-day interval of the active treatment period as compared to each 28-day interval of the placebo treatment period, per subject. Individual migraine attacks are separated by 48-hours pain free time. A
  
• Reduction in days using an acute headache treatment during the active treatment period as compared to the placebo treatment period, per subject.
  

Inclusion Criteria:

• Subjects who are male or female between the ages of 18 and 65, inclusive
• Subjects who have a history of migraine with or without aura as defined by IHS criteria, for at least one year prior to screening
• Subjects who experience between 3 and 10 migraine attacks per month, for the three months preceding screening
• Subjects who have no more than 15 headache days per month
• Subjects who have been on a stable dose (no clinically significant changes) of all daily medications, for any indication, from 28 days prior to screening through the duration of the trial.
• Women who are using, or agree to use for the duration of the study, a medically acceptable form of contraception (as determined by the investigator), if female of childbearing potential.
• Subjects who are able to understand and comply with all study requirements
• Subjects who provide written informed consent prior to any study procedures being performed.

Exclusion Criteria:

• Women who are pregnant or lactating
• Subjects with an abnormal ECG that, in the investigators opinion, would expose them to increased risk of adverse events or interfere with study drug and/or analysis of efficacy/tolerability (subjects with QTC interval greater than 450ms will be excluded)
• Subjects currently taking, or have taken within the thirty days prior to screening, any neuroleptics > 1 day per week (such as Geodon, Zyprexa, Compazine, Phenergan, Seroquel and other drugs in the same class)
• Subjects currently taking or have taken within 4-weeks prior to screening any medication for the prevention of migraine
• Subjects who have failed more than two adequate trials of migraine prophylaxis, as determined by investigator
• Subjects who experience significant orthostatic hypotension, as determined by the investigator
• Subjects who, in the investigators opinion, have a history or have evidence of a medical condition that would expose them to an increased risk of a significant adverse event or would interfere with the assessments of efficacy and tolerability during this trial
• Subjects who, in the investigators opinion, have a history or have evidence of a psychiatric condition that would expose them to an increased risk of a significant adverse event or would interfere with the assessments of efficacy and tolerability during this trial.
• Subjects who have participated in an investigational drug trial in the 30 days prior to the screening visit