Herpes Zoster Pain Research Articles

Moxibustion for Treating Pain: A Systematic Review

The objective of this study was to assess the evidence for or against the effectiveness of moxibustion as a treatment option for pain. Fourteen electronic databases were searched. Randomized clinical trials (RCTs) testing moxibustion in human patients with pain of any type were considered. Trials using direct or indirect moxibustion were included. Studies comparing moxibustion with other treatments of unproven effectiveness, studies testing moxibustion together with other treatments of unproven efficacy and trials where pain was not a central symptom of the condition were all excluded. The selection of studies, data extraction, and validation were performed independently by two reviewers. Four RCTs met all the inclusion criteria. Others were of poor methodological quality. Two RCTs suggested significant pain reductions for indirect moxibustion in osteoarthritis as compared with drug therapy (n = 200, RR, 1.11; 95% CI of 1.02 to 1.21, p = 0.02, heterogeneity: chi2 = 1.03, p = 0.31, I2 = 3%). The other two RCTs suggested positive effects of indirect or direct moxibustion on pain in scleroma or herpes zoster compared to drug therapy, respectively. We conclude that few RCTs are available that test the effectiveness of moxibustion in the management of pain, and most of the existing trials have a high risk of bias. Therefore, more rigorous studies are required before the effectiveness of moxibustion for the treatment of pain can be determined.

The Incidence and Clinical Characteristics of Herpes Zoster Among Children and Adolescents After Implementation of Varicella Vaccination

The varicella-zoster virus (VZV) vaccine strain may reactivate to cause herpes zoster. Limited data suggest that the risk of herpes zoster in vaccinated children could be lower than in children with naturally acquired varicella. We examine incidence trends, risk and epidemiologic and clinical features of herpes zoster disease among children and adolescents by vaccination status. Population-based active surveillance was conducted among <20 years old residents in Antelope Valley, California, from 2000 through 2006. Structured telephone interviews collected demographic, varicella vaccination and disease histories, and clinical information. From 2000 to 2006, the incidence of herpes zoster among children<10 years of age declined by 55%, from 42 cases reported in 2000 (74.8/100,000 persons; 95% confidence interval [95% CI]: 55.3-101.2) to 18 reported in 2006 (33.3/100,000; 95% CI: 20.9-52.8; P<0.001). During the same period, the incidence of herpes zoster among 10- to 19-year-olds increased by 63%, from 35 cases reported in 2000 (59.5/100,000 persons; 95% CI: 42.7-82.9) to 64 reported in 2006 (96.7/100,000; 95% CI: 75.7-123.6; P<0.02). Among children aged<10 years, those with a history of varicella vaccination had a 4 to 12 times lower risk for developing herpes zoster compared with children with history of varicella disease. Varicella vaccine substantially decreases the risk of herpes zoster among vaccinated children and its widespread use will likely reduce overall herpes zoster burden in the United States. The increase in herpes zoster incidence among 10- to 19-year-olds could not be confidently explained and needs to be confirmed from other data sources.

Acupuncture in acute herpes zoster pain therapy (ACUZoster) – design and protocol of a randomised controlled trial

