Comparison of penthrox (methoxyflurane) inhalation and intravenous morphine for acute limb fracture pain management in the emergency department: a randomized controlled trial

Objective: Effective pain management is crucial in emergency settings, and both penthrox (methoxyflurane) inhalation and intravenous morphine are commonly used analgesics. This study aimed to compare the analgesic efficacy, adverse effects, and patient satisfaction associated with penthrox spray and morphine for acute limb fracture pain management in the emergency department. Methods: This prospective, double-blinded, randomized controlled trial included 50 patients aged 20-55 years with acute limb fracture pain, randomly assigned to receive either penthrox spray or intravenous morphine. The primary outcome was pain intensity assessed using the visual analog scale (VAS) over 60 minutes. Secondary outcomes included adverse effects, vital signs, and patient satisfaction. Results: Both groups experienced significant pain relief over time, with a similar reduction in VAS scores (P<0.001). However, the penthrox spray group showed a trend toward more rapid pain reduction, although not statistically significant. The frequency of vomiting and nausea tended to be lower in the penthrox spray group (24% vs. 40%, P=0.225). There were no significant differences in patient satisfaction scores between groups. While both groups experienced a decrease in blood pressure, the heart rate remained stable in the penthrox spray group but decreased significantly in the morphine group (P<0.001). Conclusion: Penthrox spray and intravenous morphine demonstrated comparable analgesic efficacy for acute limb fracture pain in the emergency department. Penthrox sprays trended toward faster pain relief and potentially lower risk of vomiting and nausea. The stable heart rate observed with penthrox may be advantageous in certain clinical scenarios. Consideration of factors such as onset of action, adverse effects, and patient preferences may guide the choice between these analgesics.