Mabs, haven't had that one, but looking at the BNF I don't think I'd be too happy about it for a child.
We also had Pizotifen which is a similiar one to sanomigram, dixarit and had Naramig which are £24 for 6 tablets! I decide to stop taking all medication for migraine after the person I worked for who is at Roche gave me an article on pre-menstrual migraine ( obviously not your daughters case) that demonstrated that a cocktail of aspirin, paracetemol, caffeine and motilium was more effective than any migraine drug. It is sold in America as Excedrin Migraine, I tried it and it gave me such a migraine that lasted a week. It was the caffeine, as I don't have caffeine at all ( not intentional, just hate coffee etc)
Now I just take soluble aspirin and it works!! Got a migraine in the night, woke with a real pounder this morning, due on it 2/3 days, but keep taking aspirin and it works.
My mother, also a sufferer has tried it too and it works for her, unfortunately children cannot take aspirin until 16 now, used to be 12.
I sympathise. I have suffered from age 16 and DD from 8/9, they used to call it abdominal migraine for DD as she was too young to have proper migraine ( so the doc's said)