The neurologist my daughter (15 years old and a good size adult weight) saw recommended amitriptyline starting at 10 mg and moving to 20 mg after a week. We tried if for a few of days but it made her fatigue worse. Since the sleep/fatigue issues are worse than the headaches, we switched her back to trazodone she was one.

Supplement wise, she recommended the following for headaches:

B2 (riboflavin) – 200 mg x2 daily
CoQ10 – 25-75mg x2 daily
Feverfew (don't have s specific dose on this one)
Migrelief – 1 tablet x2 daily - Migrelief is a combo of B2, Magnesuim and feverfew
Avoid - caffine - though if you don't usually use caffine - it can help with a bad headache