Methods	Participants recruited from 33 international neurology centres; in-patient based study R, DB, three-period cross-over study; 18 h washout One headache episode treated with each of two treatments
Participants	IHS diagnosis of cluster headache N = 157 randomised, 134 in efficacy analysis Mean age 41 ± 9 years 87% men Headache type: 72% episodic
Interventions	Sumatriptan 6 mg, subcutaneous, n = 92 Sumatriptan 12 mg, subcutaneous, n = 88 Placebo, n = 88 Patients received 0.5 mL injection within 10 min of headache episode of at least moderate intensity Rescue medication permitted after 15 min
Outcomes	Primary: Pain relief to mild or none at 10 min on a five-point scale Secondary: Headache relief at 5 and 15 min; pain-free at 15 min; associated symptoms; overall functional disability; adverse events/withdrawals; use of rescue medication
Notes	Oxford Quality Score: 4 (R2, DB1, W1)
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Yes	Generated by computer
Allocation concealment?	Unclear	Not described
Blinding? All outcomes	Unclear	Not described