PROCESS Trial: Effect of Duloxetine Premedication for Postherpetic Neuralgia Within 72 Hours of Herpes Zoster Reactivation-A Randomized Controlled Trial

BACKGROUND

Postherpetic neuralgia (PHN) is the most common chronic complication of herpes zoster (HZ) and results in severe refractory neuropathic pain. This study aimed at evaluating the efficacy of premedication with duloxetine in the prevention of PHN.

METHODS

The PROCESS trial is a multicenter, randomized, open-label, blinded-endpoint trial used a 1:1 duloxetine:control ratio. Adults 50 years or older with HZ who presented with vesicles within 72 hours were recruited. The primary outcome was the incidence of PHN at 12 weeks. PHN was defined as any pain intensity score other than 0 mm on the visual analog scale (VAS) at week 12 after the onset of the rash. The secondary outcomes were the number of participants with VAS >0 and VAS ≥3. The modified intention-to-treat (mITT) principle and per-protocol (PP) principle were used for the primary outcome analysis.

RESULTS

A total of 375 participants were randomly assigned to the duloxetine group and 375 were assigned to the control group. There was no significant difference in the incidence of PHN in the duloxetine group compared with the control group in the mITT analysis (86 [22.9%] of 375 vs 108 [28.8%] of 375; P = .067). PP analysis produced similar results. However, there were significant differences between the 2 groups in the number of participants with VAS >0 and VAS ≥3 (P < .05 for all comparisons).

CONCLUSIONS

Although absolute prevention of PHN does not occur, this trial found that premedication with duloxetine can reduce pain associated with HZ, and therefore can have clinically relevant benefits. Clinical Trials Registration. Clinicaltrials.gov, NCT04313335. Registered on 18 March 2020.

Thoracic paravertebral nerve block combined with acupuncture for the treatment of postherpetic neuralgia in the chest and abdomen: A prospective randomized controlled trial

BACKGROUND

Postherpetic neuralgia (PHN) is the most common complication of varicella-zoster infection and tends to occur in older people. All patients treated with a single regimen have not achieved consistent success across all current study protocols, and multimodal combination regimens still need to be explored.

METHODS

A total of 111 patients with PHN were randomly divided into drug group (group A), thoracic paravertebral nerve block group (group B), thoracic paravertebral nerve block combined with acupuncture group (group C), with 37 cases in each group. Group A: received oral gabapentin capsules and external lidocaine gel plaster; group B: combined with thoracic paravertebral nerve block based on group A; group C: combined with acupuncture based on group B. The primary outcome was effective rate, and secondary outcomes included pain sensation score (numerical rating scale), SF-36 quality of life score, and sleep quality.

RESULTS

Before treatment, there were no significant differences in numerical rating scale value, SF-36 quality of life score, and sleep quality level among the 3 groups (P > .05). After 12 weeks of treatment, the total effective rate of treatment of patients in group C (91.43%) was higher than that in group B (77.14%), and significantly higher than that in group A (51.43%) (P < .05).

CONCLUSION

Based on drug treatment combined with thoracic paravertebral nerve block and acupuncture, the treatment of PHN in the elderly can quickly and effectively relieve pain, improve the quality of life of patients, and improve the quality of sleep.

Efficacy of Paravertebral Injection of Interferon-α2b Combined with High-Voltage, Long-Term Pulsed Radiofrequency in DRG in Mitigation of Postherpetic Neuralgia: A Retrospective Study

OBJECTIVE

This investigation aims to evaluate the effectiveness of the paravertebral injection of recombinant human interferon-α2b in conjunction with high-voltage, long-term, pulsed radiofrequency (PRF) in the dorsal root ganglion for the mitigation of postherpetic neuralgia (PHN).

METHODS

This retrospective study included 84 individuals with acute PHN. The participants were divided into 3 groups. Group H was treated with interferon-α2b combined with high-voltage long-term PRF. Group C was treated with a combination of high-voltage, long-term PRF and a paravertebral injection (without recombinant human interferon-α2b), and group I was treated with interferon-α2b only. All the patients in the 3 groups were orally administered a 5-mg morphine hydrochloride quick-release tablet when a burst of pain occurred during treatment. The numerical rating scale for pain score, the interleukin-6 and galectin-3 levels, and the incidence of PHN were documented before and after therapy.

RESULTS

The pain intensity of all individuals decreased after therapy. Compared with group C, the numerical rating scale scores for group H were significantly reduced at 4, 8, and 12 weeks following therapy, and the PHN incidence was significantly lower. Compared with prior treatment, the recommended dosage of gabapentin capsules and immediate-release morphine hydrochloride tablets was reduced for group H. Compared with group C, the requirement for orally administrated gabapentin capsules and morphine hydrochloride tablets in group H was reduced significantly after treatment. No serious adverse reactions occurred in any of the 3 groups.

CONCLUSIONS

Within the context of treatment of acute PHN, the injection of interferon-α2b in conjunction with high-voltage, long-term application of PRF is more effective than PRF or the injection of interferon-α2b alone.

Combined effect of Neurotropin® and methylcobalamin on postherpetic neuralgia in mice infected with herpes simplex virus type-1

BACKGROUND

Postherpetic pain (PHP) is difficult to control. Although Neurotropin® (NTP) and methylcobalamin (MCB) are often prescribed to treat the pain, the efficacy of combined treatment for PHP remains imcompletely understood.

OBJECTIVE

In this study, we investigate the combined effects of NTP and MCB on PHP in mice.

METHODS

NTP and MCB were administered from day 10-29 after herpes simplex virus type-1 (HSV-1) infection. The pain-related responses were evaluated using a paint brush. The expression of neuropathy-related factor (ATF3) and nerve repair factors (GAP-43 and SPRR1A) in the dorsal root ganglion (DRG) and neurons in the skin were evaluated by immunohistochemical staining. Nerve growth factor (NGF) and neurotrophin-3 (NT3) mRNA expression levels were evaluated using real-time PCR.

RESULTS

Repeated treatment with NTP and MCB after the acute phase inhibited PHP. Combined treatment with these drugs inhibited PHP at an earlier stage than either treatment alone. In the DRG of HSV-1-infected mice, MCB, but not NTP, decreased the number of cells expressing ATF3 and increased the number of cells expressing GAP-43- and SPRR1A. In addition, MCB, but not NTP, also increased and recovered non-myelinated neurons decreased in the lesional skin. NTP increased the mRNA levels of NTF3 in keratinocytes, while MCB increased that of NGF in Schwann cells.

CONCLUSION

These results suggest that combined treatment with NTP and MCB is useful for the treatment of PHP. The combined effect may be attributed to the different analgesic mechanisms of these drugs.

Compounded Pain Formulations: What is the Evidence?

Pain syndromes are among the most widespread, costly, and debilitating of all neurological disorders. The number of patients living with chronic pain is expected to increase with the aging population and with the rise in obesity and diabetes across the nation. This type of pain is often insensitive to the traditional pain pharmacopeia or surgical intervention. Over the last 10 years the number of prescriptions that have been compounded by pharmacists has increased dramatically. There are a number of drugs in the area of pain management that have been formulated and compounded by pharmacists to treat conditions such as diabetic neuropathy, fibromyalgia, postherpetic neuralgia, joint pain, arthritis, and a variety of other conditions. A significant portion of these compounded analgesic preparations is made up of topical/transdermal dosage forms such as gels and creams. While the efficacy and doses of these drugs in systemic dosage forms have been widely established, little is known about the permeation and efficacy of these compounds from topical/transdermal gels. This review will provide an overview of chronic pain as a disease, the mechanisms of chronic pain, current treatment approaches to chronic pain, and a discussion of the drugs that are typically compounded into these topical formulations and studied in clinical trials.

Acupoint application for postherpetic neuralgia with qi stagnation and blood stasis and its effect on related inflammatory factors and 5-HT

OBJECTIVES

To observe the clinical efficacy of acupoint application in treating postherpetic neuralgia(PHN) with qi stagnation and blood stasis, and its effects on serum inflammatory factors and 5-hydroxytryptamine (5-HT) in patients.

METHODS

A total of 136 PHN patients were randomly divided into an observation group (68 cases, 6 case dropped out) and a control group (68 cases, 5 cases dropped out). In the observation group, the combination of swelling-reducing and pain-relieving patches and acupoint application with herbal powder was used at bilateral Sanyinjiao (SP 6), Shenque (CV 8) and ashi points. Sanyinjiao (SP 6) was applied for 30 min per session, once every 7 days; and Shenque (CV 8) and ashi points were applied for 6-8 h per session, once every 1 day. In the control group, mecobalamin injection was administered at Jiaji (EX-B 2) corresponding to the neural segments governing the painful area, 1 mL per injection, once a day. Each treatment course consisted of 7 days, 4 treatment courses were required in both groups. The visual analog scale (VAS) score for pain, 36-item short form health survey (SF-36) score, traditional Chinese medicine syndrome score, and the serum levels of inflammatory factors (monocyte chemoattractant protein-1 [MCP-1], interleukin-6 [IL-6], tumor necrosis factor-alpha [TNF-α]) and 5-HT were compared in the patients of the two groups before and after treatment, and the clinical efficacy was evaluated.

RESULTS

After treatment, the VAS scores, traditional Chinese medicine syndrome scores, serum MCP-1, IL-6, TNF-α, and 5-HT levels were decreased compared with those before treatment in both groups (P<0.05), and the results in the observation group were lower than those in the control group (P<0.05). The SF-36 scores were increased compared with those before treatment in the two groups (P<0.05), and the result in the observation group was higher than that in the control group (P<0.05). The total effective rate of the observation group was 74.2% (46/62), which was higher than 52.4% (33/63, P<0.05) of the control group.

CONCLUSIONS

The combination of swelling-reducing and pain-relieving patches and acupoint application with herbal powder has shown better efficacy in treating PHN with qi stagnation and blood stasis, which can significantly alleviate patients symptoms, improve their quality of life, and reduce serum levels of MCP-1, IL-6, TNF-α, and 5-HT.

Acupoint herbal patching for postherpetic neuralgia: A systematic review and meta-analysis

BACKGROUND

This study aimed to systematically evaluate the clinical effectiveness and safety of acupoint herbal patching in the treatment of postherpetic neuralgia.

