AUTHOR=Yiping Sun , Jiayi Shen , Guang Hei , Yun Ji , Bingjie Ma , Xuehua Huang , Zhiyuan Yu , Pingchuan Ma , Ke Ma 

TITLE=The efficacy and safety of epidural morphine/hydromorphone in the treatment of intractable postherpetic neuralgia: A single-center, double-blinded, randomized controlled, prospective, and non-inferiority study

JOURNAL=Frontiers in Pharmacology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2022.1051357

DOI=10.3389/fphar.2022.1051357

ISSN=1663-9812

ABSTRACT=Objective: Postherpetic neuralgia (PHN) is a clinical puzzle, especially when patients who still suffered from moderate and severe pain after standard treatment, this single-center, double-blinded, randomized controlled, prospective and noninferiority study observed the safety and effectiveness of the epidural application of morphine or hydromorphone, trying to provide an alternative method for those patients with refractory PHN.

Methods: Eighty PHN patients with Visual analogue scale (VAS) still greater than 50mm after routine management were randomly divided into two groups according to 1:1 respectively. One group received epidural morphine (EMO group) and the other group received epidural hydromorphone (EHM group). VAS 、the number of breakthrough pain、Quality of life (QOL), anxiety/depression assessment (GAD-7 and PHQ-9 scores) were observed before treatment, at the 1, 3, 7, 14, 21, 28, 60, and 90 days after treatment, as well as side-effect. Opioid withdrawal symptoms (OWS) was also measured from 3days to 28days after treatment.
Results: EMH group was non-inferior to EMO in terms of the VDRB after one week’s treatment. The VAS of the two groups on all days after treatment was significantly lower compared to the corresponding baseline findings (P < 0.05). The breakthrough pain (BTP) decreased significantly after treatment and lasted until 14 days after treatment (P < 0.05). There was no significant difference in BTP between the two groups at each time point (P > 0.05).  In terms of the QOL, GAD-7, and PHQ-9 outcomes, those were significantly improved after treatment (P < 0.05), and there was no difference between 2 groups (P > 0.05).  
No significant AE difference across the two groups was observed in this study. Few reports of OWS were found in this trial and no significant differences between the two groups (P>0.05),

Conclusion: EMH was non-inferior to EMO in terms of the VAS decrease relative to baseline（VDRB） after one week’s treatment. For patients with VAS still greater than 50mm after standard treatment, short-term application of EMO and EHM can ameliorate intractable pain, improve the quality of life, and have no obvious side effects. Short-term epidural opioids application will not lead to the appearance of OWS.