Intravenous Acetaminophen Versus Ketorolac for Prehospital Analgesia: A Retrospective Data Review

Parenteral ketorolac and intravenous (IV) acetaminophen have been used for prehospital analgesia, yet limited data exist on their comparative effectiveness.

To evaluate the comparative effectiveness of IV acetaminophen and parenteral ketorolac for analgesia in the prehospital setting.

We conducted a retrospective cross-sectional evaluation of patients receiving IV acetaminophen or parenteral ketorolac for pain management in a large suburban EMS system between 1/1/2019 and 11/30/2021. The primary outcome was change in first to last pain score. Subgroup analysis was performed on patients with traumatic pain. We used inverse probability of treatment weighting (IPTW) and propensity score matching (PSM) to estimate the treatment effect of acetaminophen versus ketorolac among all patients and the subgroup of those with traumatic pain.

Of 2178 patients included, 856 (39.3%) received IV acetaminophen and 1322 (60.7%) received parenteral ketorolac. The unadjusted mean change in pain score was -1.9 (SD 2.4) for acetaminophen group and -2.4 (SD 2.4) for ketorolac. In the propensity score analyses, there was no statistically significant difference in pain score change for the acetaminophen group versus ketorolac among all patients (mean difference, IPTW: 0.11, 95% confidence interval [CI] -0.16, 0.37; PSM: 0.15, 95% CI -0.13, 0.43) and among those with traumatic pain (unadjusted: 0.18, 95% CI -0.35, 0.72; IPTW: 0.23, 95% CI -0.25, 0.71; PSM: -0.03, 95% CI -0.61, 0.54).

We found no statistically significant difference in mean pain reduction of IV acetaminophen and parenteral ketorolac for management of acute pain.