METHODS

Eight databases including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Wan-Fang Database, China Biomedical Literature Service System, and Chongqing VIP Chinese Science were searched. The search time was set to October 2023. Two researchers independently screened the literature according to the inclusion and exclusion criteria; extracted the basic information, acupoints, Chinese herbal medicine, pain score, sleep score, depression score, and other information of the subjects, and independently assessed the risk of bias by 2 researchers. Meta-analysis of the included studies was performed using the StataMP 16 software.

RESULTS

Fifteen studies with 1362 participants were included in this meta-analysis. Ashi is the acupoint frequency at the forefront, and Borneol is the Chinese herbal medicine frequency at the forefront. The acupoint herbal patching group showed significant improvements in visual analog score (SMD: -2.09; 95% Cl: -2.77, -1.42; P < .001), sleep score (SMD: -1.58; 95% Cl: -2.11, -1.05; P < .001), depression score (SMD: -1.61; 95% Cl: -2.22, -0.99; P < .001), Chinese medicine syndrome score (SMD: -2.32; 95% Cl: -2.84, -1.80; P = .06), dermatology life quality index (weighted mean differences: -4.11; 95% Cl: -4.58, -3.63; P = .98), and related laboratory indicators compared to the control group, and the total effective rate was significantly higher (relative risk: 1.20; 95% confidence interval: 1.15, 1.26; P = .99) than the control group. Two studies reported adverse reactions, but the 2 groups were not statistically significant.

CONCLUSIONS

Acupoint herbal patching intervention in postherpetic neuralgia is effective in improving the pain, sleep, anxiety, depression, quality of life of patients, and related laboratory indicators.

[Electrical dorsal root ganglion stimulation (DRGS) for the treatment of refractory postherpetic neuralgia]

Postherpetic neuralgia (PHN) is a rare complication of herpes zoster characterized by prolonged and excruciating pain. Traditional treatments for PHN, such as analgesics, anticonvulsants and antidepressants, do not always bring the desired result. One promising alternative that is attracting the attention of the scientific community is dorsal root ganglion stimulation (DRGS). This method focuses on targeted and precise targeting of the source of pain, providing a new level of effectiveness in the treatment of PHN.

OBJECTIVE

A retrospective analysis of the technique and results of implantation of a permanent device for stimulating the spinal ganglia in patients with refractory PHN at the Burdenko Neurosurgical Center.

MATERIAL AND METHODS

The study was conducted in 7 patients (5 men, 2 women) with refractory PHN in the period from 2018 to 2020. The age of the patients ranged from 57 to 84 years (average age 74±8.4). All patients were implanted with Boston systems (Precision or Spectra versions). Stimulation parameters: pulse width - 120-210 μs, frequency - 30-130 Hz, amplitude at the lower limit of the appearance of paresthesia with the possibility of increasing with increased pain up to 5 mA. The position of the electrode depended on the location of the pain. All systems were implanted under X-ray guidance.

RESULTS

The duration of follow-up observation was more than 2.5 years. The average pain intensity one year after treatment was 3.42±2.45 points on the visual analogue scale (VAS) (a 62.3% decrease in intensity compared to baseline). In 3 (42.8%) patients, the result was characterized by us as «excellent» (intensity according to VAS decreased by 75% or more), in 1 (14.2%) - as «good» (intensity according to VAS decreased by 50-74%), in 1 (14.2%) - as «moderate» (VAS intensity decreased by 25-49% and in 2 (28.5%) as «unsatisfactory» (VAS intensity decreased by less than 25%, or postoperative complications occurred).

CONCLUSION

Given the complicated nature of PHN, the use of dorsal ganglion stimulation appears to be a promising and innovative treatment approach. Further research is needed to introduce this technique into clinical practice for the treatment of patients suffering from PHN.

Medication Management of Neuropathic Pain Disorders

It is important for Oral and Maxillofacial Surgeons to be familiar with the various neuropathic facial pain disorders and their appropriate treatments. Neuropathic pain can be characterized by the nature of the pain experienced by patients; episodic or continuous. Episodic neuropathic pain disorders include trigeminal neuralgia and glossopharyngeal neuralgia. Continuous neuropathic pain disorders compromise of disorders such as idiopathic trigeminal neuralgia, postherpetic neuralgia, central post-stroke pain, and complex regional pain syndrome. Various forms of pharmacologic management exist for these neuropathic pain disorders.

[Efficacy and safety of pulsed radiofrequency combined with gabapentin in the treatment of acute herpetic neuralgia]

Objective: To explore the clinical efficacy and safety of pulsed radiofrequency (PRF) combined with gabapentin in the treatment of acute herpetic neuralgia (AHN). Methods: A total of 123 AHN patients were retrospectively selected in Henan Provincial People's Hospital from November 2019 to July 2022, who were divided into two groups based on treatment methods: control group (treated with gabapentin, n=61) and study group (treated with gabapentin and PRF, n=62). The visual analog scale (VAS) was utilized for pain severity assessment and the self-rating scale for sleep (SRSS) was utilized for sleep quality evaluation. The differences in serum levels of interleukin (IL)-10, chemokine ligand 10 (CXCL-10), prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), IL-2 and IL-6 before and after treatment were compared between the two groups. The overall treatment effectiveness and the occurrence rates of postherpetic neuralgia and adverse reactions were evaluated in both groups. Results: Among the study group patients, 28 were male and 34 were female, and the age was (62.8±8.5) years. Among the control group patients, 35 were male and 26 were female, and the age was (64.0±7.8) years. The VAS scores of the study group before and after treatment were 7.96±1.33 and 1.52±0.60, respectively, while the control group were 7.68±1.52 and 2.70±0.64. The SRSS scores before and after treatment in the study group were 31.74±5.90 and 12.06±2.81, respectively, while those in the control group were 33.10±5.54 and 14.14±2.96, respectively. Before treatment, there were no statistically differences of the VAS scores and SRSS scores in both groups (all P>0.05). After treatment, the VAS scores and SRSS scores in both groups decreased compared with before treatment (all P<0.05), the study group's VAS scores and SRSS scores were lower than those in the control group (all P<0.05). Before treatment, there were no statistically differences of the serum levels of IL-10, CXCL-10, PGE2, COX-2, IL-2 and IL-6 in both groups (all P>0.05). After treatment, the serum levels of IL-10, CXCL-10, PGE2, COX-2 and IL-6 in both groups decreased compared with before treatment, while the IL-2 level increased. Additionally, the study group had lower serum levels of IL-10, PGE2, COX-2 and IL-6 compared with the control group (all P<0.05). After treatment, the study group had 35 cases of cure, 26 cases of effectiveness, and 1 case of ineffectiveness, while the control group had 22 cases of cure, 31 cases of effectiveness, and 8 cases of ineffectiveness. The overall treatment efficacy of the study group was better than that of the control group (P=0.012). The incidence of postherpetic neuralgia in the study group after treatment was 16.1% (10/62), which was lower than that in the control group, which was 37.7% (23/61) (P<0.05). There were no statistically differences of the occurrence rates of adverse reactions in both groups (all P>0.05). Conclusion: Combining PRF with gabapentin for the treatment of AHN demonstrates better overall efficacy and safety, which can more effectively alleviate pain, improve sleep, and reduce inflammatory cytokine levels.

Corticosteroids for preventing postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is a common, serious, painful complication of herpes zoster. Corticosteroids have anti-inflammatory properties, and might be beneficial. This is an update of a review first published in 2008, and previously updated in 2013.

OBJECTIVES

To assess the effects (benefits and harms) of corticosteroids in preventing postherpetic neuralgia.

SEARCH METHODS

We updated the searches for randomised controlled trials (RCTs) of corticosteroids for preventing postherpetic neuralgia in the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, two other databases, and two trials registers (June 2022). We also reviewed the bibliographies of identified trials, contacted authors, and approached pharmaceutical companies to identify additional published or unpublished data.

SELECTION CRITERIA

We included all RCTs involving corticosteroids given by oral, intramuscular, or intravenous routes for people of all ages, with herpes zoster of all degrees of severity within seven days after onset, compared with no treatment or placebo, but not with other treatments.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified potential articles, extracted data, assessed the risk of bias of each trial, and the certainty of the evidence. Disagreement was resolved by discussion among the co-authors. We followed standard Cochrane methodology.

MAIN RESULTS

We identified five trials with a total of 787 participants that met our inclusion criteria. No new studies were identified for this update. All were randomised, double-blind, placebo-controlled parallel-group studies. The evidence is very uncertain about the effects of corticosteroids given orally during an acute herpes zoster infection in preventing postherpetic neuralgia six months after the onset of herpes (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.45 to 1.99; 2 trials, 114 participants; very low-certainty evidence (downgraded for serious risk of bias and very serious imprecision)). The three other trials that fulfilled our inclusion criteria were not included in the meta-analysis because they did not provide separate information on the number of participants with PHN at six months. Adverse events during or within two weeks after stopping treatment were reported in all five included trials. There were no observed differences in serious (RR 1.65, 95% CI 0.51 to 5.29; 5 trials, 755 participants; very low-certainty evidence (downgraded for serious risk of bias and very serious imprecision)), or non-serious adverse events (RR 1.30, 95% CI 0.90 to 1.87; 5 trials, 755 participants; low-certainty evidence (downgraded for serious risk of bias and serious imprecision)) between the corticosteroid and placebo groups. One of these trials was at high risk of bias because of incomplete outcome data, two were at unclear risk of bias, and the other was at low risk of bias. The review was first published in 2008; no new RCTs were identified for inclusion in subsequent updates in 2010, 2013, and 2023.

AUTHORS' CONCLUSIONS

Based on the current available evidence, we are uncertain about the effects of corticosteroids given orally during an acute herpes zoster infection on preventing postherpetic neuralgia. Corticosteroids given orally or intramuscularly may result in little to no difference in the risk of adverse events in people with acute herpes zoster. Some researchers have recommended using corticosteroids to relieve the zoster-associated pain in the acute phase of the disease. If further research is designed to evaluate the efficacy of corticosteroids for herpes zoster, long-term follow-up should be included to observe their effect on the transition from acute pain to postherpetic neuralgia. Future trials should include measurements of function and quality of life, as well as updated measures of pain.

