Efficacy of CLORazepate for the Treatment of MIGraine Attack in the Emergency Room

Inclusion Criteria: * Age from 18 to 70 * Patient suffering migraine or probable migraine (diagnosis made by neurologist according to IHCD3) * Present migraine attack lasting ≤ 72 hours * Headache intensity moderate or severe on the verbal ordinal scale (4 levels: no headache, mild, moderate or severe) * Patient requiring parenteral treatment * Affiliation to the French Health-care System "sécurité sociale" Exclusion Criteria: * abnormalities of neurological exam, seizure, fever (≥ 38°C), and/or SBP≥180 and/or DBP≥110 mmHg * suspicion of secondary headache * inability to understand the consent or scales * pregnancy or breast-feeding * known respiratory or liver insufficiency * acute alcohol consumption or alcoholism * myasthenia * Patient requiering treatment with sumatriptan SC, particularly in the event of failure of an anti-inflammatory drug at an effective dose taken within 6 hours * recent use of benzodiazepines (\< 24h diazepam, clonazepam, clorazepate ; \< 6h alprazolam, lorazepam, midazolam) * recent use of pain killers (\< 2h) * contraindication to any of the investigational medication * contraindication to intravenous access * previous participation to this study