Postherpetic neuralgia (PHN) is the most common complication of herpes zoster (HZ) and represents a major clinical challenge due to its chronicity and impact on quality of life. Current treatments for acute HZ pain have limited efficacy in preventing PHN, highlighting the need for effective preventive strategies targeting early pathophysiological mechanisms. Venlafaxine as a plausible and clinically relevant candidate for early intervention to prevent the transition from acute HZ pain to PHN.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
832
Venlafaxine will be initiated at 75 mg once daily and titrated based on pain response and tolerability before 90 days after rash onset. All participants will receive standardized analgesic management following the World Health Organization pain ladder. In addition, the group will contain conventional treatment for HZ, including NSAIDs, opioids, antiviral drugs and so on. After 90 days from rash onset, treatment will be standardized across both groups. Participants who develop persistent pain consistent with PHN will receive guideline-based management, including gabapentinoids, tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and topical agents such as lidocaine or capsaicin, as clinically indicated.
The control group will receive conventional therapy alone before 90 days after rash onset. After 90 days from rash onset, treatment will be standardized across both groups. Participants who develop persistent pain consistent with PHN will receive guideline-based management, including gabapentinoids, tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and topical agents such as lidocaine or capsaicin, as clinically indicated.
Beijing Tiantan Hospital, Beijing, Beijing 100070
Beijing, China
RECRUITINGIncidence of PHN
PHN will be defined as persistent pain in the affected dermatome at 90 days after rash onset that is clinically meaningful, operationalized as an average pain score ≥ 3 on the NRS.
Time frame: at 90 days after rash onset
The average daily pain intensity
The numeric rating scale (NRS) score is a way to quantify the degree of subjective feelings such as pain using numbers. Generally, 0 represents no pain, and 10 represents the most severe pain. A higher score indicates more severe pain.
Time frame: at weeks 1, 2, 4, 8, 12, 24, and 52
The worst numeric rating scale score
The numeric rating scale (NRS) score is a way to quantify the degree of subjective feelings such as pain using numbers. Generally, 0 represents no pain, and 10 represents the most severe pain. A higher score indicates more severe pain.
Time frame: at weeks 1, 2, 4, 8, 12, 24, and 52
Proportion of Patients Achieving Pain Reduction
The proportion of patients achieving a ≥ 50% and ≥ 30% reduction in mean baseline pain intensity
Time frame: at weeks 1, 2, 4, 8, 12, 24, and 52
Average weekly consumption of each analgesic class
Time frame: at weeks 4, 8, 12, 24, and 52
Herpes Zoster Severity of Illness Index
The HZSOI is a severity-by-duration measure of overall pain burden associated with HZ and is typically calculated as the area under the curve of the worst pain scores over a defined period after rash onset.
Time frame: at weeks 1, 2, 4, 8 and 12
The 12-item Short-Form Health Survey (SF-12) score
The SF-12 score assesses the health-related quality of life, capturing preferences across various health states. It assesses 8 dimensions: physical functioning, physical role limitations due to physical health, bodily pain, general health, vitality, social functioning, emotional role limitations due to emotional problems, and mental health. Scores range from 0 to 100 for each dimension, with higher scores indicating better health status.
Time frame: at weeks 4, 8, 12, 24, and 52
The Medical Outcomes Study Sleep Scale (MOS)
The MOS is a questionnaire comprising 12 items that assess various aspects of sleep using a 6-point ordinal scale (1 indicating permanence and 6 indicating absence).
Time frame: at weeks 4, 8, 12, 24, and 52
Neuropathic Pain Scale
Neuropathic pain characteristics will be assessed using the Neuropathic Pain Scale in participants with developing PHN. The Neuropathic Pain Scale consists of 10 numeric rating items, each scored from 0 to 10, with higher scores indicating greater neuropathic pain severity. The scale assesses pain intensity, unpleasantness, and 8 specific pain qualities, including sharp, hot, dull, cold, sensitive, itchy, deep, and surface pain.
Time frame: at or after 90 days following rash onset
Adverse events
The incidence and proportion of adverse events will be recorded and categorized as mild, moderate, severe, or life-threatening. AEs are defined as events that arise during treatment, were absent before treatment, or worsen relative to the pretreatment state.
Time frame: Through study completion, an average of 52 weeks
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