Cutaneous nerve fiber and peripheral Nav1.7 assessment in a large cohort of patients with postherpetic neuralgia

ABSTRACT

The mechanisms of pain in postherpetic neuralgia (PHN) are still unclear, with some studies showing loss of cutaneous sensory nerve fibers that seemed to correlate with pain level. We report results of skin biopsies and correlations with baseline pain scores, mechanical hyperalgesia, and the Neuropathic Pain Symptom Inventory (NPSI) in 294 patients who participated in a clinical trial of TV-45070, a topical semiselective sodium 1.7 channel (Nav1.7) blocker. Intraepidermal nerve fibers and subepidermal Nav1.7 immunolabeled fibers were quantified in skin punch biopsies from the area of maximal PHN pain, as well as from the contralateral, homologous (mirror image) region. Across the entire study population, a 20% reduction in nerve fibers on the PHN-affected side compared with that in the contralateral side was noted; however, the reduction was much higher in older individuals, approaching 40% in those aged 70 years or older. There was a decrease in contralateral fiber counts as well, also noted in prior biopsy studies, the mechanism of which is not fully clear. Nav1.7-positive immunolabeling was present in approximately one-third of subepidermal nerve fibers and did not differ on the PHN-affected vs contralateral sides. Using cluster analysis, 2 groups could be identified, with the first cluster showing higher baseline pain, higher NPSI scores for squeezing and cold-induced pain, higher nerve fiber density, and higher Nav1.7 expression. While Nav1.7 varies from patient to patient, it does not seem to be a key pathophysiological driver of PHN pain. Individual differences in Nav1.7 expression, however, may determine the intensity and sensory aspects of pain.

The effectiveness of the erector spinae plane block using methylprednisolone and bupivacaine in post-herpetic neuralgia: Case series

Post-herpetic neuralgia (PHN) is the most common chronic complication of herpes zoster and the most common pain syndrome associated with infections. There are medical and interventional treatment options in PHN, and some patients may be resistant to the preferred medical treatments. This situation negatively affects the quality of life of the patient. Interventional treatments come to the fore, especially in patients in whom medical treatments are not sufficient, and systemic side effects such as hepatotoxicity and nephrotoxicity occur. Erector spinal plane block (ESPB) is a recently described ultrasound-guided regional anesthesia technique. It is especially used to prevent post-operative pain due to trunk surgeries. In this study, ESPB was administered with methylprednisolone and bupivacaine in five patients who developed PHN after thoracic herpes zoster and did not have an expected response to three-month medical treatments. Pain severity was assessed using the Numerical Pain Rating Scale. We want to emphasize that ESPB, which is applied with steroids and anesthetics, is a speedy and longacting treatment option that increases the quality of life of the patient, has low side effects, and is a cost-effective treatment option.

Role of autophagy in the pathogenesis and regulation of pain

Pain is a ubiquitous and highly concerned clinical symptom, usually caused by peripheral or central nervous injury, tissue damage, or other diseases. The long-term existence of pain can seriously affect daily physical function and quality of life and produce great torture on the physiological and psychological levels. However, the complex pathogenesis of pain involving molecular mechanisms and signaling pathways has not been fully elucidated, and managing pain remains highly challenging. As a result, finding new targets to pursue effective and long-term pain treatment strategies is required and urgent. Autophagy is an intracellular degradation and recycling process that maintains tissue homeostasis and energy supply, which can be cytoprotective and is vital in maintaining neural plasticity and proper nervous system function. Much evidence has shown that autophagy dysregulation is linked to the emergence of neuropathic pain, such as postherpetic neuralgia and cancer-related pain. Autophagy has also been connected to pain caused by osteoarthritis and lumbar disc degeneration. It is worth noting that in recent years, studies on traditional Chinese medicine have also proved that several traditional Chinese medicine monomers involve autophagy in the mechanism of pain relief. Therefore, autophagy can serve as a potential regulatory target to provide new ideas and inspiration for pain management.

Investigational Drugs for the Treatment of Postherpetic Neuralgia: Systematic Review of Randomized Controlled Trials

The pharmacological treatment of postherpetic neuralgia (PHN) is unsatisfactory, and there is a clinical need for new approaches. Several drugs under advanced clinical development are addressed in this review. A systematic literature search was conducted in three electronic databases (Medline, Web of Science, Scopus) and in the ClinicalTrials.gov register from 1 January 2016 to 1 June 2023 to identify Phase II, III and IV clinical trials evaluating drugs for the treatment of PHN. A total of 18 clinical trials were selected evaluating 15 molecules with pharmacological actions on nine different molecular targets: Angiotensin Type 2 Receptor (AT2R) antagonism (olodanrigan), Voltage-Gated Calcium Channel (VGCC) α2δ subunit inhibition (crisugabalin, mirogabalin and pregabalin), Voltage-Gated Sodium Channel (VGSC) blockade (funapide and lidocaine), Cyclooxygenase-1 (COX-1) inhibition (TRK-700), Adaptor-Associated Kinase 1 (AAK1) inhibition (LX9211), Lanthionine Synthetase C-Like Protein (LANCL) activation (LAT8881), N-Methyl-D-Aspartate (NMDA) receptor antagonism (esketamine), mu opioid receptor agonism (tramadol, oxycodone and hydromorphone) and Nerve Growth Factor (NGF) inhibition (fulranumab). In brief, there are several drugs in advanced clinical development for treating PHN with some of them reporting promising results. AT2R antagonism, AAK1 inhibition, LANCL activation and NGF inhibition are considered first-in-class analgesics. Hopefully, these trials will result in a better clinical management of PHN.

Effect of antivirals plus low-dose, short-term glucocorticoids on post-herpetic neuralgia

BACKGROUND

Post-herpetic neuralgia (PHN) is the most common complication of herpes zoster (HZ). It is unclear whether short-term and low-dose glucocorticoids combined with antivirals can reduce the incidence of PHN.

OBJECTIVES

To investigate the effects of antivirals plus low-dose, short-term glucocorticoids on PHN.

MATERIALS & METHODS

A total of 394 patients with HZ were divided into glucocorticoid and non-glucocorticoid groups, and the incidence of PHN was studied retrospectively. Forty patients with HZ were randomized into the glucocorticoid (n=20) and non-glucocorticoid (n=20) groups. The levels of protein 100-B (S100B) and neuron-specific enolase (NSE) in the blood and the viral load in the skin lesions were measured before and after seven days of treatment. Patient condition and pain were assessed using the HZ and visual analogue scale pain scores.

RESULTS

The incidence of PHN in the glucocorticoid and non-glucocorticoid groups was 20.89% and 30.51%, respectively. In patients with onset time >seven days before treatment, the incidence of PHN was 19.81% and 40.16%, respectively. In the glucocorticoid group, after treatment, the mean serum NSE level of the glucocorticoid group decreased from 15.8 ng/mL to 14.0 ng/mL, while the mean serum S100B level decreased from 1486.3 ng/mL to 1453.7 ng/mL. There was no intergroup difference in the reduction rate of viral load. The mean condition score and pain score were significantly lower in the glucocorticoid group.

CONCLUSION

Antiviral therapy plus low-dose, short-term glucocorticoids can improve the condition of patients with HZ and partly reduce the incidence of PHN.

Effect of extracorporeal shock wave combined with pregabalin on patients with post-herpetic neuralgia

Post-herpetic neuralgia (PHN) is a chronic pain that is difficult to treat and lasts a long time, which poses a threat to patients' physical and mental health (MH) and quality of life. To analyze the effectiveness of extracorporeal shock wave (ESW) combined with pregabalin on PHN and its impact on PHN patients' quality of life with the help of a random number table. Totally 164 PHN patients were assigned to a control group (n = 82) or an observation group (n = 82). The observation group was given pregabalin combined with ESW treatment, while the control group was only given pregabalin. In the 2 groups, the general clinical data of the patients were compared. The inflammation levels including erythrocyte sedimentation rate (ESR), CRP, lymphocyte count and albumin level in both groups were compared prior to and following therapy. In addition, the difference between pretreatment and post-treatment in the 2 groups was compared with respect to neuralgia and quality of life. After treatment, the observation group exhibited much lower ESR and CRP but quite higher lymphocyte count and albumin level relative to the control group (P < .05). Additionally, the improvement in visual analogue scale (VAS) scores and short form 36 (SF-36) scale scores including role-emotional (RE), MH, physical function (PF), general health (GH), bodily pain (BP), social function (SF), vitality (VT), and role-physical (RP) scores in the 2 groups were pronounced following treatment, which was more apparent in the observation group (P < .05). The combination of ESW with pregabalin can reduce the inflammation, improve the quality of life of PHN patients and effectively relieve their neuralgia.

Clinical efficacy of LED golden light combined with acyclovir in the treatment of herpes zoster: a single-center prospective study

This study aimed to explore the safety and clinical efficacy of light emitting diode (LED) golden light combined with acyclovir in treating herpes zoster (HZ). According to the random number table, 54 inpatients with HZ were divided into control group, golden-light group, and red-light group, with 18 cases in each group. The control group received acyclovir intravenous drip, while the patients in the red-light group received acyclovir intravenous drip and red-light LED phototherapy, and the golden-light group received acyclovir intravenous drip and golden-light LED phototherapy. Primary assessments included herpes stopping time, incrustation time, decrustation time, pain visual analog scale scores (VAS), and incidence of postherpetic neuralgia (PHN) on the 30th and 90th days. Golden-light group and red-light group showed a shorter herpes stopping time, incrustation time, and decrustation time (P < 0.05) compared to the control group (P < 0.05), while the golden-light group showed a shorter incrustation time and decrustation time than the red light group (all P < 0.05). After treatment VAS scores, the golden-light group showed a significant improvement compared to the control group. The golden-light group showed a better PHN incidence than the control group at 30 days follow-up. Compared with the comprehensive curative effect, the total effective rates of the golden-light group, red-light group, and control group were 88.89%, 77.78%, and 72.22%, respectively, and the efficacy of the golden-light group was better than that of the control group and red-light group. Golden light combined with acyclovir can shorten the course of HZ, relieve pain, and reduce the occurrence of PHN, and the effect is better than that of the red-light group and the control group.