BackgroundAcute herpes zoster is a prevalent condition. One of its major symptoms is pain, which can highly influence patient's quality of life. Pain therapy is limited. Acupuncture is supposed to soften neuropathic pain conditions and might therefore act as a therapeutic alternative. Objective of the present study is to investigate whether a 4 week semi-standardised acupuncture is non-inferior to sham laser acupuncture and the anticonvulsive drug gabapentine in the treatment of pain associated with herpes zoster.Methods/DesignThree-armed, randomised, placebo-controlled trial with a total follow-up time of 6 months. Up to estimated 336 patients (interim analyses) with acute herpes zoster pain (VAS > 30 mm) will be randomised to one of three groups (a) semi-standardised acupuncture (168 patients); (b) gabapentine with individualised dosage between 900–3600 mg/d (84 patients); (c) sham laser acupuncture. Intervention takes place over 4 weeks, all patients will receive analgesic therapy (non-opioid analgesics: metamizol or paracetamol and opioids: tramadol or morphine). Therapy phase includes 4 weeks in which group (a) and (c) consist of 12 sessions per patient, (b) visits depend on patients needs. Main outcome measure is to assess the alteration of pain intensity before and 1 week after treatment sessions (visual analogue scale VAS 0–100 mm). Secondary outcome measure are: alteration of pain intensity and frequency of pain attacks; alteration of different aspects of pain evaluated by standardised pain questionnaires (NPI, PDI, SES); effects on quality of life (SF 36); analgesic demand; alteration of sensoric perception by systematic quantitative sensory testing (QST); incidence of postherpetic neuralgia; side effects and cost effectiveness. Credibility of treatments will be assessed.DiscussionThis study is the first large-scale randomised placebo controlled trial to evaluate the efficacy of acupuncture compared to gabapentine and sham treatment and will provide valuable new information about the clinical and physiological effects of acupuncture and gabapentine in the treatment of acute herpes zoster pain. The study has been pragmatically designed to ensure that the study findings can be implemented into clinical practice if acupuncture can be shown to be an effective treatment strategy in acute herpes zoster pain.Trial registrationNCT00885586

A randomized, placebo-controlled trial of oxycodone and of gabapentin for acute pain in herpes zoster

Although acute pain in patients with herpes zoster can be severe and has a substantial impact on health-related quality of life, there have been no randomized clinical trials of oral medications specifically for its ongoing treatment. A randomized clinical trial was conducted in which 87 subjects ⩾50 years of age with herpes zoster within 6 calendar days of rash onset and with worst pain in the past 24 h ⩾ 3 on a 0–10 rating scale initiated 7 days of treatment with famciclovir in combination with 28 days of treatment with either controlled-release (CR) oxycodone, gabapentin, or placebo. Subjects were evaluated for adverse effects of treatment, acute pain, and health-related quality of life. The results showed that CR-oxycodone and gabapentin were generally safe and were associated with adverse events that reflect well-known effects of these medications. Discontinuing participation in the trial, primarily associated with constipation, occurred more frequently in subjects randomized to CR-oxycodone (27.6%) compared with placebo (6.9%). Treatment with CR-oxycodone reduced the mean worst pain over days 1–8 ( p = 0.01) and days 1–14 ( p = 0.02) relative to placebo but not throughout the entire 28-day treatment period as pain resolved in most subjects. Gabapentin did not provide significantly greater pain relief than placebo, although the data for the first week were consistent with a modest benefit. By demonstrating that CR-oxycodone is safe, generally adequately tolerated, and appears to have efficacy for relieving acute pain, the results of this clinical trial provide a foundation for evidence-based treatment for acute pain in herpes zoster.

The fallacy of impartiality: competing interest bias in academic publications

The fallacy of impartiality: competing interest bias in academic publications

Mandibular nerve block with local anesthetic and steroid at the oval foramen for the treatment of trigeminal herpes zoster pain

Mandibular nerve block with local anesthetic and steroid at the oval foramen for the treatment of trigeminal herpes zoster pain

Health Care Expenditure Burden of Persisting Herpes Zoster Pain

Pain can persist long after the resolution of herpes zoster, but little is known regarding its health care costs. The objective of this study was to determine the health care expenditures associated with persisting pain following herpes zoster by comparing expenditures for patients with postherpetic neuralgia or subacute herpetic neuralgia with a control group without these conditions. Health care expenditures attributable to persisting pain in herpes zoster patients were calculated using Thomson-Medstat's MarketScan databases to examine commercial, Medicare, and Medicaid claims for inpatient and outpatient services and outpatient prescription drugs. Excess annualized costs were $4,917 for commercially insured patients, $2,696 for Medicare patients, and $9,310 for Medicaid patients. The substantial health care costs associated with persisting pain in herpes zoster have important public health implications given evidence that the incidence of herpes zoster is increasing and that the population is aging in the United States. The results provide a basis for evaluating the cost-effectiveness of existing treatments and emerging prevention strategies.

