STUDY SUMMARY
Multiple RCTs highlight aspirin’s efficacy
The 2013 Cochrane reviewers used the same 13 good-quality, double-blind RCTs involving 4,222 participants as the earlier review; no new studies that warranted inclusion were found. A total of 5,261 episodes of moderate-to-severe migraine were treated with either aspirin alone or aspirin plus the antiemetic metoclopramide.1
Five studies had placebo controls, four had active controls (eg, sumatriptan, zolmitriptan, ibuprofen, acetaminophen plus codeine, and ergotamine plus caffeine), and four had both active and placebo controls. Primary outcomes were painfree status at two hours and headache relief (defined as a reduction in pain from moderate/severe to none/mild without the use of rescue medication) at two hours. Sustained headache relief at 24 hours was a secondary outcome.
Patients self-assessed their headache pain, using either a four-point categorical scale (none, mild, moderate, or severe) or a 100-mm visual analog scale. On the analog scale, less than 30 mm was considered mild or no pain; 30 mm or more was considered moderate or severe.
Study participants were ages 18 to 65 (mean age range, 37 to 44), and their symptoms met International Headache Society criteria for migraine with or without aura.9 All participants had migraine symptoms for at least 12 months, with one to six attacks of moderate to severe intensity per month prior to the study period.
In six studies (n = 2,027), investigators compared either 900- or 1,000-mg aspirin alone with placebo. For both primary outcomes, aspirin alone was superior to placebo, with a number needed to treat (NNT) of 8.1 for two-hour painfree status and 4.9 for two-hour headache relief. In three studies (n = 1,142), aspirin was superior to placebo for 24-hour headache relief, with an NNT of 6.6.
Aspirin plus metoclopramide was also better than placebo for primary and secondary outcomes, with an NNT of 8.8 for two-hour painfree status, 3.3 for two-hour headache relief, and 6.2 for 24-hour headache relief. Based on subgroup analysis, aspirin plus metoclopramide was more effective than aspirin alone for two-hour headache relief but equivalent for two-hour painfree status and 24-hour headache relief. The addition of metoclopramide to aspirin significantly reduced nausea and vomiting.
In two studies (n = 726), aspirin alone was equivalent to sumatriptan 50 mg for reaching painfree and headache relief status at two hours. Two additional studies (n = 523) compared aspirin plus metoclopramide with sumatriptan 100 mg and found them to be equal for two-hour headache relief, but the aspirin combination was inferior to the triptan for painfree status at two hours (n = 528). Data were insufficient to compare the efficacy of aspirin with zolmitriptan, ibuprofen, or acetaminophen plus codeine.
There were no reports of gastrointestinal bleeding or other serious adverse events attributable to aspirin therapy. Most adverse effects were mild or moderate disturbances of the digestive and nervous systems, with a number needed to harm of 34 for aspirin (with or without metoclopramide) versus placebo.
WHAT’S NEW?
A reminder of aspirin’s efficacy in treating migraine
The update of this meta-analysis confirms that high-dose aspirin (900 to 1,000 mg) is an effective treatment for migraine headache in adults ages 18 to 65. The addition of metoclopramide reduces nausea and vomiting but offers little if any benefit for headache/pain relief.
Continue reading for the caveats and challenges to implementation...