Continuous epidural infusion of local anesthetics and shorter duration of acute zoster-associated pain

Non-oral pharmacological interventions in the management of herpes zoster-related pain: a review of current research

Herpes zoster-associated pain is a difficult-to-treat pathologic pain that seriously affects patients' quality of life. In recent years, emerging therapeutic techniques such as autologous platelet-rich plasma, sympathetic nerve block and pulsed radiofrequency have been gradually applied in the field of pain with the advantages of less trauma, quicker recovery and significant efficacy. These therapeutic options have become a new hope for the treatment of herpes zoster-associated pain. This article reviews the studies on herpes zoster-associated pain in non-oral drug therapy, summarizes the efficacy, safety, and possible mechanisms, and provides a reference basis for clinical treatment.

Efficacy of intermittent epidural dexamethasone bolus for zoster-associated pain beyond the acute phase

Herpes zoster develops when latent varicella zoster virus is reactivated in the trigeminal or dorsal root ganglions. Zoster-associated pain (ZAP) is neuropathic pain caused by the herpes zoster virus. Histological studies of postherpetic neuralgia patients suggest that inflammation is involved in ZAP. The effectiveness of local anesthetic and steroid epidural injections in ZAP patients has been reported. However, most studies included patients with acute herpes zoster, and the safety and therapeutic effects of different doses of epidural steroids in ZAP patients remain elusive. In this study, we randomly assigned 42 patients with severe ZAP beyond the acute phase, as determined by a numeric rating scale (NRS) score ≥7, to receive continuous epidural infusion of local anesthetics with either a one-time 5-mg dose or intermittent repeated doses (15 mg total) of dexamethasone. We found that intermittent repeated epidural dexamethasone bolus resulted in reduced NRS scores and an increased likelihood of complete remission in ZAP patients without any adverse effects. Thus, our results suggest that intermittent repeated epidural dexamethasone administration is safe and effective for treatment of ZAP beyond the acute phase.

Effectiveness of continuous epidural analgesia on acute herpes zoster and postherpetic neuralgia: A retrospective study

Despite early treatment of herpes zoster (HZ), postherpetic neuralgia (PHN) can persist. This study was designed to compare the therapeutic and pain relief effects of continuous epidural analgesia (CEA) on the chronic phase as well as the acute phase of HZ with standard medical treatment.Medical records of 227 patients with moderate to severe zoster-associated pain that had not responded to standard medications were retrospectively reviewed. Patients received standard treatment alone (medical group) or standard treatment plus concurrent CEA (epidural group). The acute and chronic groups were classified according to a 4-week cut-off with regard to time between the onset of the rash and the first treatment. Four groups were studied: Group A (acute/medical group); Group B (acute/epidural group); Group C (chronic/medical group); and Group D (chronic/epidural group). Pain was assessed using the visual analog scale (VAS) and measured every 2 weeks for 6 months. We compared the pain rating at 6 months after the first treatment with the initial pain rating. Response to treatment was defined as a ≥50% reduction in pain severity since the initial visit. Remission was considered complete for patients whose VAS pain score was ≤2 for >3 successive visits and who no longer needed medical support.Patients who received a combination of standard treatment plus CEA (Groups B and D) had significantly higher response to treatment (P = .001) than patients receiving standard treatment alone (Groups A and C). The adjusted odds ratio (OR) for response to treatment in the epidural group versus the medical group was 5.17 (95% confidence interval [CI]: 1.75-15.23) in the acute group and 5.37 (95% CI: 1.62-17.79) in the chronic groups. The adjusted OR for complete remission in the epidural group versus the medical group was 3.05 (95% CI: 1.20-7.73) in the acute group and 4.46 (95% CI: 1.20-16.54) in the chronic group.CEA can effectively relieve pain caused by PHN and acute HZ and increase remission rates. Combining CEA with standard medical treatment may offer a clinical advantage in the management of pain caused by PHN as well as acute HZ.

