Randomized Clinical Trial of Intravenous (IV) Acetaminophen as an Adjunct to IV Hydromorphone for Acute Severe Pain in Emergency Department Patients

Evaluation of an Intravenous Acetaminophen Protocol in the Emergency Department

BACKGROUND

Acute pain is a leading reason for Emergency Department (ED) evaluation, accounting for nearly half of all ED visits. Therefore, providing effective non-opioid analgesics in the ED is critical. Oral acetaminophen (APAP) is commonly administered in the ED but is limited to patients tolerating oral intake. Intravenous (IV) APAP provides significant pain reduction parenterally. The purpose of this quality assessment project was to evaluate the frequency of opioid use in patients receiving IV APAP, the safety of IV APAP, and compliance with an ED IV APAP protocol.

METHODS

This study included all patients who received IV APAP in the ED of a tertiary care, level I trauma center, during a three-month period. The protocol required ED patients to be NPO (nil per os), 18 years or older, and administered with a single 1000 mg dose. The adverse reactions within 24 hours post-IV APAP, ED length of stay (LOS), and opioid administration within four hours post-IV APAP were assessed.

RESULTS

Ninety-four patients received IV APAP. All patients received a 1000 mg dose. One patient received more than one dose, but this patient had a 22-hour ED LOS. Two patients received oral medications within one hour of IV APAP (one received an antacid, and the other received carbamazepine and lamotrigine). An opioid was administered to 22 of the 94 (23.4%) patients during the four-hour protocol period. There were no reports of adverse reactions.

CONCLUSIONS

The results show excellent compliance with the protocol. IV APAP was safe and well-tolerated. Notably, most patients did not receive an opioid within four hours of IV APAP. IV APAP can be safely and effectively utilized as an analgesic and lessen ED opioid use.

Intravenous acetaminophen with morphine versus intravenous morphine alone for acute pain in the emergency room: protocol for a multicenter, randomized, placebo-controlled, double-blinded study (ADAMOPA)

BACKGROUND

In emergency medicine, pain is a frequent reason for consultation. However, there is a great variation in its management which is often insufficient. The use intravenous morphine alone or multimodal analgesia with paracetamol is recommended for severe pain. But robust data are lacking to justify the association of paracetamol with morphine versus morphine alone for pain management in the emergency room (ER). The aim of our study is therefore to assess if in patients with acute pain of moderate to severe intensity with a numerical verbal scale (NVS) ≥5 in the ER, the intravenous administration of morphine alone is not inferior to the administration of intravenous morphine combined with paracetamol at 30 min from the first administration of the study drug.

METHODS

ADAMOPA is a prospective, non-inferiority, multicenter, placebo-controlled, parallel-group, randomized (1:1), double-blind trial. Subjects will be enrolled in the ER if they experience moderate to severe, acute, non-traumatic, and traumatic pain, defined as an NVS ≥5. The primary endpoint will be the between-group difference in mean change in NVS pain scores among patients receiving the combination of intravenous morphine plus paracetamol or intravenous morphine given alone, measured from the time before administration of the study medication to 30 min later.

DISCUSSION

This trial will determine the clinical utility of the association of paracetamol with morphine for pain management in the emergency room. The ADAMOPA trial will be conducted in accordance with the International Council on Harmonization Good Clinical Practices.

TRIAL REGISTRATION

EudraCT number: 2019-002149-39.

CLINICALTRIALS

gov identifier: NCT04148495. Date of trial registration: November 1, 2019.

Intravenous acetaminophen does not reduce morphine use for pain relief in emergency department patients: A multicenter, randomized, double-blind, placebo-controlled trial

Background

Pain is one of the main reasons to present to emergency departments (EDs). Opioids are indispensable for acute pain management but are associated with side effects, misuse, and dependence. The aim of this study was to test whether a single dose of intravenous (IV) acetaminophen (paracetamol) can reduce the use of morphine for pain relief and/or morphine‐related adverse events (AEs).

Methods

ED patients >18 years with acute pain (i.e., Numeric Rating Scale [NRS] > 4) were screened for eligibility. Patients with analgesia in the past 6 h, chronic pain, or clinical instability were excluded. Patients were randomized in a 1:1 ratio to receive either morphine 0.1 mg/kg and 1 g acetaminophen IV or morphine 0.1 mg/kg and placebo IV. The intervention was double‐blinded. Additional morphine 0.05 mg/kg IV was administered every 15 minutes until pain relief (defined as NRS < 4) and whether the pain recurred. The primary outcome was the mean morphine dose for pain relief. Secondary outcomes were the total amount of morphine given, time to achieve pain relief, and AEs.

Results

A total of 220 patients were randomized and 202 evaluated for the primary outcome. The mean morphine dose for pain relief was similar in both groups (acetaminophen 0.15 mg ± 0.07 mg/kg, placebo 0.16 ± 0.07 mg/kg). There were no differences in the total amount of morphine given (acetaminophen 0.19 ± 0.09 mg/kg, placebo 0.19 ± 0.1 mg/kg), the time to achieve pain relief (acetaminophen 30 min [95% CI 17–31 min], placebo 30 min [95% CI 30–35 min]), and the frequency of AEs (overall 27.4%). Time to pain recurrence did not differ significantly between the groups (hazard ratio 1.23 [0.76–1.98], p = 0.40).

Conclusions

In ED patients, acetaminophen had no additional effect on pain control or morphine‐sparing effect at the time of first morphine administration. Titrated morphine with the algorithm used was highly effective, with 80% of all patients reporting pain relief within 60 min of starting therapy.