Migraines in the Emergency Department: Which Therapy Is Best?
Posted 03/12/2009
Introduction
Patients with a complaint of headache accounted for 2.8% of all US emergency department (ED) visits in 2006 -- almost 3.4 million visits.[1] The vast majority of these visits were for primary headaches not secondary to underlying discrete causes such as meningitis or subarachnoid hemorrhage. After ruling out secondary causes and diagnosing a primary headache, the emergency physician must decide on therapy. Variations in therapy for migraine are substantial. In a 2002 study, Vinson[2] reported that 3 dozen agents alone or in combination, were commonly used in US EDs to treat migraine.
The ideal medication for migraine would be highly and rapidly effective, well tolerated, and inexpensive. Although parenteral triptans and opioids are often used for the treatment of primary headaches, antiemetic dopamine antagonists such as prochlorperazine and metoclopramide are among the most efficacious and available analgesics for migraine. Prochlorperazine and metoclopramide have few contraindications, do not cause significant orthostatic changes, and do not require cardiac monitoring. Because few comparative studies of these 2 drugs exist, most emergency physicians choose one or the other, based largely on personal preference. In 2 previous trials,[3,4] both published more than 10 years ago, prochlorperazine was felt to be the superior agent. However, doses of metoclopramide used in those studies may have been suboptimal.
A Randomized Controlled Trial of Prochlorperazine Versus Metoclopramide for Treatment of Acute Migraine
Friedman BW, Esses D, Solorzano C, et al.
Ann Emerg Med. 2008;52:399-406
Summary
In the October 2008 issue of the Annals of Emergency Medicine, Benjamin Friedman and his colleagues reported the results of their randomized, double-blind clinical trial that compared 10 mg of intravenous prochlorperazine with 20 mg of intravenous metoclopramide for the treatment of adults with acute migraine. Both agents were preceded by the administration of 25 mg of intravenous diphenhydramine to lessen the likelihood of akathisia, a side effect that is common with both study medications. The primary outcome measure was the change in pain intensity 1 hour after drug administration, measured by an 11-point numeric pain-rating scale. Secondary measures included achieving and sustaining a pain-free state within 2 hours, sustained normal functioning, and the need for rescue medication.
The investigators randomized 77 subjects in this trial over an 8-month period. In both arms of the study, pain intensity decreased markedly during the first hour after analgesic administration. Changes in pain scores tended to favor prochlorperazine; however, this result did not reach statistical significance. Although pain outcomes tended to favor prochlorperazine, adverse events were less common among patients receiving metoclopramide. More than 70% of subjects in both groups stated that they would want to receive the same treatment at future ED visits for migraine.
Viewpoint
Although this study was not large enough to detect statistically significant differences between prochlorperazine and metoclopramide, it does suggest that both agents are reasonably effective. In addition, this study is likely to popularize the use of metoclopramide at a higher dose (20 mg) than is traditionally used in the ED. In fact, the authors suggested that dose-ranging studies of metoclopramide are a reasonable next step for investigators working in this area. They also suggested that it is important to incorporate patient preferences in making analgesic choices. Given the frequency of repeat ED visits for migraines, this is a highly practical recommendation. Unless there are contraindications to their use, prochlorperazine or metoclopramide should be the first-line analgesics in the ED treatment of migraines.
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