Treatment of herpes zoster with ultrasound-guided superficial cervical plexus block

Herpes zoster most commonly occurs in elderly patients, and usually affects sensory neurons. Therefore, its characteristic symptoms are segmental pain, itching, and sensory changes in the affected areas. A 71-yr-old woman experienced painful herpetic rash on the right cervical 2-4 dermatomes for 16 days. Two days after the onset of the rash, she was diagnosed with herpes zoster, and prescribed 250 mg famciclovir three times a day for 7 days, pregabalin 150 mg twice a day, and tramadol 150 mg once a day for 14 days, by a dermatologist. Despite medication, her pain was rated at an intensity of 6/10 on the numeric rating scale. In addition, she complained of severe itching sensation on the affected dermatomes. Superficial cervical plexus block (SCPB) was performed at the right C4 level with 15 ml 0.5% lidocaine plus triamcinolone 30 mg. Five days after the procedure, pain and itching completely disappeared. SCPB may be an effective option for the treatment of acute pain and itching arising from herpes zoster, and for the prevention of postherpetic neuralgia.

Factors contributing to pain chronicity

The chronicity of pain is the feature of pain that is least understood and most directly linked with our inability to effectively manage pain. Acute pain is relatively responsive to our current pharmacologic and interventional armamentarium. However, as pain persists, our ability to treat effectively diminishes and the patient's frustration and resource utilization increases. This article explores our current understanding of the factors linked to pain duration and the transition from acute to chronic pain in both human and animal models, and across a spectrum of human chronic pain conditions.

Herpes zoster and postherpetic neuralgia: optimizing management in the elderly patient

Herpes zoster (HZ) results from reactivation of varicella-zoster virus (VZV) that has been persistent and clinically dormant in spinal ganglia or cranial sensory nerves since primary infection with VZV. The most common reason for reactivation is a decline in zoster-specific cell mediated immunity as a result of aging (immunosenescence). More than two-thirds of HZ cases occur in people >or=60 years of age. HZ incidence is higher in persons who are immunocompromised as a result of disease (e.g. malignancies such as lymphoma, HIV/AIDS, diabetes mellitus) or treatments such as chemotherapy and radiotherapy. HZ incidence is also increased by therapeutic immune suppression following organ transplantation and in patients taking high-dose corticosteroids. However, HZ may occur in otherwise healthy young people. Although serious and life-threatening complications sometimes occur, the most common complication is postherpetic neuralgia (PHN), which may persist for months or years and is significantly resistant to treatment despite substantial advances in the understanding of its pathological mechanisms. The medical and social costs of HZ and PHN are high, particularly in older patients. Prevention of PHN in patients with HZ is unsatisfactory although antiviral drugs reduce the duration of pain after HZ. A live attenuated vaccine has been shown to reduce the incidence of HZ and PHN as well as the burden of illness in subjects aged >or=60 years. In view of the increasing numbers of elderly persons in the population and the poor outcomes of PHN treatment, vaccination against HZ at approximately 60 years of age appears to be an appropriate strategy.

Treatment of postherpetic neuralgia

Postherpetic neuralgia (PHN) remains one of the most troublesome common chronic neuropathic pain conditions. Many controlled trials have been published showing good efficacy and reasonable tolerability. These include gabapentinoids, opioids, tricyclic antidepressants, and topical lidocaine and capsaicin. Combination therapies are possible, but have not been proven, and long-term follow-up is limited. Only few case series exist for surgical and other invasive therapies and their role remains uncertain.

Optimum pain relief with continuous epidural infusion of local anesthetics shortens the duration of zoster-associated pain

OBJECTIVE

To investigate effects of continuous epidural infusion (CEI) of 0.5% bupivacaine added to intermittent epidural boluses (IEB) on the duration of zoster-associated pain (ZAP), as compared with continuous infusion of normal saline placebo added to IEB.

DESIGN

A prospective, double-blind, randomized, placebo-controlled study.

SETTING

A university hospital and an affiliated clinic in Japan from 1996 through 1999.

PATIENTS

56 immunocompetent herpes zoster (HZ) patients, 50 years or older, within 10 days of rash onset and with severe pain and eruption.