Diagnosis and treatment of varicella-zoster virus infection with herpetic visceral neuralgia without rash: A case report

RATIONALE

Herpes zoster (HZ) is an infection caused by the varicella-zoster virus reactivation, often leading to peripheral nervous system infection and pain. This case report aimed to present 2 patients with damaged sensory nerves originating from the visceral neurons of the lateral horn of the spinal cord.

PATIENT CONCERNS

Two patients presented intractable, severe lower back pain and abdominal pain, but without rash or herpes. A female patient was admitted 2 months after symptom onset. She was presented with paroxysmal, acupuncture-like pain in the right upper quadrant and around the umbilicus without apparent incentives. A male patient was presented with recurrent episodes of paroxysmal and spastic colic in the left waist and left middle abdomen for 3 days. Abdominal examination showed no tumors or organic lesions in their intra-abdominal tissues or organs.

DIAGNOSES

After excluding organic lesions on the waist and in abdominal organs, patients were diagnosed with herpetic visceral neuralgia without rash.

INTERVENTION

The treatment for herpes zoster neuralgia or postherpetic neuralgia was applied for 3 to 4 weeks.

OUTCOME

Antibacterial and anti-inflammatory analgesics were not effective in either patient. The therapeutic effects of herpes zoster neuralgia or postherpetic neuralgia treatment were satisfactory.

LESSONS

Herpetic visceral neuralgia can be easily misdiagnosed due to the absence of a rash or herpes, resulting in delayed treatment. When patients have severe, intractable pain but no rash or herpes, and the biochemical and imaging examinations are normal, the treatment method for HZ neuralgia can be used. If the treatment is effective, HZ neuralgia is diagnosed. If not, shingles neuralgia can be ruled out. Further investigations are required to elucidate the mechanisms of pathophysiological changes in varicella-zoster virus-induced peripheral HZ neuralgia or visceral neuralgia without herpes.

A meta-epidemiological study on the reported treatment effect of pregabalin in neuropathic pain trials over time

BACKGROUND

Pregabalin is a drug used to treat neuropathic pain, and its use has increased substantially since 2007. Early trials found a strong treatment effect on pain for post-herpetic neuralgia and diabetic neuropathy. However more recent studies have failed to replicate these results.

METHODS

This meta-epidemiological study aimed to assess change in the reported effectiveness of pregabalin in neuropathic pain trials over time, and if a change is present, determine any associated factors.

DATA SOURCES

We performed electronic searches for published trials in Medline, Embase and Cochrane Central Register of Controlled Trials databases; and unpublished trials on ClinicalTrials.gov, the EU Clinical Trials Register, and the Australia New Zealand Clinical Trials Registry with no restrictions.

STUDY SELECTION

We included randomized, placebo-controlled trials of pregabalin for treatment of neuropathic pain in adults.

DATA EXTRACTION AND SYNTHESIS

Two authors independently extracted study data: sample size and mean baseline, end-point and change in pain scores with measures of variance, trial end year, publication year, clinical indication, funding source, country of study, treatment duration, treatment dose, mean age and percentage male.

PRIMARY OUTCOME MEASURE

We defined treatment effect as the mean difference in pain scores between pregabalin and placebo groups at trial end-point and assessed for change over time using a random-effects meta-regression, adjusted for sample size, indication, treatment duration (weeks) and treatment dose.

RESULTS

We included 38 randomized published trials (9038 participants) and found that between 2003 and 2020, the reported treatment effect of pregabalin decreased by 0.4 points (95% CI: 0.3 to 0.6; p<0.001) on an 11-point pain scale per 5-year interval, from 1.3 points (95% CI: 1.0 to 1.5) in trials conducted in 2001-2005, to 0.3 (95% CI: -0.1 to 0.7) in trials conducted in 2016-2020. The reported treatment effect was lower than the minimal clinically important difference (MCID) of 1.7 points across all time periods, doses and most indications and was not found to be associated with study characteristics.

CONCLUSIONS

The reported treatment effect or analgesic efficacy of pregabalin from clinical trials has diminished over time. Clinical recommendations may need to be re-evaluated to account for recent evidence and to consider whether pregabalin therapy is indicated.

Oral herbal medicine for treatment of postherpetic neuralgia: A protocol for systematic review and meta-analysis

BACKGROUND

Postherpetic neuralgia (PHN) is the most common complication of shingling. Herbal medicine for PHN is clinically used to improve chronic pain and other symptoms that reduce the quality of life (QoL), such as sleep disturbances and emotional problems. This study aims to describe methods for synthesizing evidence for the effectiveness and safety of herbal medicine for treating PHN.

METHODS

Randomized controlled trials using herbal medicine in patients with PHN will be included in this review. Electronic databases such as MEDLINE via PubMed, EMBASE, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, China National Knowledge Infrastructure, WanFang, KoreaMed, Research Information Service System, Korean Studies Information Service System, Database Periodical Information Academic, Oriental Medicine Advanced Searching Integrated System, and Korea Citation Index will be searched without language limitations from their inception to September 2022. Two authors will perform quality assessments independently using the Cochrane risk-of-bias tool. The primary outcome will be pain intensity, and the secondary outcomes will be global impression, anxiety, depression, sleep disturbance, QoL, and safety. All data from eligible studies will be synthesized for meta-analysis.

RESULTS

This study will be a systematic review and meta-analysis to evaluate the effectiveness and safety of oral herbal medicine for treatment of PHN.

CONCLUSION

This study will provide evidence for herbal medicine as a potential treatment for PHN which is advantageous not only for patients but also for researchers and policymakers.

Painful diabetic peripheral neuropathy: real-world comparison between topical treatment with lidocaine 700 mg medicated plaster and oral treatments

INTRODUCTION

Painful diabetic peripheral neuropathy (PDPN), a common complication of diabetes mellitus, is challenging to treat. Efficacy and tolerability of the topical lidocaine 700 mg medicated plaster (LMP) and well-established first-line oral medications (OM) were compared in refractory PDPN patients.

RESEARCH DESIGN AND METHODS

This is a subgroup analysis of a non-interventional, retrospective 24-week cohort study using anonymized routine medical care data from the German Pain eRegistry. Propensity score matching provided 732 datasets per treatment group. Primary effectiveness endpoint was the absolute change in average 24-hour Pain Intensity Index (0-100 mm) from baseline after 4, 12 and 24 weeks of treatment and over the entire treatment period.

RESULTS

The majority of this multimorbid and polymedicated study population of patients with PDPN had suffered pain for more than a year and presented with a high pain burden despite a median of seven previous analgesic medications. LMP treatment resulted in significant reductions in pain intensity and improvements in daily functioning already after 4 treatment weeks. Effectiveness was maintained over the treatment period even when concomitant analgesics were reduced or discontinued and quality of life improved. Mean change in the primary effectiveness parameter over the 24-week treatment period was -30.2 mm (SE 0.38) and -17.0 mm (SE 0.51) in the LMP and OM groups, respectively. Improvements in all effectiveness parameters were significantly greater under LMP than under OM treatment (p&lt;0.001). Significantly fewer patients under LMP than OM experienced drug-related adverse events (DRAEs; 9.6% vs 61.6%, p&lt;0.001) and discontinued treatment due to DRAEs (4.4% vs 35.8%, p&lt;0.001).

CONCLUSIONS

LMP was effective and well tolerated in routine clinical care of patients with PDPN. The more favorable benefit/risk profile and greater reduction in intake of concomitant analgesics compared with OM suggest LMP as a useful treatment option for PDPN.

TRIAL REGISTRATION NUMBER

EUPAS 32826.

Ultrasound-Guided Erector Spinae Block Versus Ultrasound-Guided Thoracic Paravertebral Block for Pain Relief in Patients With Acute Thoracic Herpes Zoster: A Randomized Controlled Trial

BACKGROUND

Severe acute pain is a significant risk factor for postherpetic neuralgia (PHN). The importance of early management in alleviating zoster pain cannot be overstated.

OBJECTIVES

This study aimed to determine the efficiency and safety of one bolus injection thoracic paravertebral block (PVB) and erector spinae plane block (ESB) in individuals with acute thoracic herpes zoster (HZ) in preventing PHN.

STUDY DESIGN

A prospective randomized controlled trial.

SETTING

Tanta University Hospitals, Tanta, Egypt.

METHODS

Ninety participants over the age of 50 years with chest wall herpetic eruption, lasting shorter than a week along with moderate to severe pain, who got adequate antiviral medication. Patients were chosen at random and classified into 3 equal groups. Group C (control group) did not receive any intervention. Group ESB received US-guided ESB with 25 mg bupivacaine 0.5%, plus 8 mg dexamethasone (10 mL volume). Group PVB received US-guided PVB with 25 mg bupivacaine 0.5%, plus 8 mg dexamethasone (10 mL volume).

RESULTS

Numerical rating scale (NRS) showed insignificant differences at baseline. NRS for pain at 1, 3, 4, 12, and 24 weeks was significantly reduced in group ESB compared to group C and in group PVB than group C and insignificantly different between group ESB and group PVB. Doses of pregabalin and acetaminophen were comparable at 1 week among the studied groups. Doses of pregabalin and acetaminophen at 3, 4, 12, and 24 weeks were significantly lesser in group ESB compared to group C and in group PVB than group C and insignificantly different between group ESB and group PVB. After 3 months, the incidence of persistent herpetic pain was not significantly different between the study groups. After 6 months, the incidence of persistent herpetic pain was statistically significantly lower in groups ESB and PVB than in group C (P = 0.037 and 0.015, respectively) without significant difference between group ESB and group PVB.

LIMITATIONS

Small sample size, single center study.

CONCLUSIONS

Both ESB and PVB were effective in controlling acute pain and persistent herpetic pain after 6 months (which was evident by lower NRS for pain and doses of pregabalin and acetaminophen), but ESB is safer (no reported pneumothorax and hypotension).

