 4. Use of any prophylactic drug therapy for headache control within 4 weeks of screening e.g., anticonvulsants, mood stabilizers, beta-blocker, antidepressants, muscle relaxants, botulinum toxin. Subjects taking any of these medications for an indication other than headache e.g., a beta-blocker for hypertension will require medical monitors approval prior to initiation of the Run-In Period. 