INTERVENTIONS

Patients were hospitalized and randomly allocated into 2 groups. CEI group given CEI of 0.5% bupivacaine (0.5-1.0 mL/h) plus IEB of 0.5% bupivacaine 4 times daily (n = 29). IEB group given normal saline infusion plus IEB of 0.5% bupivacaine 4 times daily (n = 27). All patients received oral acyclovir 800 mg, 5 times daily, for 7 days.

OUTCOME MEASURES

The number of days required for complete cessation of ZAP and the proportion of subjects with allodynia beyond 30 days.

RESULTS

The median time to cessation of ZAP was significantly shorter in the CEI group than in the IEB group (29 days vs. 40 days, P = 0.002). The number of patients whose allodynia persisted beyond 30 days of treatment was significantly lower in the CEI group than in the IEB group (10% vs. 37%, P = 0.027).

CONCLUSIONS

CEI of 0.5% bupivacaine plus IEB was associated with a shorter duration of ZAP and fewer patients with allodynia beyond 30 days, compared with IEB plus normal saline infusion. Patients at high risk for developing postherpetic neuralgia (PHN) can be managed with intensive therapies at the early stage of disease, such as CEI, which maintains effective analgesia and may reduce the burden of PHN.

Current management of postherpetic neuralgia

BACKGROUND

The herpes zoster rash occurs when a dormant varicella zoster virus reactivates in dorsal root and cranial nerve ganglia. Pain that persists in the region where this rash occurred after the cutaneous lesions have healed is termed postherpetic neuralgia (PHN). A wide variety of therapies has been used with varying degrees of success to prevent the occurrence of PHN and to reduce pain with established PHN.

REVIEW SUMMARY

In this review, we discuss the clinical presentation of PHN, current strategies for the prevention and management of this disease, and observations that have increased our understanding of the neural mechanisms involved in PHN.

CONCLUSIONS

Several classes of drugs are effective in attenuating the pain and hyperalgesia caused by PHN, but no single drug leads to the complete relief of symptoms. Additional research is needed to improve treatment strategies and define the role of invasive pain management techniques in cases where PHN is associated with intractable pain.

The effects of famciclovir and epidural block in the treatment of herpes zoster

In our previous study, we concluded that an epidural blockade combined with intravenous acyclovir is very effective in treating the acute pain in herpes zoster and postherpetic neuralgia. We evaluated the efficacy of oral famciclovir and epidural blockade on the pain of herpes zoster, compared to acyclovir administered intravenously and epidural blockade. For this purpose, we examined a new group treated with famciclovir and epidural blockade to compare with the group treated with acyclovir and epidural blockade in our previously study. The changes in the intensity of pain, the number of days required for relief of pain, and the total duration of pain were checked. We compared the days required for relief of pain (DRP) and the total duration of pain (TDP) of this group with those of the previous studied group treated with acyclovir and epidural blockade. DRP was significantly less, but TDP was similar. DRP and TDP were significantly lower, if the patients were treated within 7 days of symptom onset. The patients had a shorter DRP regardless of pain type than the previously studied group treated with acycolvir and epidural blockade. For the severe and moderate pain grades, there was a shorter DRP from 100 to 10. TDP was not significantly different for the groups regardless of pain type or grade. We believe that famciclovir and epidural blockade are very effective in treating the pain of herpes zoster, with a view to shortening the period of acute pain, providing similar effects on the prevention of postherpetic neuralgia, and being convenient to administer, compared to intravenous acyclovir and epidural blockade in our previous study.

Prevention of post-herpetic neuralgia: acyclovir and prednisolone versus epidural local anesthetic and methylprednisolone

BACKGROUND

Treatment of herpes zoster (HZ) includes the use of acyclovir with or without steroids. An alternative therapy is the epidural administration of local anesthetics with or without steroids. This trial compared the efficacy of these two treatment regimens in the prevention of post-herpetic neuralgia (PHN).

