Hämäläinen 1997a.

Study characteristics
Methods	Randomized, double‐blind, placebo‐controlled, 3‐way cross‐over trial of ibuprofen, paracetamol, and placebo
Participants	Children or adolescents < 18 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 found previous therapy for migraine unsatisfactory. Participants were required to have 2 migraine attacks per month lasting 2 h or more. Randomized (N = 106); lost to follow‐up (N = 2); medication not used (N = 16); 1 medication used (N = 5); 2 medications used (N = 8); withdrawn (N = 9); intention‐to‐treat analysis (N = 88); primary efficacy analysis (N = 66)
Interventions	Each participant treated 1 of 3 migraine attacks with either oral paracetamol (15 mg/kg), oral ibuprofen (10 mg/kg), or placebo. The active drugs and matching placebo were supplied by the University Pharmacy of Helsinki in 3 mixtures containing peppermint water, black currant syrup, sugar syrup, and either 30 mg/ml paracetamol or 20 mg/ml ibuprofen, or, as a placebo, cellulose. Each participant received a package of 3 identically numbered bottles and a plastic 10 ml syringe for exact weight‐based dosing (0.5 ml/kg, maximum dose 30 ml).
Outcomes	Headache relief at 2 h (defined as severe or moderate (a grade of ≥ 3) to at least 2 grades lower Pain‐free at 2 h Use of rescue medication within 2 h Adverse events Other reported outcomes: Headache relief and pain‐free at 1 h after treatment Patient preference
Headache severity scale	Participants were allowed to choose between the 5‐faces pain scale (5 severe, 4 to 3 moderate, 2 mild, 1 no pain) or the 100 mm visual analogue scale (VAS). The VAS (0 to 100) data were transformed to a nominal scale: grade 1: 0 to ≤ 12; grade 2: 12 to ≤ 37; grade 3: 37 to ≤ 62; grade 4: 62 to ≤ 87; and grade 5: 87 to ≤ 100
Funding source	Not specified
Publication	Journal
Notes	All additional children and adolescents with any data on efficacy were included in the intention‐to‐treat analysis, which was performed without regard to pain intensity at the start of the attack.
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: "[T]he active drugs and matching placebo were supplied by the University Pharmacy of Helsinki in three mixtures containing peppermint water, black currant syrup, sugar syrup, and either 30 mg/ml paracetamol or 20 mg/ml ibuprofen, or as placebo (cellulose). Each participant received a package of three identically numbered bottles and a plastic 10 ml syringe for exact weight‐based dosing (0.5 ml/kg; max 30 ml)."
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 reported