Diagnosis and Assessment of Pain Associated With Herpes Zoster and Postherpetic Neuralgia

Accurate evaluation of pain plays a critical role in identifying new interventions for the treatment and prevention of herpes zoster and postherpetic neuralgia (PHN). Different types of pain and other sensory symptoms are found in patients with herpes zoster, and these vary greatly with respect to their presence, location, duration, intensity, and quality. The results of recent studies of herpes zoster and PHN and the development of new methods for assessing neuropathic pain provide a foundation for diagnosing and assessing the pain associated with herpes zoster. We review the results of recent research to identify the essential components that must be considered in developing an evidence-based description of pain associated with herpes zoster and PHN. Comprehensive assessments of pain are necessary for clinical research on the epidemiology, natural history, pathophysiologic mechanisms, treatment, and prevention of pain in herpes zoster and PHN.

Natural History and Treatment of Herpes Zoster

The objective of this article is to provide an overview of the natural history and treatment of herpes zoster, with a focus on pain management. Herpes zoster has the highest incidence of all neurological diseases, occurring annually in approximately 1 million people in the United States. A basic feature of herpes zoster is a marked increase in incidence with aging and with diseases and drugs that impair cellular immunity. Herpes zoster begins with reactivation of varicella zoster virus in dorsal root or cranial nerve ganglia, which is often accompanied by a prodrome of dermatomal pain or abnormal sensations. Varicella zoster virus spreads in the affected primary afferent nerve to the skin and produces a characteristic dermatomal maculopapular and vesicular rash and pain. Herpes zoster acute pain lowers quality of life and interferes with activities of daily living. Antiviral therapy and scheduled analgesics form the pharmacotherapeutic foundation for herpes zoster acute pain reduction. If moderate to severe herpes zoster pain is not adequately relieved by antiviral agents in combination with oral analgesic medications, then corticosteroids, anticonvulsants (eg, gabapentin or pregabalin), tricyclic antidepressants (eg, nortriptyline or desipramine), or neural blockade can be considered. This article presents information on the clinical features and treatment of herpes zoster. This information will help clinicians diagnose and manage herpes zoster pain.

The Impact of Acute Herpes Zoster Pain and Discomfort on Functional Status and Quality of Life in Older Adults

To describe the interference of herpes zoster (HZ) pain and discomfort with activities of daily living (ADLs) and health-related quality of life (HRQL) during the acute rash phase, and to quantify the relationship between acute HZ pain and discomfort and impaired ADLs and HRQL in older persons. Prospective, observational study of 160 HZ outpatients age > or =60 at 4 US study sites who completed the Zoster Brief Pain Inventory (ZBPI), Zoster Impact Questionnaire (ZIQ), McGill Pain Questionnaire, EuroQol, and SF-12 questionnaires on a predetermined schedule. Patients rated interference on a 0 to 10 scale for ADL items in the ZBPI and the ZIQ. Interference scores were averaged to create summary measures for the ZBPI items (ZBPI ADLI) and ZIQ items (ZIQ ADLI). A composite pain score was used in mixed-effects models analyses of the association between pain and discomfort and ADLI and HRQL measures during the first 35 days after HZ rash onset. HZ pain interfered with all ADLs but interference was greatest for enjoyment of life, sleep, general activity, leisure activities, getting out of the house, and shopping. For every 1.0 point increase in pain and discomfort intensity, there was a 0.69 and 0.53 point increase in ZBPI and ZIQ interference, respectively, and a 2.81 point, 1.57 point, and 1.95 point decrease in EuroQol, SF-12 physical, and SF-12 mental scales, respectively. Acute zoster pain and discomfort has a significant negative impact on functional status and HRQL in older adults. The magnitude of interference increases with increasing pain and discomfort intensity.

