Western Journal of Emergency Medicine: Integrating Emergency Care with Population Health

Abstract

Introduction: Headaches represent over 3 million Emergency Department visits per year comprising 2.4 percent of all ED visits. Headaches are thought to be one of the three most common complaints of patient presentations to EDs across the country. There are many proposed methods and clinical guidelines of treating acute headache presentations however data on intravenous acetaminophen usage in these settings are lacking.

Objectives: The study attempts to determine the efficacy of IV Acetaminophen as an adjunct to a standard therapy for the treatment of patients who present to the emergency department with a chief complaint of “headache” or variants thereof.

Design: Randomized, double-blind, placebo-controlled trial. Institutional IRB approval was obtained prior to implementation.

Setting: Academic Community Hospital.

Patients: Key elements of eligibility included adults ages 18-65 who had no mental or physical hindrances to pain assessment or to receiving acetaminophen. Exclusion criteria included those who had received total cumulative dose of acetaminophen >2600mg within past 24 hours, documented or suspected pregnancy, dementia, psychosis, liver cirrhosis, hemodynamic instability or other medical conditions prohibiting acetaminophen use. Ability to understand informed consent was necessary.

Interventions: All patients received prochlorperazine, diphenhydramine, 1000ml 0.9% normal saline IV, and were randomized to receive either parenteral acetaminophen (1000mg/100ml) or 100ml of 0.9% NS as control in the placebo group.

Main outcome measures: Subjective pain scores rated on a 1-10  Visual Assessment Scale were assessed repeatedly at 30 minute intervals. Length of stay and time to disposition were also noted. The incidence of rescue medications required outside of the initial regimen was also noted, with particular attention to narcotic utilization.

Results: Of the (n=45) patients who received IV acetaminophen, 36 reported a statistically significant decrease by pain score of 2 or greater from presentation at the 90 minute mark. Of the (n=45) patients who received placebo, 25 reported a statistically significant decrease by pain score reporting from presentation at the 90 minute mark. (p 0.01,  >95% CI).  For the acetaminophen group the initial mean VAS pain score was 8.7, for the placebo group 8.6. At 90 minutes 2.2 for Acetaminophen, 4.0 for placebo group. (p<0.01, >99% CI). Length of stay was decreased a mean 36.6 minutes in the Acetaminophen group. 17 patients in the IV acetaminophen and 24 patients in the placebo group received rescue medications, with 18% less in the acetaminophen group requiring narcotics (p 0.01, CI >95).

Conclusion: In Emergency Department patients with acute headache, IV Acetaminophen when used as an adjunct to prochlorperazine and diphenhydramine resulted in increased pain reduction, decreased length of stay and less rescue medications utilized including narcotics when compared to treatment with prochlorperazine and diphenhydramine alone.