Methods	Multicentre, randomised, double-blind, placebo-controlled, parallel-group. Single dose to treat single attack Medication administered when migraine headache pain was of moderate or severe intensity Assessments at 1 and 2 h after dosing Second dose of study medication available after 1 h if participants had inadequate relief Alternative rescue medication (excluding ergotamine) was available if relief was still inadequate after 2 h
Participants	Aged 18 to 65, meeting IHS criteria for migraine (1988) with or without aura. At least 1-year history of migraine with a maximum of 6 attacks per month Participants receiving migraine prophylaxis were required to withdraw from prophylactic therapy at least 2 weeks prior to randomisation Ergotamine preparations were not to be used within 24 h of taking test medication N = 235 (216 with moderate or severe baseline pain intensity) M 43, F 192 (82%) Mean age 41 years Without aura 65%
Interventions	Sumatriptan 6 mg, n = 155 (147 with moderate or severe baseline pain intensity) Placebo, n = 80 (69 with moderate or severe baseline pain intensity)
Outcomes	Headache relief (at 1 h) and 2 h (1 h after optional 2nd dose) Pain-free (at 1 h) and 2 h (1 h after optional 2nd dose) Improvement in nausea, vomiting, and photo/phonophobia at 1 h Adverse events Withdrawals
Notes	Oxford Quality Score: R2, DB2, W1. Total = 5.
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer-generated randomisation code
Allocation concealment (selection bias)	Low risk	Patients were entered in ascending sequential order of patient number at each centre
Blinding (performance bias and detection bias) All outcomes	Low risk	Placebo was provided in identical syringes
Study size	Unclear risk	Treatment groups 50 to 200 participants