Monitoring of acute migraine attacks: placebo response and safety data

In the course of evaluating the safety and efficacy of an investigational compound for acute migraine headaches, a large number of patients received placebo at a single site, offering the opportunity to characterize subjective and clinical physiologic responses of migraine patients to placebo in a controlled environment. In a single-site, double-blind, placebo-controlled study, 67 patients reported to the clinic while suffering a moderate to severe acute migraine headache and received oral placebo. For 6 hours after treatment, a continuous electrocardiogram (ECG) was performed, and headache severity, adverse events, and vital signs were recorded. Patients returned and repeated the procedure when free from pain. A headache was considered to be improved if its severity dropped to "mild" or "none." Twenty-five patients (37%; 95% CI: 26% to 50%) experienced headache improvement within 2 hours of receiving placebo, and 32 patients (48%: 36% to 60%) improved within 4 hours. There were no clinically important ECG changes during the migraine visit, and there were no clinically relevant differences in vital signs between the migraine and pain-free visits. Thus, a substantial placebo response occurs in migraine headache. Hemodynamic and ECG parameters are unchanged between migraine and pain-free states.