The effectiveness of parenteral agents for pain reduction in patients with migraine presenting to emergency settings: A systematic review and network analysis

ObjectivesTo assess the comparative effectiveness and safety of parenteral agents for pain reduction in patients with acute migraine.BackgroundParenteral agents have been shown to be effective in treating acute migraine pain; however, the comparative effectiveness of different approaches is unclear.MethodsNine electronic databases and gray literature sources were searched to identify randomized clinical trials assessing parenteral agents to treat acute migraine pain in emergency settings. Two independent reviewers completed study screening, data extraction, and Cochrane risk-of-bias assessment, with differences being resolved by adjudication. The protocol of the review was registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42018100096).ResultsA total of 97 unique studies were included, with most studies reporting a high or unclear risk of bias. Monotherapy, as well as combination therapy, successfully reduced pain scores prior to discharge. They also increased the proportion of patients reporting pain relief and being pain free. Across the pain outcomes assessed, combination therapy was one of the higher ranked approaches and provided robust improvements in pain outcomes, including lowering pain scores (mean difference -3.36, 95% confidence interval [CI] -4.64 to -2.08) and increasing the proportion of patients reporting pain relief (risk ratio [RR] 2.83, 95% CI 1.74-4.61). Neuroleptics and metoclopramide also ranked high in terms of the proportion of patients reporting pain relief (neuroleptics RR 2.76, 95% CI 2.12-3.60; metoclopramide RR 2.58, 95% CI 1.90-3.49) and being pain free before emergency department discharge (neuroleptics RR 4.8, 95% CI 3.61-6.49; metoclopramide RR 4.1, 95% CI 3.02-5.44). Most parenteral agents were associated with increased adverse events, particularly combination therapy and neuroleptics.ConclusionsVarious parenteral agents were found to provide effective pain relief. Considering the consistent improvements across various outcomes, combination therapy, as well as monotherapy of either metoclopramide or neuroleptics are recommended as first-line options for managing acute migraine pain. There are risks of adverse events, especially akathisia, following treatment with these agents. We recommend that a shared decision-making model be considered to effectively identify the best treatment option based on the patient's needs. Migraine symptoms can be severe enough to cause patients to present to emergency departments for relief. In this systematic review, we attempted to identify which injectable (i.e., intravenous/subcutaneous/intramuscular) medications provide the best headache relief. We found that while most injectable medications provide adequate pain relief, patients who were given neuroleptics, metoclopramide, or a combination of two different medications reported marked and consistent improvements in migraine pain outcomes.