Zoster Vaccine Live

Herpes zoster is a neurocutaneous disease caused by the varicella-zoster virus and is associated with significant morbidity and long-term sequelae in older adults. Until recently, treatment options for these complications have been primarily targeted at disease state management and symptom relief. Zoster vaccine live is the first vaccine approved for the prevention of herpes zoster. The vaccine was approved by the United States Food and Drug Administration for adults aged 60 years or older. Results of the Shingles Prevention Study demonstrated that in older individuals, administration of zoster vaccine live reduces the burden of illness associated with herpes zoster by 61.1%, the frequency of herpes zoster pain and discomfort by 51.3%, and the frequency of postherpetic neuralgia by 66.5%. Overall, adverse events reported in clinical trials of zoster vaccine live were classified as mild. Events that occurred more frequently in zoster vaccine live recipients than in placebo recipients included injection site reactions, headache, respiratory infections, fever, flu syndrome, diarrhea, rhinitis, skin disorders, respiratory disorders, and asthenia. The Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices recently recommended universal vaccination for those 60 years of age and older, including those who have experienced previous episodes of shingles.

Healthcare Costs of Acute and Chronic Pain Associated with a Diagnosis of Herpes Zoster

To determine the healthcare costs of acute and chronic pain associated with herpes zoster. Retrospective cohort analysis. Inpatient and outpatient care. Patients were selected from Medicare, commercial insurance, and Medicaid claims databases if they had a diagnosis of herpes zoster or postherpetic neuralgia (PHN) or were prescribed analgesics after a diagnosis of herpes zoster (possible PHN) and were matched to controls for demographic and clinical factors using propensity scores. One-year excess healthcare expenditures attributable to herpes zoster pain or PHN were calculated for inpatient, outpatient, and prescription drug services. For the Medicare cohort, the average excess cost per patient was $1,300 in the year after a diagnosis of herpes zoster with 30 days or fewer of analgesic use and ranged from $2,200 to $2,300 per patient with PHN or possible PHN. Patients with possible PHN were 53% more prevalent than patients with PHN in the Medicare cohort and accounted for half of all excess expenditures. Findings were similar in the younger cohorts with commercial insurance and Medicaid except that costs attributable to PHN and possible PHN were higher, and patients with possible PHN were three to five times as prevalent as patients with PHN. Healthcare costs associated with PHN were substantially greater than those associated with herpes zoster pain that resolved within 30 days. The data suggest that as many as 80% of patients with PHN may not be diagnosed with PHN and that these patients account for at least half of PHN expenditures.

Post-Herpetic Neuralgia in Older Adults

Many individuals across the globe have been exposed to the varicella-zoster virus (VZV) that causes chickenpox. After chickenpox has resolved, the virus remains latent in the dorsal root ganglia where it can re-emerge later in life as herpes zoster, otherwise known as shingles. Herpes zoster is a transient disease characterised by a dermatomal rash that is usually associated with significant pain. Post-herpetic neuralgia (PHN) is the term used for the condition that exists if the pain persists after the rash has resolved. Advanced age and compromised cell-mediated immunity are significant risk factors for reactivation of herpes zoster and the subsequent development of PHN. Though the pathophysiology of PHN is unclear, studies suggest peripheral and central demyelination as well as neuronal destruction are involved. Both the vaccine against VZV (Varivax) and the newly released vaccine against herpes zoster (Zostavax) may lead to substantial reductions in morbidity from herpes zoster and PHN. In addition, current evidence suggests that multiple medications are effective in reducing the pain associated with PHN. These include tricyclic antidepressants, antiepileptics, opioids, NMDA receptor antagonists as well as topical lidocaine (lignocaine) and capsaicin. Reasonable evidence supports the use of intrathecal corticosteroids, but the potential for neurological sequelae should prompt caution with their application. Epidural corticosteroids have not been shown to provide effective analgesia for PHN. Sympathetic blockade may assist in treating the pain of herpes zoster or PHN. For intractable PHN pain, practitioners have performed delicate surgeries and attempted novel therapies. Although such therapies may help reduce pain, they have been associated with disappointing results, with up to 50% of patients failing to receive acceptable pain relief. Hence, it is likely that the most effective future treatment for this disease will focus on prevention of VZV infection and immunisation against herpes zoster infection with a novel vaccine.

