Hello My 14 Year Old Daughter Has Recently Been Prescribed

Hello my 14 year old daughter has recently been prescribed Pizotifen for severe migraines, she started on 0.5mg for a week then was told to increase the dose to 1mg. Since then she has been feeling sick, has joint pain and is generally unwell. She also struggles to wake up in the morning even though she takes the medication at 6pm and doesn't go to bed late. Would it help if she were to stagger the doses through the day instead of taking 2 tablets together?