BACKGROUNDIt is unclear whether patients with elevated BP and acute headache require treatment with anti-hypertensive medication, anti-headache medication, or both. We determined the impact of migraine medication on blood pressure and pain scores among emergency department patients with moderate or severe migraine and elevated blood pressure.METHODSThis study uses data collected from four emergency department-based migraine clinical trials. Patients were included if they had moderate or severe migraine. Patients received one of the following medications or medication combinations: Metoclopramide + dexamethasone, metoclopramide + methylprednisolone acetate, metoclopramide + diphenhydramine, hydromorphone, or prochlorperazine+ diphenhydramine. Blood pressure and 0-10 pain scores were assessed before medication administration and 1 h later.RESULTSWe collected data from 729 patients. 13.3 % (97/729) had moderately elevated BP or worse. Among these patients, we identified an association between change in mean arterial pressure and change in pain (B coefficient=0.04,p=0.01) Among 53 study participants with elevated blood pressure but without a diagnosed history of hypertension, mean arterial pressure change was associated with pain score change (B. Among 44 patients with elevated blood pressure and a history of diagnosed hypertension, there was no association with mean arterial pressure (B coefficient=0.03,p=0.25). Among the 97 patients with moderately elevated blood pressure or worse, 73.2 % (95 %CI, 64.2-82.2 %) experienced an improvement in diastolic blood pressure and 78.4 % (95 %CI, 70.0-86.7) improved systolic blood pressure.CONCLUSIONIn this analysis of data aggregated from four ED-based migraine studies, improvement in pain and blood pressure was associated among patients with acutely elevated blood pressure but without diagnosed hypertension. Most patients with elevated blood pressure who receive headache medication will experience improvement in their blood pressure over the subsequent hour.PLAIN LANGUAGE SUMMARYMany patients present to emergency departments with headache and high blood pressure. A majority of these patients experienced blood pressure improvements upon treatment of their headache, and those with acutely elevated blood pressure but not diagnosed hypertension demonstrated an association between pain and blood pressure improvements. Instead of administering unnecessary anti-hypertensive medication, this research suggests that in a majority of patients, elevated blood pressure can be managed by treating the headache.