Summary of results B.

Use of rescue medication

Placebo comparators	Studies	Attacks treated	Treatment (%)	Comparator (%)	Relative risk (95% CI)	NNTp (95% CI)
Aspirin (m± metoclopramide) versus placebo	8	2922	44	65	0.68 (0.63 to 0.73) 4	8 (4.1 to 5.7)
Aspirin 1000 mg versus placebo	5	1881	42	63	0.67 (0.61 to 0.73)	4.8 (3.9 to 6.0)
Aspirin 900 mg plus metoclopramide 10 mg versus placebo	3	1041	48	69	0.69 (0.62 to 0.77)	4.7 (3.7 to 6.5)
Active comparators	Studies	Attacks treated	Treatment (%)	Comparator (%)	Relative risk (95% CI)	NNH (95% CI)
Aspirin (± metoclopramide) versus sumatriptan 50 mg or 100 mg	4	1340	49	43	1.1 (1.01 to 1.3)	17 (8.8 to 140)
Aspirin 1000 mg versus sumatriptan 50 mg	2	726	44	40	1.1 (0.92 to 1.3)	Not calculated
Aspirin 900 mg plus metoclopramide 10 mg versus sumatriptan 100 mg	2	614	55	46	1.2 (1.01 to 1.4)	11 (6.0 to 120)