A comparative trial of three agents in the treatment of acute migraine headache. STUDY OBJECTIVES: A study was conducted to evaluate the relative efficacy of three non-narcotic agents, chloropromazine, lidocaine, and dihydroergotamine, in the treatment of migraine headache in an emergency department setting. DESIGN: The trial was randomized and single blinded. SETTING: The study was conducted in two university-affiliated EDs. TYPE OF PARTICIPANTS: All patients had an isolated diagnosis of common or classic migraine. INTERVENTIONS: Patients were pretreated with 500 mL (IV) normal saline before randomization. Study drugs as administered were dihydroergotamine 1 mg IV repeated after 30 minutes if the initial response was inadequate; lidocaine 50 mg IV at 20-minute intervals to a maximum total dose of 150 mg as required; or chloropromazine 12.5 mg IV repeated at 20-minute intervals to a total maximum dose of 37.5 mg as required. Patients were asked to grade headache severity on a ten-point scale before and one hour after the initiation of therapy. Follow-up by phone was sought the following day. MEASUREMENTS AND MAIN RESULTS: Of 76 patients completing the trial, 24 were randomized to receive chloropromazine, 26 to receive dihydroergotamine, and 26 to receive lidocaine. Reduction in mean headache intensity was significantly better among those treated with chloropromazine (P less than .005). Persistent headache relief was experienced by 16 of the chloropromazine-treated patients (88.9%) contacted at 12 to 24 hours follow-up compared with ten of the dihydroergotamine-treated patients (52.6%) and five of the lidocaine-treated group (29.4%). CONCLUSION: The relative effectiveness of these three antimigraine therapies appears to favor chloropromazine in measures of headache relief, incidence of headache rebound, and patient satisfaction with therapy. 