Delayed Initiation of Supplemental Pain
Management is Associated with Postherpetic
Neuralgia: A Retrospective Study
Authors: Yan Min 
Published: March 2021

Background: Acute pain is a risk factor for developing postherpetic neuralgia (PHN), the most
common complication of herpes zoster (HZ). Supplemental analgesics are frequently used in the
treatment of acute herpetic pain. However, there are insufficient data regarding when to begin
supplemental analgesics, and it is unknown whether the delayed use of supplemental analgesics
increases the risk of PHN in high-risk patients.
Objectives: This study aimed to evaluate the association between initial time of supplemental pain
management and the risk of PHN in high-risk patients.
Study Design: Retrospective study.
Setting: The Department of Anesthesiology and Pain Medicine, Second Affiliated Hospital, Zhejiang
University School of Medicine.
Methods: We performed a retrospective study between May 13, 2017 and August 8, 2018 in our
clinic. Multivariable logistic regression analysis was conducted to examine the independent factors
associated with PHN. Supplemental pain management was defined as any use of opioids, tricyclic
antidepressants, or nerve blocks. A subgroup analysis was conducted in patients who received
supplemental pain management within the first 30 days of onset. According to the initial time of
supplemental pain management, patients were divided into 2 groups: the early treatment group
(≤ 14 days), and the late treatment group (> 14 days). The clinical outcomes in these 2 groups was
compared for propensity score (PS) matching.
Results: A total of 134 patients with HZ aged 50 years or older with moderate to severe pain were
enrolled in this study. The delayed initiation of supplemental pain management (> 14 days) (odds
ratio, 4.11; 95% confidence interval, 1.69-9.92; P = 0.002) and severity of rash (odds ratio, 2.93;
95% confidence interval, 1.22-7.01; P = 0.016) were independent factors associated with PHN. In
the subgroup analysis, after PS matching, there were no significant differences in the baseline clinical
parameters between the early and late treatment groups. The incidence of PHN was significantly
lower in the early treatment group than the late treatment group (36. 4% vs. 72.7%; P = 0.015).
Reduction in pain was also greater in the early treatment group.
Limitations: The findings identified in the present study are specific to the patients who were
relatively older and with moderate to severe pain. It is impossible to determine from our study
whether younger individuals and individuals with mild acute pain will benefit from early supplemental
treatments. Furthermore, because of the retrospective nature of the study, there may be some
confounders that could not be controlled. Further prospective studies with larger sample sizes and
longer follow-up periods are needed.
Conclusions: The early use of supplemental pain management may decrease the risk of PHN. It
might therefore be beneficial to consider administering supplemental pain management earlier in
older patients with moderate to severe acute herpetic pain.
Key words: Herpes zoster, postherpetic neuralgia, analgesia, opioid, nerve block, tricyclic
antidepressant