(717): Healthcare expenditures in patients with herpes zoster pain and postherpetic neuralgia

Because existing data on medical costs associated with acute and persisting pain associated with herpes zoster are limited, healthcare expenditures were estimated in patients covered by commercial, Medicare, and Medicaid insurance. The MEDSTAT Group’s Marketscan Databases, composed of medical, pharmacy, and enrollment information, were used. Patients were included if they had evidence of a claim with a primary diagnosis of herpes zoster accompanied by a pain medication prescription or with a primary diagnosis of postherpetic neuralgia (PHN). The index date was first evidence of such a claim from 7/1/2001-12/31/2003. Patient demographics and healthcare expenditures were measured in the 6 months prior to the index date and the following 12 months for the commercial and Medicare cohorts; for the Medicaid cohort, follow-up was only 6 months because data were limited. A propensity score model was used to match controls to each insured cohort, controlling for differences in patient demographics (age, gender, location, insurance type, index year) and health status (Charlson Comorbidity Index, psychiatric diagnostic groups). A total of 1,032 commercial, 811 Medicare, and 604 Medicaid patients with herpes zoster pain or PHN were studied. Prior to matching, the cohorts and controls were significantly different in terms of demographics and health status. After matching, patient demographics were similar, but the health status of the cohorts was still significantly different, with the pain cohorts having greater comorbidities. The difference in average annual healthcare expenditures between the pain cohorts and their matched controls were $4,916 (p<0.01) in a commercial population, $2,695 (p<0.01) in a Medicare population, and $9,312 (p<0.01) in a Medicaid population. The additional healthcare expenditures associated with herpes zoster pain and PHN are considerable, averaging between $2,695 and $9,312 per year per patient depending on the population. Sponsored by grants from Endo Pharmaceuticals to The MEDSTAT Group and the University of Rochester. Because existing data on medical costs associated with acute and persisting pain associated with herpes zoster are limited, healthcare expenditures were estimated in patients covered by commercial, Medicare, and Medicaid insurance. The MEDSTAT Group’s Marketscan Databases, composed of medical, pharmacy, and enrollment information, were used. Patients were included if they had evidence of a claim with a primary diagnosis of herpes zoster accompanied by a pain medication prescription or with a primary diagnosis of postherpetic neuralgia (PHN). The index date was first evidence of such a claim from 7/1/2001-12/31/2003. Patient demographics and healthcare expenditures were measured in the 6 months prior to the index date and the following 12 months for the commercial and Medicare cohorts; for the Medicaid cohort, follow-up was only 6 months because data were limited. A propensity score model was used to match controls to each insured cohort, controlling for differences in patient demographics (age, gender, location, insurance type, index year) and health status (Charlson Comorbidity Index, psychiatric diagnostic groups). A total of 1,032 commercial, 811 Medicare, and 604 Medicaid patients with herpes zoster pain or PHN were studied. Prior to matching, the cohorts and controls were significantly different in terms of demographics and health status. After matching, patient demographics were similar, but the health status of the cohorts was still significantly different, with the pain cohorts having greater comorbidities. The difference in average annual healthcare expenditures between the pain cohorts and their matched controls were $4,916 (p<0.01) in a commercial population, $2,695 (p<0.01) in a Medicare population, and $9,312 (p<0.01) in a Medicaid population. The additional healthcare expenditures associated with herpes zoster pain and PHN are considerable, averaging between $2,695 and $9,312 per year per patient depending on the population. Sponsored by grants from Endo Pharmaceuticals to The MEDSTAT Group and the University of Rochester.

