Examining the Effect of Intramuscular versus Intravenous Metoclopramide for Treatment of Acute Headaches to Expedite Throughput in the Emergency Department

Abstract

Background: Numerous therapies exist for both prophylactic and abortive treatments of migraine headache symptoms. Although many of these treatments are nonspecific to migraine headache, they show sufficient evidence and have garnered significant medical professional consensus for off-label use to treat acute migraine headache. One antiemetic known to be particularly effective in ceasing migraine headache symptoms is metoclopramide.

Objective: The purpose of this study is to examine the difference between intramuscular (i.m.) vs. intravenous (i.v.) metoclopramide on emergency department (ED) length of stay (LOS) and pain relief in patients presenting with presumed migraine headache. As a secondary outcome, we also assess the efficacy in treating subjective pain between these groups.

Methods: This was a single-center, retrospective study of adult ED patients presenting between January 2020 and September 2022 with a principal diagnosis of acute migraine or nonspecific headache and receiving i.m. or i.v. metoclopramide during their visit. Propensity matching was utilized to balance covariates between the i.m. and i.v. groups and adjust for confounding factors, including adjuvant therapies.

Results: LOS was decreased when i.m. metoclopramide was utilized as opposed to i.v. metoclopramide, both prior to and after propensity matching. Prior to propensity score matching, patients who received i.m. metoclopramide had a median LOS of 67 min (interquartile range [IQR] 42.50, 99.50), and patients with i.v. administration had a median LOS of 168 min (IQR 137, 234) (median difference = 102, 95% confidence interval [CI] 93-112, r = 0.44, p < 0.001). After propensity matching, median LOS for i.m. administration was 73 min (IQR 47, 103) and i.v. administration was 166 min (IQR 129, 259) (median difference = 97, 95% CI 81-144, r = 0.68, p < 0.001). A 95% CI was utilized for all outcomes. There was no significant difference in pain reduction between the two groups.

Conclusion: Intramuscular administration of metoclopramide for the treatment of acute headache in the ED is associated with a decreased median LOS compared with i.v. administration with similar clinical efficacy.

Keywords: ED throughput; Reglan; acute headache; acute migraine; i.m.; i.v.; intramuscular; intravenous; length of stay; metoclopramide; route of administration.