Phenotypes and Genotypes in Postherpetic Neuralgia Drug Therapy: A Narrative Mini-review

Neuropathic pain is a debilitating symptom reported by patients presenting with postherpetic neuralgia (PHN). Efforts to alleviate this pain have been projected to lie in individualization of pharmacological treatment through pain phenotyping and subsequent investigations into the genetic basis of PHN therapy. Understanding the various mechanisms related to these phenotypes can aid in improvement of available treatment options and discovery of new ones. Knowledge and application of genetic variations in PHN, structural proteins, and genes can aid in ascertaining risk, susceptibility to, severity of, and protection from PHN. This review summarizes the most recent information that has been published on phenotypes and genotypes with possible clinical applications and directions for future research.

The Effect of Erector Spinae Plane Block With and Without Addition of Magnesium on Relief of Pain from Post-herpetic Neuralgia

BACKGROUND

The best tool for management of postherpetic neuralgia (PHN) is a matter of debate. The use of ultrasound-guided erector spinae plane block (ESPB) in patients with PHN may decrease pain severity and the need for analgesics.

OBJECTIVES

The objective of this clinical study was to test the efficacy of ESPB with and without the addition of magnesium sulphate on pain control and analgesic consumption in patients with PHN.

STUDY DESIGN

Randomized controlled double-blinded trial.

SETTING

A single university center.

METHODS

A total of 75 patients with PHN were included in the study. Patients were randomly divided into 3 equal groups. Group A received sham ESPB (2 mL normal saline), Group B received ESPB with 20 mL of bupivacaine (0.25%), and Group C received ESPB with 20 mL of bupivacaine (0.25%) and 100 mg magnesium sulphate. All patients received standard medical care. The pain score, the consumption of pregabalin and acetaminophen, the incidence of complications, and the patient's satisfaction were measured and recorded.

RESULTS

In comparison to the control group, the use of real ESPB with or without the addition of magnesium significantly decreased the Numeric Rating Scale score for pain during the first week of follow-up (P < 0.05); decreased the mean daily consumption of pregabalin and acetaminophen from the third to the twelfth week of follow-up (P < 0.05); and increased the level of patients' satisfaction (P = 0.03). The addition of magnesium sulphate showed an insignificant difference in comparison to the use of bupivacaine alone in ESPB (P ? 0.05).

LIMITATIONS

The study was limited by being a singlecenter study, using a single-level injection, and using a single volume of local anesthetic mixture.

CONCLUSION

ESPB with or without adding magnesium sulphate is an effective pain management tool for cases of PHN. It leads to a significant decrease in pain score and analgesic requirements.

Comparison of lidocaine and ropivacaine stellate ganglion blockade in treating upper limb postherpetic neuralgia

To provide a basis for treating postherpetic neuralgia (PHN), we compared the efficacy of lidocaine and ropivacaine stellate ganglion block (SGB) in PHN treatment in the upper limbs.Data from 252 patients with upper-limb PHN were retrospectively analyzed. The lidocaine group (n = 118) was treated with oral pregabalin capsules 75 mg twice a day, tramadol hydrochloride sustained release tablets 100 mg twice a day, and amitriptyline 25 mg once at night combined with ultrasound-guided lidocaine SGB; the ropivacaine group (n = 134) was orally administered the same medicines combined with ultrasound-guided ropivacaine SGB. The visual analog scale (VAS), self-rating anxiety scale (SAS), and adverse reactions were compared between the groups before treatment and at 1 week, 1 month, and 3 months after treatment.There were no significant differences between the lidocaine and ropivacaine groups in terms of sex, age, height, weight, and pain duration (P > .05). There was no significant difference between the groups in VAS and SAS scores before treatment (P > .05). At 1 week, 1 month, and 3 months after ultrasound-guided SGB treatment, the VAS and SAS scores were significantly lower in the ropivacaine group than in the lidocaine group (P < .05). There were no significant differences between the groups in terms of adverse reactions (P > .05).For ultrasound-guided SGB treatment of upper limb PHN, ropivacaine is superior to lidocaine. Ultrasound-guided ropivacaine SGB is safe and effective for the treatment of upper limb PHN.

Changing the paradigm in postherpetic neuralgia treatment: lidocaine 700 mg medicated plaster

OBJECTIVE

Chronic pain is currently considered a disease state with biopsychosocial consequences and a negative impact on patients' quality of life (QoL). Pain from postherpetic neuralgia (PHN) can persist for months or years and is a prototypical example of chronic pain. We analyzed PHN as a model of chronic pain, including its effects on QoL and clinical aspects. We explored treatment options, focusing on the topical treatment with lidocaine 700 mg medicated plaster (LMP) and how this impacts PHN management.

MATERIALS AND METHODS

This article is a narrative review of published studies. Preclinical and clinical studies were retrieved from literature through a search performed in PubMed/MEDLINE.

RESULTS

To choose the appropriate treatment for chronic pains, such as PHN, not only efficacy but also tolerability, manageability, practicality, and compliance are important factors, especially in the long term. It is also important to set treatment expectations with the patients as total suppression of pain may be unrealistic, and a balance needs to be found between pain control and the minimization of adverse events. In this respect, LMP may be the best currently available treatment: it is easy to use, has low systemic absorption and thus a low risk for pharmacological interactions. Therefore, treatments can be personalized, and concomitant medications can be added, if needed. Recent data from a real-world study support this view by showing that LMP has superior effectiveness in reducing pain and improving the QoL compared to other commonly used systemic treatments and confirming its good tolerability profile that is mainly characterized by localized skin reactions.

CONCLUSIONS

LMP is one of the best currently available treatment options for PHN patients balancing good efficacy with an excellent tolerability profile and can therefore be considered for use as a first-line treatment for PHN.

Efficacy and Safety of a New Sustained-release Pregabalin Formulation Compared With Immediate-release Pregabalin in Patients With Peripheral Neuropathic Pain: A Randomized Noninferiority Phase 3 Trial

OBJECTIVE

This study investigated whether a new sustained-release (SR) pregabalin formulation is noninferior to immediate-release (IR) pregabalin in alleviating peripheral neuropathic pain in Korean patients.

MATERIALS AND METHODS

This was a randomized, double-blind, active-controlled phase 3 study of patients with diabetic peripheral neuropathy or postherpetic neuralgia from 41 sites in South Korea in 2017-2018. Eligible patients were randomized (1:1) to receive once-daily SR pregabalin or twice-daily IR pregabalin (150 to 600 mg/d) in a double-dummy manner for 12 weeks according to a stratified permuted block randomization scheme. The primary endpoint was the Daily Pain Rating Scale score at the end of treatment, averaged from the last 7 available scores.

RESULTS

A total of 319 of 371 (86.0%) randomized patients completed the 12-week treatment (SR pregabalin: n=154; IR pregabalin: n=165; per-protocol set: n=296). The least square mean difference between both groups for the primary endpoint was 0.06 (SE 0.19); (95% confidence interval -0.31 to 0.42), with the lower limit of the confidence interval above the pre-specified margin (-0.78; Pnoninferiority<0.0001). Drug-related treatment-emergent adverse events (TEAEs) were comparable between both groups. The incidence of drug-related TEAEs leading to treatment discontinuation was low (SR pregabalin: 2.7%; IR pregabalin: 1.1%). No serious drug-related TEAEs or deaths occurred.

DISCUSSION

The results demonstrate that the new once-daily SR pregabalin formulation is noninferior to twice-daily IR pregabalin in reducing peripheral neuropathic pain and is well tolerated in Korean patients with diabetic peripheral neuropathy or postherpetic neuralgia after 12 weeks of treatment.

Lidocaine 700 mg medicated plaster for post-herpetic neuralgia: focus on Quality of Life, effectiveness and safety - a retrospective observational study

OBJECTIVE

Postherpetic neuralgia (PHN) is a neuropathic pain syndrome following herpes zoster (HZ) infection, characterized by pain that persists for months to years after the resolution of the HZ rash. Therapeutic management remains challenging for every clinician. We report the follow-up of patients diagnosed with PHN and treated with lidocaine 700 mg medicated plaster (LMP), focusing on effectiveness, safety, and Quality of Life (QoL).

MATERIALS AND METHODS

This study is a retrospective observational investigation of patients with PHN treated with LMP. Patients were regularly followed for pain intensity, co-analgesic consumption, adverse effects, QoL using the EQ-5D, and patient satisfaction for 8 weeks.

RESULTS

A total of 31 patients were evaluated. At enrollment, 18 patients (58.1%) were treated with at least one PHN concomitant medication, for which the number and dosing remained constant during the study. Patients had a mean average pain intensity of 6.5±1.0 at baseline, which decreased to 3.6±1.1 at week 4 and 2.8±0.9 at week 8. Four patients reported erythema, and one complained of vesicles eruption associated with pruritus. EQ-5D at weeks 4 and 8 of treatment showed persisting improvements in all domains except for the "anxiety/depression" domain. At week 8, <80% of patients reported to be satisfied or very satisfied.

CONCLUSIONS

This study adds further weight to the growing body of clinical and research evidence that LMP treatment is effective and well-tolerated in patients with PHN.

Subcutaneous Peripheral Nerve Stimulation for Treatment of Acute/Subacute Herpes Zoster-related Trigeminal Neuralgia: A Retrospective Research

OBJECTIVES

The purpose of this study was to observe the effect of subcutaneous stimulation of the peripheral nerve on acute or subacute zoster occurring in trigeminal nerve branches, and to evaluate the preventive effect of prior temporary implant of a peripheral stimulation electrode in the acute or subacute phase of herpes zoster (HZ) (from 30 to 90 d after zoster onset) before postherpetic neuralgia (PHN) presents.

METHODS AND MATERIALS

A total of 26 patients' medical records were analyzed. All of patients had received temporary subcutaneous peripheral nerve stimulation (PNS). The clinical efficacy of treatment was evaluated on a visual analog scale (VAS), and dosages of pain medication were recorded before and at 1 to 6 months after the temporary stimulation. The rate of PHN was reevaluated at a 6 months follow-up.

RESULTS

There was a significant decrease in VAS values after PNS. Medication doses decreased significantly after TPNS. The rate of clinically meaningful PHN (VAS >3) dropped below 4%.

DISCUSSION

This study revealed that PNS is an effective treatment for trigeminal herpetic neuralgia following acute or subacute HZ. As a extend neuromodulation method, subcutaneous peripheral nerve-field stimulation might be a useful option to reduce the progression of neuropathic changes caused by persistent transmission of pain signals in the trigeminal nerve branches after the acute or subacute phase of HZ.