Relief of pain in acute herpes zoster by nerve blocks and possible prevention of post-herpetic neuralgia

This report describes two cases of acute herpes zoster (AHZ) treated by nerve block resulting in immediate pain relief and possible prevention of post-herpetic neuralgia (PHN). Two elderly females with AHZ of cervical dermatomes and severe pain received deep cervical and greater occipital nerve blocks with a local anesthetic, epinephrine and steroid. In both patients, pain resolved immediately and permanently (one year follow-up) after a single treatment. Case #1: A 79-yr-old female with a mechanical mitral valve and anticoagulated with warfarin presented with AHZ of 17 days duration of the right C2, 3, 4 dermatomes and severe pain. A stellate ganglion block was not performed because of anticoagulation. Rather, a deep cervical root block at C3 and a greater occipital nerve block were performed with bupivacaine, epinephrine and methylprednisolone. No adverse events were evident. Case #2: A 73-yr-old female with a history of osteoarthritis and Meniere's disease presented with AHZ of seven days duration of the left C2, 3, 4 dermatomes and severe pain. Deep cervical root blocks at C3 and C4 and a greater occipital nerve block were performed with bupivacaine, epinephrine and methylprednisolone. Side effects of dizziness, hoarseness, hypertension and Horner's syndrome resolved in a few hours. A mild sensation of itching persisted for two weeks. This report illustrates the potential of nerve blocks in severe AHZ to treat acute pain and possibly prevent PHN.

Effect of an Herbal Formula Containing Ganoderma lucidum on Reduction of Herpes Zoster Pain: A Pilot Clinical Trial

Administration of hot water extracts of a herbal formula containing Ganoderma lucidum, WTMCGEPP (Wisteria floribunda 0.38, Trapa natans 0.38, Miristica agrans 0.38, Coix lachryma-jobi 0.75, cultivated Ganoderma lucidum 0.75, Elfuinga applanata 0.38, tissue cultured Panax ginseng 0.3, and Punica granatum 0.38: numerals designate dry weight gram/dose), decreased herpes zoster pain for five Japanese patients suffering from shingles. Pain relief started within a few days of intake and was almost complete within 10 days. Two acute herpes zoster with manifestations including trigeminal nerve ophthalmia (both 74 years old), lower body zoster (70 years old), herpes zoster oticus (17 years old), and leg herpes (28 years old), responded quickly to treatment and no patient developed post-herpetic neuralgia (PHN) after more than one year of follow-up.

Development of a measure of the burden of pain due to herpes zoster and postherpetic neuralgia for prevention trials: Adaptation of the brief pain inventory

Abstract In preparation for clinical trials of a vaccine against herpes zoster (HZ), we conducted a prospective, observational study to evaluate (1) the Zoster Brief Pain Inventory (ZBPI), an HZ-specific questionnaire to quantify HZ pain and discomfort, (2) an operational definition of postherpetic neuralgia (PHN), and (3) a severity-duration measure of the burden of illness caused by HZ. HZ patients aged 60 years or older (n = 121) were enrolled within 14 days of rash onset and completed ZBPI, McGill Pain Questionnaire Present Pain Intensity (PPI), quality of life (QoL), and activities of daily living (ADL) questionnaires on a predetermined schedule. Reliability, measured by intraclass correlation coefficients within 14 days of rash onset, ranged between 0.63 and 0.78. ZBPI pain scores were strongly correlated with other pain measures, interference with ADL, and worsening QoL. The operational definition of PHN, a ZBPI pain score of 3 or greater occurring 90 or more days after rash onset, had high agreement with pain worse than mild on the PPI (kappa = 0.72). The ZBPI pain severity-duration measure had high correlations with severity-duration measures of ADL interference, worsening QoL, and other pain scales. These findings support the validity and utility of the ZBPI, the definition of PHN, and the severity-duration measure of the burden of HZ illness. Perspective Herpes zoster pain, as measured by the ZBPI severity-duration measure, is associated with impairment in daily living activities and quality of life. The ZBPI measure appears useful for quantifying herpes zoster pain, postherpetic neuralgia, and impairment in daily living activities for clinical trials of herpes zoster prevention.

