Medline ® Abstracts for References 1-6

BACKGROUND: There is no effective treatment for intractable postherpetic neuralgia. Because there is evidence that postherpetic neuralgia has an inflammatory component, we assessed treatment with intrathecally administered methylprednisolone to reduce pain in patients with this disorder.

METHODS: We enrolled 277 patients who had had intractable postherpetic neuralgia for at least one year, 270 of whom were followed for two years. The patients were randomly assigned to receive intrathecal methylprednisolone and lidocaine (3 ml of 3 percent lidocaine with 60 mg of methylprednisolone acetate, 89 patients), lidocaine alone (3 ml of 3 percent lidocaine, 91 patients), or no treatment (90 patients) once per week for up to four weeks. Each weekly dose was injected into the lumbar intrathecal space. Pain was evaluated before randomization, at the end of the treatment period, and then four weeks, one year, and two years later. Samples of cerebrospinal fluid were obtained for measurement of interleukin-8 before and at the end of the treatment period.

RESULTS: There was minimal change in the degree of pain in the lidocaine-only and control groups during and after the treatment period. In the methylprednisolone-lidocaine group, the intensity and area of pain decreased, and the use of the nonsteroidal antiinflammatory drug diclofenac declined by more than 70 percent four weeks after the end of treatment. No complications related to intrathecal methylprednisolone were observed. Before treatment, the concentrations of interleukin-8 in the cerebrospinal fluid were inversely related to the duration of neuralgia in all the patients (r=-0.49, P<0.001). In the patients who received methylprednisolone, interleukin-8 concentrations decreased by 50 percent, and this decrease correlated with the duration of neuralgia and with the extent of global pain relief (P<0.001 for both comparisons).

CONCLUSIONS: The results of this trial indicate that the intrathecal administration of methylprednisolone is an effective treatment for postherpetic neuralgia.

BACKGROUND: The incidence and severity of herpes zoster and postherpetic neuralgia increase with age in association with a progressive decline in cell-mediated immunity to varicella-zoster virus (VZV). We tested the hypothesis that vaccination against VZV would decrease the incidence, severity, or both of herpes zoster and postherpetic neuralgia among older adults.

METHODS: We enrolled 38,546 adults 60 years of age or older in a randomized, double-blind, placebo-controlled trial of an investigational live attenuated Oka/Merck VZV vaccine ("zoster vaccine"). Herpes zoster was diagnosed according to clinical and laboratory criteria. The pain and discomfort associated with herpes zoster were measured repeatedly for six months. The primary end point was the burden of illness due to herpes zoster, a measure affected by the incidence, severity, and duration of the associated pain and discomfort. The secondary end point was the incidence of postherpetic neuralgia.

RESULTS: More than 95 percent of the subjects continued in the study to its completion, with a median of 3.12 years of surveillance for herpes zoster. A total of 957 confirmed cases of herpes zoster (315 among vaccine recipients and 642 among placebo recipients) and 107 cases of postherpetic neuralgia (27 among vaccine recipients and 80 among placebo recipients) were included in the efficacy analysis. The use of the zoster vaccine reduced the burden of illness due to herpes zoster by 61.1 percent (P<0.001), reduced the incidence of postherpetic neuralgia by 66.5 percent (P<0.001), and reduced the incidence of herpes zoster by 51.3 percent (P<0.001). Reactions at the injection site were more frequent among vaccine recipients but were generally mild.

CONCLUSIONS: The zoster vaccine markedly reduced morbidity from herpes zoster and postherpetic neuralgia among older adults.

Seventy-two patients older than 60 years of age who received a diagnosis of herpes zoster (HZ) were entered into a randomized, double-blind, placebo-controlled trial of daily amitriptyline 25 mg. Treatment with either amitriptyline or placebo continued for 90 days after diagnosis. Pain prevalence at 6 months was the primary outcome. Results showed that early treatment with low-dose amitriptyline reduced pain prevalence by more than one-half (p<0.05; odds ratio, 2.9:1) This finding makes a strong case for the pre-emptive administration of amitriptyline, in combination with an antiviral drug, to elderly patients with acute herpes zoster.

The objective of this article is to provide evidence-based recommendations for the management of patients with herpes zoster (HZ) that take into account clinical efficacy, adverse effects, impact on quality of life, and costs of treatment. Systematic literature reviews, published randomized clinical trials, existing guidelines, and the authors' clinical and research experience relevant to the management of patients with HZ were reviewed at a consensus meeting. The results of controlled trials and the clinical experience of the authors support the use of acyclovir, brivudin (where available), famciclovir, and valacyclovir as first-line antiviral therapy for the treatment of patients with HZ. Specific recommendations for the use of these medications are provided. In addition, suggestions are made for treatments that, when used in combination with antiviral therapy, may further reduce pain and other complications of HZ.

Herpes zoster (HZ) results from recrudescence of varicella zoster virus latent since primary infection (varicella). The overall incidence of HZ is approximately 3/1000 of the population per year rising to 10/1000 per year by 80 years of age. Approximately 50% of individuals reaching 90 years of age will have had HZ. In approximately 6%, a second attack may occur (usually several decades after the first). Patients with HZ can transmit the virus to a non-immune individual causing varicella. HZ is not contracted from individuals with varicella or HZ. Reduced cell-mediated immunity to HZ occurs with ageing, explaining the increased incidence in the elderly and from other causes such as tumours, HIV and immunosuppressant drugs. Diagnosis is usually clinical from typical unilateral dermatomal pain and rash. Prodromal symptoms, pain, itching and malaise, are common. The most common complication of HZ is postherpetic neuralgia (PHN), defined as significant pain or dysaesthesia present>or= 3 months after HZ. PHN results from damage and secondary changes within components of the nervous system subserving pain. Some motor deficit is common; severe and long-lasting paresis may rarely accompany HZ. More than 5% of elderly patients have PHN at 1 year after acute HZ. Predictors of PHN are, greater age, acute pain and rash severity, prodromal pain, the presence of virus in peripheral blood as well as adverse psychosocial factors. Therapy for acute HZ is intendedto reduce acute pain, hasten rash healing and reduce the risk of PHN and other complications. Antiviral drugs are close to achieving these aims but do not entirely remove risk of PHN. Oral steroids show no protective effect against PHN. Adequate analgesia during the acute phase may require strong opioid drugs. Nerve blocks and tricyclic antidepressants (TCAs) may reduce the risk of PHN although firm evidence is lacking. PHN requires thorough evaluation and development of a management strategy for each individual patient. Initial therapy is with TCAs (e.g., nortriptyline) or the anticonvulsant gabapentin. Topical lidocaine patches frequently reduce allodynia. Strong opioids are sometimes required. Topical capsaicin cream is beneficial for a small proportion of patients but is poorly tolerated. NMDA antagonists have not proved beneficial with the exception of ketamine. Transcutaneous Electrical Nerve Stimulation (TENS) may be effective in some cases. HZ is a common condition. Severe complications such as stroke, encephalitis and myelitis are relatively rare whereas sight threatening complications of ophthalmic HZ are more common. PHN is common, distressing and often intractable. Good management improves outcome.