Hämäläinen 1997b.

Study characteristics
Methods	Randomized, double‐blind, placebo‐controlled, 2‐way cross‐over trial of oral sumatriptan
Participants	Children or adolescents 8‐17 years with a diagnosis of migraine with or without aura meeting IHS 1988 criteria from 3 pediatric hospitals in the Greater Helsinki Area of Finland who had not benefited from previous migraine therapy. Participants were required to have 2 migraine attacks per month. None of the participants were using preventive therapy, but had already participated in previous placebo‐controlled trials with paracetamol and ibuprofen, dihydroergotamine, or both. Randomized (N = 31); medication not used (N = 4); 1 medication used (N = 3); withdrawn (N = 1); primary efficacy analysis (N = 23)
Interventions	Each participant treated 1 migraine attack at home with oral sumatriptan (50 mg for a body surface area of 0.75‐1.5 m2 (~6‐12 years of age) and 100 mg for a body surface area greater than 1.5 m2 (~>12 years of age) and 1 migraine attack with placebo in a randomized order. Rescue medications were permitted at any time.
Outcomes	Headache relief at 2 h (defined as a reduction in pain intensity by at least 50%) Pain‐free at 2 h Use of rescue medication Adverse events Other reported outcomes: Pain intensity difference (pain intensity before drug minus pain intensity at assessment time) Summed pain intensity difference (pain intensity difference times h elapsed from previous assessment Treatment preference
Headache severity scale	100 mm VAS
Funding source	Arvo, Lea Ylppo Foundation, and Academy of Finland
Publication	Journal
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: no information provided
Allocation concealment (selection bias)	Unclear risk	Comment: no information provided
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: "matching placebo. . . Each patient received two identical packages"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: missing outcome data balanced across intervention groups
Selective reporting (reporting bias)	Low risk	Comment: all expected outcomes were reported