Effect of Electroacupuncture on Postherpetic Neuralgia: A Randomized Clinical Trial

Study Overview

Postherpetic neuralgia, or PHN, is a long-lasting nerve pain condition that can follow shingles. It is often described as burning, stabbing, or shooting pain that persists after the rash has healed. Because PHN can be difficult to treat and may interfere with sleep, mood, and daily activities, researchers continue to look for safer and more effective options beyond medications alone. This randomized clinical trial examined whether electroacupuncture could reduce pain in people with PHN compared with sham electroacupuncture, a placebo-like procedure designed to mimic treatment without delivering the active therapeutic effect.

Why This Trial Matters

Current treatments for PHN commonly include anticonvulsants, antidepressants, topical agents, and sometimes opioids. However, these options may provide only partial relief and can cause side effects such as dizziness, sedation, constipation, or poor tolerance in older adults. Acupuncture has been used for pain management in traditional medicine for centuries, and electroacupuncture adds a mild electrical current to the needles to potentially enhance the analgesic effect. While earlier studies suggested benefit, the quality of evidence had often been limited. This study was designed to provide stronger evidence through a multicenter, randomized, sham-controlled approach.

How the Study Was Conducted

The trial was carried out at 7 tertiary hospitals in China. Participants were enrolled from October 2020 to July 2022, with follow-up continuing through September 2022. Data analysis was performed later, from August to December 2025.

Adults aged 45 to 75 years with PHN and moderate to severe pain were eligible. Pain severity was measured using the 11-point Numeric Rating Scale, or NRS-11, where 0 means no pain and 10 means the worst imaginable pain. Participants needed a score of 4 or higher to be included.

Out of 1072 screened patients, 624 were excluded. The remaining 448 participants were randomized into 2 groups: 225 received electroacupuncture and 223 received sham electroacupuncture. In total, 383 participants completed the trial, representing an 85.49% completion rate.

What Electroacupuncture Involved

Participants received 20 treatment sessions over 4 weeks, followed by a 4-week posttreatment follow-up period. In the electroacupuncture group, needles were placed at selected acupuncture points and connected to a device that delivered a controlled electrical stimulus. In the sham group, the treatment was designed to resemble true electroacupuncture but without the active therapeutic stimulation expected to affect pain.

This design is important because it helps distinguish the true treatment effect from placebo response, expectation, and the natural fluctuation of pain over time.

Main Results

Among the 448 participants, the average age was 63.19 years, and just over half were men. At baseline, both groups had similar pain levels.

By week 4, the electroacupuncture group showed a greater reduction in pain than the sham group. The average change in NRS-11 score was -1.52 in the electroacupuncture group compared with -0.99 in the sham group. After adjustment, the mean difference was -0.53 points, with a 95% confidence interval from -0.61 to -0.43, and the result was highly statistically significant (P < .001).

The study also defined responders as patients who achieved at least a 30% reduction in pain score. The responder rate was 46.68% in the electroacupuncture group, compared with 24.28% in the sham group. The adjusted risk difference was 22.40 percentage points, with a 95% confidence interval of 13.02% to 31.79%, again with P < .001.

These findings suggest that electroacupuncture provided a real, measurable benefit beyond placebo treatment.

Durability of Benefit

The treatment effect did not disappear immediately after the sessions ended. The benefits continued through the 1-month follow-up period, suggesting that electroacupuncture may provide more than just short-term relief. For patients with PHN, this matters because persistent pain often requires treatments that can sustain improvement rather than only producing brief symptom reduction.

Safety Findings

A major concern with any pain treatment is safety, especially in older adults who may already be taking multiple medications. In this trial, no clinically significant adverse events were observed. That does not mean the procedure is completely risk-free, but it suggests that when performed in a controlled clinical setting by trained practitioners, electroacupuncture was well tolerated.

Common minor acupuncture-related effects in general practice may include temporary soreness, mild bruising, or lightheadedness, but the study did not report major safety problems.

What the Results Mean

This trial adds meaningful evidence that electroacupuncture may be a useful nonpharmacological option for PHN. The improvements were statistically significant and also clinically relevant for a portion of patients, especially given the limited treatment options for this painful condition.

It is important, however, to interpret the findings in context. The average reduction in pain score, while real, was moderate rather than dramatic. Electroacupuncture should therefore be viewed as one part of a broader PHN management plan, not necessarily a stand-alone cure. In practice, it may be most helpful when combined with standard pain medications, sleep support, skin care, physical activity as tolerated, and attention to mood and quality of life.

Possible Explanation for the Benefit

Researchers believe electroacupuncture may reduce pain through several mechanisms. It may influence the nervous system by modulating pain signaling pathways, increasing the release of endogenous opioids, and affecting inflammation and nerve sensitization. These biological effects may help calm the overactive pain response that often persists after shingles.

Although the exact mechanism is not fully understood, the growing body of research suggests that acupuncture-based therapies can interact with both peripheral and central pain networks.

Strengths and Limitations

This study had several strengths. It was randomized, controlled, multicenter, and sham-controlled, which makes the evidence more reliable than uncontrolled case series or observational reports. The sample size was relatively large for an acupuncture trial, and the follow-up period allowed investigators to see whether benefits persisted beyond the active treatment phase.

There are also limitations. The trial was conducted only in China, so results may not fully generalize to other healthcare systems or patient populations. As with many procedural therapies, blinding can be challenging, and expectations may still influence perceived improvement. In addition, while pain scores improved, the study does not prove that electroacupuncture will work equally well for every patient with PHN.

Clinical Takeaway

For patients with postherpetic neuralgia, electroacupuncture appears to offer a safe and effective option that can reduce pain severity and increase the chance of meaningful improvement. It may be especially appealing for people seeking a non-drug treatment or for those who have side effects from medication.

That said, PHN can be complex and often requires individualized care. Patients considering electroacupuncture should discuss it with their clinician, particularly if they have bleeding disorders, take anticoagulants, have skin infections, or have other medical issues that could affect procedure safety.

Conclusion

In this randomized clinical trial, electroacupuncture produced greater pain relief than sham electroacupuncture in people with postherpetic neuralgia, with benefits that persisted for at least 1 month after treatment and no clinically significant safety concerns reported. These findings support electroacupuncture as a promising complementary therapy for the integrated management of PHN.

Trial Registration

ClinicalTrials.gov Identifier: NCT04560361.