Acute pain in herpes zoster and its impact on health-related quality of life.

Although the effects of postherpetic neuralgia on physical and emotional functioning have been examined in a number of studies, the impact of acute pain in herpes zoster ("shingles") on health-related quality of life has been neglected. We describe the characteristics of herpes zoster pain and examine its relationship to physical, role, social, and emotional functioning in 110 patients with herpes zoster. When we controlled for relevant covariates, we found that greater pain burden, as assessed by the product of pain intensity and duration, was associated with poorer physical functioning, increased emotional distress, and decreased role and social functioning. The results demonstrate that herpes zoster pain has broad effects on the daily lives of patients and on their emotional health. The increasing incidence of herpes zoster that can be anticipated as the population ages requires that clinical trials that examine interventions to prevent or treat herpes zoster pain be given a high priority.

Valacyclovir and Postherpetic Neuralgia

Objective: To describe the role of valacyclovir in the treatment of acute herpes zoster pain and its effect in postherpetic neuralgia. Data Sources: A literature search was conducted on MEDLINE (1980–October 2003). Search terms included valacyclovir, postherpetic neuralgia, treatment, acyclovir, and valacyclovir. Study Selection and Data Extraction: Articles describing use of valacyclovir in the treatment of herpes zoster, with focus upon alleviation of acute zoster pain and postherpetic neuralgia, and articles describing use of valacyclovir for this indication in comparison with other antivirals were evaluated. Data Synthesis: Four studies discussing the use of valacyclovir in the treatment of herpes zoster with focus on herpetic pain and postherpetic neuralgia were identified. All of these studies reported that valacyclovir is an effective treatment for herpes zoster and alleviates associated pain significantly faster than acyclovir, presumably due to its greater bioavailability. Valacyclovir likely results in a higher adherence rate than acyclovir because it is dosed 3 versus 5 times daily. Interestingly, the severity of pain was not significantly different between the 2 treatments, only the duration. Finally, one study showed that valacyclovir is equally as effective as famciclovir in alleviating pain associated with herpes zoster. Conclusions: Valacyclovir 1 g given orally 3 times a day for 7 days is effective in the treatment of herpes zoster. It is superior to acyclovir 800 mg given orally 5 times a day for 7 days and equivalent to famciclovir 500 mg given orally 3 times a day for 7 days in alleviating acute zoster pain and postherpetic neuralgia.

Cancer pain: Classification and pain syndromes)

Inspite the new informations about the physiology and biochemistry of pain, it remains true that pain is only partially understood. Cancer pain is often experienced as several different types of pain, with combined somatic and neuropathic types the most frequently. If the acute cancer pain does not subside with initial therapy, patients experience pain of more constant nature, the characteristics of wich vary with the cause and the involved sites. Chronic pain related to cancer can be considered as tumor-induced pain, chemotherapy-induced pain, and radiation therapy-induced pain. Certain pain mechanisms are present in cancer patients. These include inflammation due to infection, such as local sepsis or the pain of herpes zoster, and pain due to the obstruction or occlusion of a hollow organ, such as that caused by large bowel in cancer of colon. Pain also is commonly due to destruction of tissue, such as is often seen with bony metastases. Bony metastases also produce pain because of periostal irritation, medullary pressure, and fractures. Pain may be produced by the growth of tumor in a closed area richly supplied with pain receptors (nociceptors). Examples are tumors growing within the capsule of an organ such as the pancreas. Chest pain occurring after tumor of the lung or the mediastinum due to invasion of the pleura. Certain tumors produce characteristic types of pain. For example, back pain is seen with multiple myeloma, and severe shoulder pain and arm pain is seen with Pancoast tumors.