Efficacy and safety of EMA401 in peripheral neuropathic pain: results of 2 randomised, double-blind, phase 2 studies in patients with postherpetic neuralgia and painful diabetic neuropathy

ABSTRACT

The analgesic efficacy and safety of 2 phase 2b studies of EMA401 (a highly selective angiotensin II type 2 receptor antagonist) in patients with postherpetic neuralgia (EMPHENE) and painful diabetic neuropathy (EMPADINE) were reported. These were multicentre, randomised, double-blind treatment studies conducted in participants with postherpetic neuralgia or type I/II diabetes mellitus with painful distal symmetrical sensorimotor neuropathy. Participants were randomised 1:1:1 to either placebo, EMA401 25 mg, or 100 mg twice daily (b.i.d) in the EMPHENE and 1:1 to placebo or EMA401 100 mg b.i.d. in the EMPADINE. The primary outcome for both the studies was change in weekly mean of the 24-hour average pain score, using a numeric rating scale from baseline to week 12. Both the studies were prematurely terminated due to preclinical hepatotoxicity on long-term dosing, although not observed in these studies. Out of the planned participants, a total of 129/360 (EMPHENE) and 137/400 (EMPADINE) participants were enrolled. The least square mean reduction in numeric rating scale pain score was numerically in favour of EMA401 100 mg arm in both EMPHENE (treatment difference: -0.5 [95% confidence interval: -1.6 to 0.6; P value: 0.35]) and EMPADINE (treatment difference: -0.6 [95% confidence interval: -1.4 to 0.1; P value: 0.10]) at the end of week 12. However, as the studies were terminated prematurely, no firm conclusion could be drawn but the consistent clinical improvement in pain intensity reduction across these 2 studies in 2 different populations is worth noting.

Pilot Analyses of Interferon Subtype Expression Profiles in Patients with Herpes Zoster or Postherpetic Neuralgia

Postherpetic neuralgia (PHN) is a painful neuropathic complication resulting from herpes zoster (HZ). The pain manifests in peripheral nerves infected by herpesviruses, mostly from reactivation of latent varicella zoster virus. Mechanistic descriptions suggest that PHN develops because of disrupted immune system signaling and inflammation or peripheral nerve damage; however, the pathophysiology is not clear. It is difficult to predict/prevent PHN manifestations of HZ patients due to the lack of accurate diagnostics. In this study, sera from healthy controls, HZ patients, and PHN patients were subjected to an interferon (IFN) expression profile (IEP) study. The corresponding cDNAs were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) using primer pairs against a panel of 21 different IFN subtypes. The results showed that distinct IEPs were observed among HZ and PHN cohorts in comparison to the healthy controls. Together, this pilot study suggested that the IEP study may be used as a molecular tool for diagnosis of PHN and assist in designing new PHN therapeutic protocols.

Should we prescribe anticonvulsants for acute herpes zoster neuralgia and to prevent postherpetic neuralgia?: A protocol for meta-analysis and benefit-risk assessment

BACKGROUND

Herpes zoster-associated pain [i.e., acute herpes zoster neuralgia (AHN) and postherpetic neuralgia (PHN)] has the potential to cause significant patients' burden and heath resource expenditure. PHN is refractory to the existing treatments, and the consensus is preventing the transition of AHN to PHN is better than treating PHN. Anticonvulsants (e.g., gabapentin, pregabalin) have been recommended as one of the first-line therapies for PHN. In practice, anticonvulsants have also decreased the severity and duration of AHN and reduced the incidence of PHN. Nevertheless, its clinical application to AHN is hampered by inadequate evidence for its efficacy and safety. We performed this protocol for a systematic review to explore the efficacy and safety of anticonvulsants for AHN. Besides, a benefit-risk assessment of anticonvulsants for AHN would be performed to estimate the extent to which these drugs could relieve symptoms and whether the benefits outweigh harms.

METHODS

The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) was used to prepare our protocol and the results will be reported according to the PRISMA. We will search the China National Knowledge Infrastructure (CNKI), Chinese VIP Information (VIP), Cochrane Library, Embase, and PubMed databases, from inception to August 2019. Furthermore, Clinicaltrials (http://www.clinicaltrials.com) and Chinese Clinical Trial Registry (http://www.chictr.org.cn/abouten.aspx) will also be searched for relevant studies. Selection of eligible articles and data extraction will be independently performed by reviewers. We will record the characteristic information, pain outcomes, incidence of PHN and adverse effects. Data synthesis and other statistical analyses will be conducted using Review Manager Software 5.3 and STATA13.0. Furthermore, risk of bias assessment, meta-regression and subgroup analyses, publication bias assessment, grading of evidence will be performed for included studies.

ETHICS AND DISSEMINATION

As this systematic review will be performed based on published data, no ethical approval is needed. The findings will be submitted in peer-reviewed journals for publication.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019133449.

A fixed nitrous oxide/oxygen mixture as an analgesic for patients with postherpetic neuralgia: study protocol for a randomized controlled trial

BACKGROUND

The pain management of postherpetic neuralgia (PHN) remains a major challenge, with no immediate relief. Nitrous oxide/oxygen mixture has the advantages of quick analgesic effect and well-tolerated. The purpose of this study is to investigate the analgesic effect and safety of nitrous oxide/oxygen mixture in patients with PHN.

METHODS/DESIGN

This study is a single-center, two-group (1:1), randomized, placebo-controlled, double-blind clinical trial. A total of 42 patients with postherpetic neuralgia will be recruited and randomly divided into the intervention group and the control group. The control group will receive routine treatment plus oxygen, and the intervention group will receive routine treatment plus nitrous oxide/oxygen mixture. Data collectors, patients, and clinicians are all blind to the therapy. The outcomes of each group will be monitored at baseline (T0), 5 min (T1), and 15 min (T2) after the start of the therapy and at 5 min after the end of the therapy (T3). The primary outcome measure will be the pain intensity. Secondary outcomes included physiological parameters, adverse effects, patients' acceptance of analgesia, and satisfaction from patients.

DISCUSSION

Previous studies have shown that nitrous oxide/oxygen mixture can effectively relieve cancer patients with breakthrough pain. This study will explore the analgesic effect of oxide/oxygen mixture on PHN. If beneficial to patients with PHN, it will contribute to the pain management of PHN.

TRIAL REGISTRATION

Chinese Clinical Trial Register ChiCTR1900023730 . Registered on 9 June 2019.

External therapy of Chinese medicine for postherpetic neuralgia: A protocol for systematic review and meta-analysis

BACKGROUND

Postherpetic neuralgia (PHN), the most common complication of herpes zoster, brings about a health-care burden at both the individual and societal levels. External therapy of Chinese medicine (ETCM) is an effective treatment of PHN generally available in China, yet there is incomplete evidence to evaluate the efficacy and safety of it.

METHODS

This protocol is based on the previous reporting items. We will search 3 English databases (PubMed, EMBASE, and the Cochrane Library) and 3 Chinese databases (CNKI, CBM, and Wan Fang Database) until January 2020. RCTs to evaluate the efficacy and safety of external therapy of Chinese medicine for postherpetic neuralgia will be included. The primary outcome will be assessed by VAS or NRS. We will use the criteria provided by Cochrane Handbook 5.3.0 for quality evaluation and risk assessment, and use the Revman 5.3 software for meta-analysis.

ETHICS AND DISSEMINATION

Ethical approval is not required for systematic review and meta- analysis. The results of this review will be disseminated in a peer-review journal.

PROSPERO REGISTRATION NUMBER

CRD42020163511.

The Treatment of Topical Drugs for Postherpetic Neuralgia: A Network Meta-Analysis

BACKGROUND

Postherpetic neuralgia (PHN) is a neuropathic pain that causes a reduction in patients' quality of life. There are many topical drugs for PHN, including topical lidocaine patch, topical application of capsaicin, and others.

OBJECTIVES

This study aims to compare the efficacy and safety of topical drugs for PHN.

STUDY DESIGN

Relevant studies were found by systemically searching for terms including "topical" and "Postherpetic neuralgia" in PubMed, Cochrane library, MEDLINE, and EMBASE databases (inception through June 12, 2019). The primary outcome was the percentage of change in the Numeric Rating Scale or the Visual Analog Scale scores from baseline. The secondary outcome was the number of adverse events.

METHODS

The efficacy and safety of topical drugs for PHN was investigated by the pairwise meta-analysis and Bayesian network meta-analysis, applying Revman 5.3, the Stata 14.0 software, and GeMTC 0.14.3.

RESULTS

Twelve studies met the inclusion criteria, and eligible studies were selected for the ultimate meta-analysis. Our meta-analysis displayed 6 topical drugs for PHN. Lidocaine, high-concentration capsaicin, and aspirin/diethyl ether (ADE) had a higher possibility of bringing pain relief than placebo. Among them, lidocaine had the highest possibility of being the most effective drug for PHN and had the statistical significances compared with diclofenac, high-concentration capsaicin, indomethacin, low-concentration capsaicin, and placebo, and lidocaine was significantly preferable than other effective drugs in the aspect of safety.

LIMITATIONS

(1) The small number of included studies; (2) a small number of patients and short-term trials in progress, including lidocaine and ADE; (3) both randomized controlled trial and crossover randomized trial were included in our network meta-analysis; (4) only studies published in English were evaluated; (5) lack of head-to-head comparisons of some treatments; (6) different measurement methods were used in different trial, which may cause deviation; and (7) with the lack of cycles in the included trials, the inconsistency factors cannot be calculated, and node-splitting method cannot be performed in our network meta-analysis to check the inconsistency.

CONCLUSIONS

Compared with other topical drugs, lidocaine was the most effective and most tolerable drug to be recommended for PHN.

Effect of Repeated Paravertebral Injections with Local Anesthetics and Steroids on Prevention of Post-herpetic Neuralgia

BACKGROUND

The usefulness of early sympathetic blockade in the prevention of postherpetic neuralgia (PHN) has been reported. However, the optimal duration and frequency of paravertebral blocks that prevent or maximally reduce the incidence of PHN need to be clarified.

