Cephalalgia : an international journal of headache
-
The objective was to assess the placebo response in randomized clinical trials of analgesics in the treatment of migraine attacks. We included placebo-controlled studies that used the criteria of the International Headache Society for the diagnosis of migraine and headache response as the primary efficacy parameter. ⋯ In conclusion, the average headache response rate to placebo was 30% in randomized clinical trials of analgesics in migraine with a tremendous variation among studies. Placebo response rates vary with the choice of primary efficacy measure as well as patient characteristics and study design.