for the main comparison.

Intranasal zolmitriptan 5 mg compared with placebo for acute cluster headache
Patient or population: adults with cluster headache Settings: community Intervention: intranasal zolmitriptan 5 mg Comparison: placebo
Outcomes	Probable outcome with intervention	Probable outcome with comparator	NNT or NNTH and/or relative effect (95% CI)	No of studies, attacks, events	Quality of the evidence (GRADE)	Comments
Pain‐free at 30 mins	320 in 1000	180 in 1000	NNT 6.9 (3.9 to 30)	2 studies, 228 attacks, 58 events	Low
Pain‐free at 15 mins	81 in 1000	32 in 1000	RR 2.6 (0.80 to 8.5)	2 studies, 228 attacks, 12 events	Very low
Headache relief at 30 mins	450 in 1000	260 in 1000	NNT 6.7 (4.2 to 17)	2 studies, 228 attacks, 82 events	Low
Headache relief at 15 mins	150 in 1000	70 in 1000	RR 2.2 (0.99 to 4.67)	2 studies, 228 attacks, 26 events	Very low
At least one AE	250 in 1000	160 in 1000	RR 1.8 (1.2 to 2.8)	1 studies, 102 attacks, 21 events	Very low
Serious AE	No events within 72 hours of study medication
CI: Confidence interval; NNT: number needed to treat; RR: relative risk; AE: adverse event
GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate.

Evidence downgraded because of threat from potential publication bias and chance effects with modest effect size and small numbers of events.