OBJECTIVES

To assess the impact of weekly separated 2 versus 3 paravertebral injections using local anesthetic and steroids, early in the course of acute thoracic herpes zoster, on the incidence of postherpetic neuralgia.

STUDY DESIGN

Randomized single-blind study.

SETTING

University hospitals.

METHODS

Eighty patients suffering from acute thoracic herpes zoster eruption were randomly allocated into 2 groups. Group I received paravertebral block using 25 mg bupivacaine plus 8 mg dexamethasone in a total volume of 10 mL twice one week apart. Group II received paravertebral block using 25 mg bupivacaine plus 8 mg dexamethasone in a total volume of 10 mL 3 times one week apart. All patients received daily 300 mg pregabalin in divided doses (150 mg/12 hours). Pain scores were evaluated during each visit. Once the patient reported mild pain, the trial for reducing the pregabalin dose was done. Acetaminophen was available as a rescue analgesia. At each assessment visit, the total analgesic consumption was recorded. The times of the complete resolution of the pain and the skin eruption were recorded. The incidence of PHN after 3, 6, and 12 months was also reported.

RESULTS

Pre-eruptive pain severity and duration were comparable between both groups. There was no statistically significant difference between both groups with respect to the day of the block, the total duration of pain until the first block, and eruptive and herpetic pain duration parameters. The severity of skin lesions was comparable among both groups. Four patients (10.5%) had PHN in group I versus 3 patients (8.1%) in group II after 3 months of follow-up. Meanwhile, these numbers were 3 patients (7.9%) and 2 patients (5.4%) at 6 and 12 months in both groups, respectively. Compared with basal parameters, effective pain control was noticed in both groups with no significant difference between groups.

LIMITATIONS

Small size, lack of complete blindness, and the use of fluoroscopy in block performance in the era of performing this block under ultrasound.

CONCLUSIONS

Repeated paravertebral blocks using local anesthetic and steroids weekly over 2 or 3 weeks in the management of acute thoracic herpes zoster can provide safe and effective pain relief and minimize the incidence of PHN. However, no added benefit was detected from repeated blocks more than twice.

Long-term safety and efficacy of mirogabalin in Asian patients with postherpetic neuralgia: Results from an open-label extension of a multicenter randomized, double-blind, placebo-controlled trial

OBJECTIVE

Postherpetic neuralgia (PHN) is a condition that results from nerve dysfunction following an episode of acute herpes zoster (shingles). Mirogabalin is a novel, selective oral α2δ ligand that demonstrated safety and efficacy in a multicenter, randomized, double-blind, placebo-controlled 14-week study in Asian patients with PHN. This 52-week, open-label extension study investigated the long-term safety and efficacy of flexible-dosage mirogabalin in Asian patients with PHN.

METHODS

This open-label extension study enrolled patients who completed the placebo-controlled study. Patients started with a dose of 5 mg mirogabalin twice daily (BID), which was followed by a flexible dose of 10 or 15 mg BID. During the study, patients assessed their pain using the Short-Form McGill Pain Questionnaire (SF-MPQ). Adverse events were monitored throughout the study.

RESULTS

Of 239 enrolled patients, 184 (77.0%) completed the study and 185 patients (77.4%) received the 15 mg BID dose most during the treatment duration. Most treatment-emergent adverse events (TEAEs) were mild or moderate. The most common TEAEs were nasopharyngitis, somnolence, dizziness, weight increased, and edema. All SF-MPQ scales decreased from baseline to week 52.

CONCLUSIONS

This study showed the safety and stable pain management of a long-term flexible dosing regimen of mirogabalin 10 or 15 mg twice daily for 52 weeks in patients with PHN. CLINICAL TRIAL REGISTERED AT CLINICALTRIALS.GOV:: NCT02318719.

SUMMARY FOR TABLE OF CONTENTS

Mirogabalin-a novel α2δ oral ligand-was shown to be effective and well tolerated for treating postherpetic neuralgia (PHN) in an Asian multicenter, randomized, double-blind, placebo-controlled, 14-week study. This open-label, 52-week study was conducted as an extension of the double-blind study to demonstrate long-term safety and efficacy of mirogabalin.

[Whether or not to use gabapentinoids in adults with chronic neuropathic pain]

CASE DESCRIPTION

A frail 85-year-old woman with chronic neuropathic pain after hip surgery, not responding to treatment with acetaminophen and morphine patches. Should she be prescribed a gabapentinoid?

DISCUSSION

Gabapentinoids and antidepressants are considered first-line therapies. They achieve clinically relevant (i.e. ≥ 50%) pain reduction in approximately one-third of patients with postherpetic neuralgia and peripheral diabetic neuropathy. Evidence for other types of neuropathic pain is limited. Adverse events occur frequently and are mostly mild in nature; serious adverse effects are rare. Prescription of gabapentinoids in specific patient groups (e.g. elderly patients and patients with a history of depression or substance abuse) deserves careful consideration, because the risk/benefit ratio in those groups may be altered. In order to reduce the risk of withdrawal symptoms, slow tapering is recommended.

CONCLUSION

Chronic neuropathic pain often has a negative impact on the quality of life and is difficult to treat. In general, treatment with a gabapentinoid is a possible first-line treatment option. However, they may be relatively contraindicated in vulnerable patients.

Caudal block with steroid in the treatment of acute voiding dysfunction and pain caused by sacral herpes zoster: A case report

RATIONALE

Herpes zoster (HZ) involving sacral dermatome is very rare, which can sometimes cause voiding dysfunction.

PATIENT CONCERNS

A 52-year-old man presented with acute pain and voiding dysfunction, following HZ in his right sacral dermatomes.

DIAGNOSES

Twenty two days before presentation HZ occurred and 9 days after the onset of the HZ, he had trouble with starting urination and weak urine stream which was managed with tamsulosin 0.4 mg orally once a day and intermittent urinary catheterization. He was treated with 150 mg of pregabalin 2 times a day, tramadol 50 mg 2 times, and acetaminophen 600 mg 2 times a day. However, his pain intensity was 5 on the numerical analogue scale (NRS) from 0 (no pain) to 10 (worst pain imaginable).

INTERVENTIONS

Fluoroscopy guided caudal block was performed with a mixture of 0.5% lidocaine 10 mL and triamcinolone 40 mg.

OUTCOMES

One day after the procedure, the pain decreased to 1 on the NRS score. In addition, voiding difficulty greatly improved. Three days after the intervention, the patient reported complete resolution of pain and voiding dysfunction. He currently remains symptom free at a 3-month follow-up.

LESSONS

A caudal block with steroid can be an effective option for treatment of acute voiding dysfunction and pain following sacral HZ.

Comparison of ropivacaine with ropivacaine and fentanyl in continuous epidural analgesia for postherpetic neuralgia: A STROBE-compliant retrospective study

Continuous epidural analgesia (CEA) using local anesthetics is frequently used to control herpes zoster pain and prevent postherpetic neuralgia (PHN). However, few studies have been conducted to determine the efficacy of epidural drugs administered as CEA to manage PHN. This retrospective study was designed to evaluate the effectiveness of CEA with ropivacaine alone or with ropivacaine and fentanyl for controlling pain caused by PHN.We reviewed the medical records of 71 patients. We studied 2 groups: epidural ropivacaine (ER; CEA with ropivacaine alone; n = 44) and epidural ropivacaine and fentanyl (Epidural ropivacaine and fentanyl (ERF); CEA with ropivacaine and fentanyl; n = 27). To evaluate pain, a numeric rating scale (NRS) was evaluated at 6 time points: immediately before the procedure (baseline NRS score); 1 hour after the procedure; 14 days after the procedure; and 1, 3, and 6 months after the procedure. Complication rates were recorded during CEA. We also investigated whether additional invasive procedures were needed due to insufficient pain control during the 6-month follow-up period.After adjusting for confounding variables, there were no significant differences in the NRS scores between the 2 groups at any time point. The adjusted odds ratio for additional invasive procedures within 6 months after CEA was 1.03-times higher in the ERF group than in the ER group, but this difference was not statistically significant (95% confidence interval: 0.33-3.23, P = .96). Rates of complication (dysuria, vomiting, nausea, itching sensation, and hypotension) during CEA were higher in the ERF group than in the ER group. However, the differences were not statistically significant.There was no difference in the management of pain in patients with PHN between the groups. Epidural administration of fentanyl with ropivacaine did not improve pain management when compared to ropivacaine alone. Although not statistically significant, the incidence of complications during CEA was higher in the opioid combination group.

Cost-effectiveness of mirogabalin for the treatment of post-herpetic neuralgia in Taiwan

Objectives: To assess the cost-effectiveness of mirogabalin versus no treatment or pregabalin in patients with post-herpetic neuralgia (PHN) from a third-party perspective in Taiwan.Methods: A Markov model, which was developed with 2-week cycles and 1-year time horizon from the Taiwanese National Health Insurance Administration perspective, consisted of three health states: "mild," "moderate," and "severe" pain. Average daily pain score (ADPS) was assessed at the end of each cycle. Patients either remained in, or transitioned from, their assigned health state to a different state according to their pain score changes. All patients entered the model in "moderate" (4 ≤ ADPS <7) or "severe" (7 ≤ ADPS ≤ 10) pain health states. Efficacy data was informed by the pivotal Phase III trial, or by a network meta-analysis (NMA). Utility values were obtained from published literature and cost data from Taiwanese clinical experts and the Taiwan National Health Insurance Administration, using 2018 New Taiwan dollar (NT$). Probabilistic analysis was conducted to test the robustness of base case results.Results: Head-to-head analysis showed mirogabalin 30 mg to be cost-effective versus placebo in PHN. The deterministic analysis estimated a quality-adjusted life years gain of 0.041 at an ICER of NT$11,231 (US$365) versus no treatment (ICER: NT$274,567 [US$8,900]). In the NMAs, mirogabalin was cost-effective compared to pregabalin 150 mg (ICER: NT$515,881 [US$16,720]) and 300 mg (ICER: NT$201,671 [US$6,535]). Mirogabalin 30 mg dominated pregabalin 600 mg. Results from sensitivity and scenario analyses confirmed these results.Conclusion: Mirogabalin 30 mg, a potent and selective α2δ ligand, is a cost-effective treatment option for PHN in Taiwan, with ICERs below the willingness-to-pay threshold.