METHODS

Six hundred adults over 55 years of age with a rash of less than 7 days duration, and severe pain due to HZ, were enrolled and randomized to receive either intravenous acyclovir (10 mg/kg three times daily) for 9 days+prednisolone (60 mg per day with progressive reduction) for 21 days, or 6-12 ml bupivacaine (0.25%) every 6-8 or 12 h+methylprednisolone 40 mg every 3-4 days by epidural catheter during a period ranging from 7 to 21 days. Efficacy was evaluated at 1, 3, 6 and 12 months. PHN was assessed as pain and/or allodynia, and "abnormal sensations" (hypoesthesia, burning, itching, etc.). Statistical analysis was performed based on the intent-to-treat population.

RESULTS

In the 485 patients who completed the study, the incidence of pain after 1 year was 22.2% (51 patients of 230) after acyclovir+steroids, and 1.6% (4 patients of 255) after epidural analgesia+steroids. The incidence of abnormal sensations was 12.2% (28 patients) after acyclovir+steroids, and 4.3% (11 patients) in group B.

CONCLUSIONS

Epidural administration of local anesthetic and methylprednisolone is significantly more effective in preventing PHN at 12 months compared to intravenous acyclovir and prednisolone.

The role of sympathetic nerve blocks in herpes zoster and postherpetic neuralgia

The most common complication of herpes zoster in immunocompetent patients is postherpetic neuralgia (PHN). Sympathetic blocks have been traditionally used for patients with herpes zoster and PHN with three different therapeutic goals: pain relief during acute herpes zoster, pain relief during PHN, and prevention of PHN by treating patients with acute zoster. The role of sympathetic blocks in herpes zoster and PHN remains controversial due to methodologic shortcomings in published studies and the limited current understanding of the role of the sympathetic nervous system in mediating pain. Current theories of the pathophysiology of PHN, the role of the sympathetic nervous system in herpes zoster and PHN, and published studies investigating use of sympathetic nerve blocks in herpes zoster and PHN are reviewed.

Treatment of postherpetic neuralgia: an update

Postherpetic neuralgia (PHN) is a chronic pain syndrome that is often refractory to treatment and can last for years, causing physical and social disability, psychological distress, and increased use of the healthcare system. In this paper we provide an update on recent developments in the treatment of PHN. We emphasise the results of recent studies that provide an evidence-based approach for treating PHN that was not available until very recently. In randomised, controlled clinical trials, the topical lidocaine patch, gabapentin, and controlled release oxycodone have been shown to provide superior pain relief in patients with PHN when compared with placebo. It has also recently been demonstrated that the tricyclic antidepressant nortriptyline provides equivalent analgesic benefit when compared with amitriptyline, but is better tolerated. Based on these results, nortriptyline can now be considered the preferred antidepressant for the treatment of PHN, although desipramine may be used if the patient experiences unacceptable sedation from nortriptyline. The topical lidocaine patch, gabapentin and controlled release oxycodone all appear to be as effective as tricyclic antidepressants in the treatment of patients with PHN, and the results of these recent studies suggest that each of these treatments should be considered early in the course of treatment. Additional controlled trials are needed to compare the efficacy and tolerability of these 4 treatments- tricyclic antidepressants, gabapentin, the topical lidocaine patch and controlled release opioid analgesics--used singly and in various combinations in the treatment of patients with PHN.

Current and Future Management of Herpes Zoster

Herpes zoster (shingles) is a common disease affecting approximately three in 1000 of the population per year and up to 10 in 1000 per year in the elderly population. This incidence is likely to increase as the proportion of elderly people in the general population increases and various forms of immunosuppression become more common, e.g. following organ transplantation. Management of both the acute and chronic pain is probably the most important part of caring for shingles patients. Antiviral therapy, anti-inflammatory steroids and sympathetic nerve blocks are the main measures used during the acute phase to prevent the development of postherpetic neuralgia (PHN). Antiviral agents given early in the acute phase of herpes zoster are generally the therapy of choice and there is also growing evidence for benefit with tricyclic antidepressants. Pain relief once PHN has developed is generally much less effective. Many classes of drug have been investigated for the management of PHN and some have been found to be helpful in some patients. There is as yet no generally effective agent, however preventive antiviral therapy early in the course of herpes zoster is recommended for all elderly patients since they have a high risk of developing severe PHN.