Low-dose methoxyflurane analgesia in adolescent patients with moderate-to-severe trauma pain: a subgroup analysis of the STOP! study
Received 25 September 2018
Accepted for publication 21 January 2019
Published 15 February 2019 Volume 2019:12 Pages 689—700
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Dr Erica Wegrzyn
Stuart Hartshorn,1 Patrick Dissmann,2 Frank Coffey,3 Mark Lomax4
1Emergency Department, Birmingham Children’s Hospital, Birmingham, UK; 2Academic Department of Emergency Medicine, James Cook University Hospital, Middlesbrough, UK; 3DREEAM: Department of Research and Education in Emergency Medicine, Acute Medicine and Major Trauma, Nottingham University Hospitals NHS Trust, Nottingham, UK; 4Data Management & Statistics, Mundipharma Research Limited, Cambridge, UK
Introduction: The undertreatment of acute pain presents a significant challenge in the Emergency Department. This post hoc subgroup analysis of a previously reported randomized controlled UK study reports the efficacy and safety of low-dose methoxyflurane analgesia in treating adolescent patients with moderate-to-severe trauma pain.
Patients and methods: Three hundred patients (96 in the adolescent subgroup) aged ≥12 years requiring analgesia for acute trauma pain (pain score of 4–7 on the Numerical Rating Scale) at triage were randomized 1:1 to methoxyflurane (up to 6 mL) or placebo (normal saline), both administered using a Penthrox® inhaler. The patient could request rescue medication (paracetamol/opioids) at any time. The primary endpoint was the change from baseline in visual analog scale (VAS) pain intensity.
Results: Mean VAS pain score for the adolescent subgroup at baseline was ~61 mm. Adjusted mean change in VAS pain intensity from baseline to 5, 10, 15, and 20 minutes was −24.5, –28.1, –31.6, and –31.7 mm for methoxyflurane and −14.6, –18.8, –19.2, and –23.7 mm for placebo, with a statistically significant treatment effect in favor of methoxyflurane overall across all four time points (–9.9 mm; 95% CI: −17.4, –2.4 mm; P=0.0104). Median time to first pain relief was significantly shorter with methoxyflurane (1 minute) than placebo (3 minutes, P<0.0001). Pain relief was reported within 1–10 inhalations in 95.7% of methoxyflurane-treated patients and 64.6% of placebo-treated patients. Rescue medication was requested by two (4.3%) methoxyflurane-treated patients and three (6.3%) placebo-treated patients. Over 95% of patients, physicians, and nurses rated methoxyflurane treatment as “Excellent”, “Very Good” or “Good” compared with between 64% and 68% for placebo. The incidence of adverse events was higher with methoxyflurane (51%) than placebo (42%), mostly comprising mild/transient dizziness and headache.
Conclusion: This subgroup analysis shows that low-dose inhaled methoxyflurane is a rapid-acting and effective analgesic in adolescent patients presenting with moderate-to-severe trauma pain.
Trial registration: Clinicaltrials.gov identifier: NCT01420159, EudraCT number: 2011-000338-12.
Keywords: acute pain, analgesic, emergency department, injury, pediatric, Penthrox
This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms.Download Article [PDF] View Full Text [HTML][Machine readable]