Postherpetic Neuralgia: Current Evidence on the Topical Film-Forming Spray with Bupivacaine Hydrochloride and a Review of Available Treatment Strategies

PURPOSE OF REVIEW

This is a comprehensive review of the literature about the use of bupivacaine hydrochloride for the treatment of post-herpetic neuralgia (PHN). It briefly reviews the background, biology, diagnosis and conventional treatment for PHN, and then introduces and compares the recent evidence for the use of topical bupivacaine.

RECENT FINDINGS

PHN is defined by pain lasting 90 days or more after the initial presentation of herpes zoster ("Shingles", HZ) rash and is the most common complication of this disease. A product of re-activation of the Varicella-Zoster virus (VZV), HZ is diagnosed more than 1 million times annually in the United States. Approximately 20% of patients with HZ will experience PHN and will continue to suffer intermittent neuropathic symptoms, including itching and pain, that is sharp, stabbing, throbbing or burning, with the pain localized to the site of their original rash. This long-lasting pain compares with the severity of long-standing rheumatics and osteo-arthritis and is accompanied by severe allodynia causing significant suffering, and a financial burden that is manifested in both healthcare costs and loss of quality-adjusted life years. Prevention of PHN may be achieved with the Zoster vaccine, although there is still a large segment of unvaccinated population. Moreover, the Zoster vaccine is not always effective for prevention. Current treatment includes medical (systemic tricyclic antidepressants, anticonvulsants and opioids, topical lidocaine and capsaicin) and interventional (subcutaneous Botox injections, nerve blocks and nerve stimulation) therapies. These therapies are not always effective, and each carries their own profile of side effects and risks. Moreover, up to 50% of patients with PHN are refractory to management. Recent evidence is emerging to support the use of topical local anesthetics for the treatment of PHN. Two small studies recently found topical lidocaine spray to be effective in treating paroxysmal pain attacks associated with PHN. Bupivacaine is a longer-lasting local anesthetic, and a film-forming formulation allows easy and durable application to the affected skin. Recent studies show that topical film-forming bupivacaine is safe and as effective as lidocaine for the treatment of PHN. PHN is an important though common complication of HZ and can cause long-lasting pain and disability. Current treatment for PNH is limited by efficacy and safety profiles of individual therapies. Recent evidence points to topical local anesthetics as an effective and safe alternative to conventional therapy. Film-forming bupivacaine may offer a durable and safe option for this otherwise difficult to treat syndrome.

Delayed Initiation of Supplemental Pain Management is Associated with Postherpetic Neuralgia: A Retrospective Study

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.

Systematic review and network meta-analysis of the efficacy and safety of lidocaine 700 mg medicated plaster vs. pregabalin

Objective: Neuropathic pain prevalence is estimated between 7% and 10% of the population. International guidelines recommend a variety of drugs at different therapy lines for pain relief. However, side effect profiles, for example, prompted the UK government recently to classify pregabalin and gabapentin as class C drugs. Lidocaine 700 mg medicated plaster (LMP) might be a safer alternative. A systematic review assessed how LMP and pregabalin compared in terms of efficacy and safety. The review focused on pain reduction, quality of life and adverse events in peripheral neuropathic pain (PNP) i.e. post-herpetic neuralgia, diabetic peripheral neuropathy, post-surgical/trauma, or other PNP conditions.Methods: Electronic databases were searched as well as a number of other sources up to November 2018. Sensitive strategies were used, with no restriction by language or publication status. Two independent reviewers screened records and extracted data with consensus determining final decisions. Risk of bias was assessed using the Cochrane Collaboration 2011 checklist for RCTs. Full network meta-analysis was conducted to compare LMP to pregabalin 300/600 mg in terms of pain reduction, quality of life, as well as serious adverse events and selected adverse events. Trials with enriched enrolment design were excluded.Results: Searches retrieved 7,104 records. In total 111 references pertaining to 43 RCTs were included for data extraction. Bayesian network meta-analysis of several pain outcomes showed no clear difference in efficacy between treatments However, LMP was clearly advantageous in terms of dizziness and any adverse event vs. pregabalin 600 mg/day and discontinuations vs. pregabalin 300 mg/day or 600 mg/day, as well as being associated with improved quality of life (albeit in this case based on weak evidence).Conclusions: LMP was found to be similar to pregabalin in reducing pain in all populations but had a better adverse events profile.

Treatment Patterns and Medication Use in Patients with Postherpetic Neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is a chronic, painful condition characterized by persistent pain following resolution of a herpes zoster (HZ) infection. Epidemiologic data demonstrate that the risks for HZ infections and the development of PHN increase with age.

OBJECTIVE

To characterize prescribing patterns, health care utilization, and treatment costs for adults with PHN based on real-world data.

METHODS

This study analyzed medical and pharmacy claims from 2010 to 2014 in the MarketScan Commercial and Medicare Supplemental databases. PHN patients were identified based on criteria from a published algorithm. PHN treatment patterns were analyzed by age and reported descriptively for patients aged < 65 or ≥ 65 years. Excess incremental health care costs were calculated for PHN patients by comparing expenditures for a cohort of PHN patients to expenditures of a propensity score-matched control group of patients with HZ alone.

RESULTS

Approximately 0.4% of patients aged < 65 years were diagnosed with HZ versus 1.3% of patients aged ≥ 65 years; approximately 15.3% of HZ patients aged < 65 years and 26.4% of patients aged ≥ 65 years were diagnosed with PHN. Overall, opioids remained the most frequently prescribed initial treatment. Approximately 21.6% of PHN patients received an opioid as an initial treatment for PHN, 15.1% received gabapentin; 8.9% received a prescription nonsteroidal anti-inflammatory drug (NSAID); 8.3% received a lidocaine patch; 3.3% received pregabalin; 2.5% received a tricyclic antidepressants (TCAs); 0.8% received other topical lidocaine; and < 1% received capsaicin. Observed first-line use of the lidocaine patch and gabapentin was higher in patients aged ≥ 65 years relative to patients aged < 65 years. When separated by age group, only 24.6% of patients aged < 65 years and 38.5% of patients aged ≥ 65 years were prescribed a recommended first-line treatment for initial PHN therapy (gabapentin, lidocaine patch, pregabalin, and TCAs). Comparisons of treatment costs of PHN patients to matched HZ patients without PHN indicated that PHN patients initiated on opioids had the highest mean additional health care expenditure compared with PHN patients initiated on other medications. On average, PHN patients initiated on opioids had $7,601 additional health care expenditure compared with HZ patients with no PHN; additional expenditures were $6,428 for pregabalin, $4,213 for lidocaine patches, $3,478 for gabapentin, $3,304 for NSAIDs, and $2,797 for TCAs, respectively.

CONCLUSIONS

Management of PHN is associated with substantial utilization of opioid-based therapies across all ages. Medications supported by evidence either as first-line therapies or as part of a multimodal regimen for the management of PHN are underused relative to opioid-based PHN therapies. Improving adherence to evidence-based PHN treatment regimens offers the potential to reduce opioid prescribing first line and reduce overall treatment costs. Given the emphasis to reduce opioid prescribing to minimize the risk of dependence, abuse, and diversion, multimodal analgesic treatments that can avoid or reduce opioid use should be considered.

DISCLOSURES

Research funding was provided by SCILEX Pharmaceuticals. The sponsor reviewed and approved the research plan and provided support for manuscript preparation through Patel's role as a coauthor of this manuscript. The sponsor's product (lidocaine patch) was not used in this study. Patel is a paid employee of SCILEX Pharmaceuticals. Goss is an employee and minority owner of Boston Healthcare Associates, which received a research grant from SCILEX Pharmaceuticals to conduct this study. Gudin reports advisory board fees from AcelRx Pharmaceuticals and BioDelivery Sciences International and consulting fees from Averitas, Daiichi, Hisumitsu, Nektar, Purdue, Quest Diagnostics, SCILEX Pharmaceuticals, and US WorldMeds, unrelated to this study. Fudin reports advisory board fees from AcelRx Pharmaceuticals, Human Half-Cell, Quest Diagnostics, GlaxoSmithKline, SCILEX Pharmaceuticals, BioDelivery Sciences, Daiichi Sankyo, and Salix Pharmaceuticals; speaker fees from Daiichi Sankyo, Salix Pharmaceuticals, Abbott Laboratories, Acutis Diagnostics, and AstraZeneca; and consulting fees from Firstox Laboratories, unrelated to this study. The other authors have nothing to disclose. Parts of this research were presented at the AMCP Managed Care & Specialty Pharmacy Annual Meeting; April 22, 2016; San Francisco, CA, and at the 35th Annual Scientific Meeting of the American Pain Society; May 11-14, 2016; Austin, TX.

Comparison Of Efficacy Of Two Different Doses Of Famciclovir In The Prevention And Treatment Of Postherpetic Neuralgia

BACKGROUND

Herpes Zoster is a common dermatological ailment. Various treatment modalities are in use for prevention of Post Herpetic Neuralgia (PHN) which is the most common complication of herpes zoster. Our study aimed to compare the efficacy of famciclovir 250 mg versus 500 mg in this regard.

METHODS

The study was conducted at a tertiary care hospital recruiting subjects by using simple random sampling, group A patients received famciclovir 250 mg thrice daily for 1 week while group B patients were administered 500 mg. Follow ups were arranged at 2, 4 & 12 weeks. Efficacy was assessed by pain evaluation as per numeric rating scale and counting number of skin lesions. PHN was taken as persistent pain at 4 weeks follow up. All the statistical analysis was done using SPSS.

RESULTS

A total of 30 patients were included in the study with each group (A & B) containing 15 patients each. Both dosing groups were statistically consistent with each other in reducing pain at 2, 4 and 12 weeks follow up. Skin lesions were not observed after 2 weeks in either group. The median of difference of pain scores at 2 weeks was similar as at 4 weeks.

CONCLUSION

Famciclovir 250 mg thrice daily for one week is equally effective as 500 mg in treating active herpes zoster and prevention of PHN. However, long term follow-up is required for assessing the true incidence of PHN.