Chronic migraine is defined as 15 or more headache days per month, with at least 8 of those days fulfilling migrainous criteria (moderate to severe pain, unilateral or pulsating quality, photophobia or phonophobia, nausea), for at least 3 consecutive months. The condition affects roughly 1 to 2 percent of adults globally and produces substantial disability across work, family and social function.
The PREEMPT 1 and PREEMPT 2 phase 3 trials (Pooled REsearch Evaluating Migraine Prophylaxis Therapy) established the dosing protocol that secured US FDA approval of Allergan Botox for chronic migraine in October 2010. The protocol injects a fixed 155 unit total dose at 31 specific anatomic sites across 7 muscle groups: corrugator (5U each side), procerus (5U), frontalis (5U each at 2 points per side for 20U total), temporalis (5U each at 4 points per side for 40U total), occipitalis (5U each at 3 points per side for 30U total), cervical paraspinal (5U each at 2 points per side for 20U total), and trapezius (5U each at 3 points per side for 30U total). Optional follow-the-pain dosing can add up to 40 additional units (max 195U) at temporalis, occipitalis and trapezius sites where the patient reports localized pain.
At Kind Global Clinic Myeongdong, both co-directors personally administer the PREEMPT protocol — there is no nurse delegation, no junior-doctor rotation. Patient eligibility is confirmed against the PREEMPT inclusion criteria: 15 or more headache days per month with 8 or more migrainous days, prior failure of 2 or more oral preventive medication classes, and no contraindication to botulinum toxin. Brand is always Allergan Botox to match the FDA-approved indication; lot number, exact unit count per of the 31 sites and patient headache diary baseline are recorded on the patient chart. The 12-week dosing interval is fixed per the PREEMPT regimen — patients typically see meaningful headache-day reduction by cycle 2 or 3 (week 12 to 24), with the published mean response being a 50 percent or greater reduction in headache days per month in approximately half of treated patients.