Antiviral therapy of acute herpes zoster in older patients

Treatment of herpes zoster ophthalmicus: a systematic review and Canadian cost-comparison

OBJECTIVE

A systematic review and cost comparison were conducted to determine the optimal treatment of active herpes zoster ophthalmicus (HZO) in immunocompetent adults.

DESIGN

A literature search of MEDLINE, EMBASE, CINAHL, Cochrane Library, BIOSIS Previews and Web of Science, ClinicalTrials.gov, International Clinical Trials Registry Platform, Networked Digital Library of Theses and Dissertations, and Canadian Health Research Collection was performed. The search period was from January 1990 to March 2017.

PARTICIPANTS

Collectively, 516 immunocompetent patients with active HZO treated with oral antivirals were included.

METHODS

Randomized controlled trials (RCTs) investigating treatment of active HZO in immunocompetent adults, with one oral acyclovir monotherapy arm, were included. Studies fulfilling inclusion criteria were subjected to quality assessment and data extraction. Provincial drug formularies were consulted to extrapolate cost comparison for investigated treatment regimens.

RESULTS

A total of 1515 titles and abstracts and 9 full-text articles were assessed. Three RCTs met the inclusion criteria. Treatment with oral acyclovir (800 mg 5 times daily for 10 days) was superior to placebo in the prevention of ocular manifestations. Oral famciclovir (500 mg 3 times daily for 7 days) and valacyclovir (1000 mg 3 times daily for 7 days) resulted in comparable rates of ocular manifestations relative to oral acyclovir (800 mg 5 times daily for 7 days). According to provincial drug formulary data, famciclovir and valacyclovir are more affordable across Canada with the recommended dosing schedules.

CONCLUSIONS

Oral famciclovir and valacyclovir are reasonable alternatives to oral acyclovir for treatment of active HZO in immunocompetent individuals. Their simpler dosing schedules are associated with a cost benefit that is consistent across Canada.

Probiotics: can they be used to improve oral health?

The role of probiotic bacteria in improving human health has been an attractive subject for researchers since the beginning of the 20(th) century. They have been used to control gastro-intestinal infections, to promote immunity and to prevent various diseases (allergies, urogenital infections, etc.). However, the use of beneficial bacteria in the field of dentistry has only recently gained interest. Investigation of the effects of probiotic bacteria on oral health has become an important research subject. These studies are still in the early stages, however results show that probiotic bacteria are effective against tooth caries, periodontal disease, oral mucosal lesions and oral malodour. This review provides information on the effects of probiotics--well-known for their effects on general health, and therefore more widely used in healthcare--on oral and dental health, in order to promote their use/prescription by physicians and patients.

Opioids and the management of chronic severe pain in the elderly: consensus statement of an International Expert Panel with focus on the six clinically most often used World Health Organization Step III opioids (buprenorphine, fentanyl, hydromorphone, methadone, morphine, oxycodone)

SUMMARY OF CONSENSUS: 1. The use of opioids in cancer pain: The criteria for selecting analgesics for pain treatment in the elderly include, but are not limited to, overall efficacy, overall side-effect profile, onset of action, drug interactions, abuse potential, and practical issues, such as cost and availability of the drug, as well as the severity and type of pain (nociceptive, acute/chronic, etc.). At any given time, the order of choice in the decision-making process can change. This consensus is based on evidence-based literature (extended data are not included and chronic, extended-release opioids are not covered). There are various driving factors relating to prescribing medication, including availability of the compound and cost, which may, at times, be the main driving factor. The transdermal formulation of buprenorphine is available in most European countries, particularly those with high opioid usage, with the exception of France; however, the availability of the sublingual formulation of buprenorphine in Europe is limited, as it is marketed in only a few countries, including Germany and Belgium. The opioid patch is experimental at present in U.S.A. and the sublingual formulation has dispensing restrictions, therefore, its use is limited. It is evident that the population pyramid is upturned. Globally, there is going to be an older population that needs to be cared for in the future. This older population has expectations in life, in that a retiree is no longer an individual who decreases their lifestyle activities. The "baby-boomers" in their 60s and 70s are "baby zoomers"; they want to have a functional active lifestyle. They are willing to make trade-offs regarding treatment choices and understand that they may experience pain, providing that can have increased quality of life and functionality. Therefore, comorbidities--including cancer and noncancer pain, osteoarthritis, rheumatoid arthritis, and postherpetic neuralgia--and patient functional status need to be taken carefully into account when addressing pain in the elderly. World Health Organization step III opioids are the mainstay of pain treatment for cancer patients and morphine has been the most commonly used for decades. In general, high level evidence data (Ib or IIb) exist, although many studies have included only few patients. Based on these studies, all opioids are considered effective in cancer pain management (although parts of cancer pain are not or only partially opioid sensitive), but no well-designed specific studies in the elderly cancer patient are available. Of the 2 opioids that are available in transdermal formulation--fentanyl and buprenorphine--fentanyl is the most investigated, but based on the published data both seem to be effective, with low toxicity and good tolerability profiles, especially at low doses. 2. The use of opioids in noncancer-related pain: Evidence is growing that opioids are efficacious in noncancer pain (treatment data mostly level Ib or IIb), but need individual dose titration and consideration of the respective tolerability profiles. Again no specific studies in the elderly have been performed, but it can be concluded that opioids have shown efficacy in noncancer pain, which is often due to diseases typical for an elderly population. When it is not clear which drugs and which regimes are superior in terms of maintaining analgesic efficacy, the appropriate drug should be chosen based on safety and tolerability considerations. Evidence-based medicine, which has been incorporated into best clinical practice guidelines, should serve as a foundation for the decision-making processes in patient care; however, in practice, the art of medicine is realized when we individualize care to the patient. This strikes a balance between the evidence-based medicine and anecdotal experience. Factual recommendations and expert opinion both have a value when applying guidelines in clinical practice. 3. The use of opioids in neuropathic pain: The role of opioids in neuropathic pain has been under debate in the past but is nowadays more and more accepted; however, higher opioid doses are often needed for neuropathic pain than for nociceptive pain. Most of the treatment data are level II or III, and suggest that incorporation of opioids earlier on might be beneficial. Buprenorphine shows a distinct benefit in improving neuropathic pain symptoms, which is considered a result of its specific pharmacological profile. 4. The use of opioids in elderly patients with impaired hepatic and renal function: Functional impairment of excretory organs is common in the elderly, especially with respect to renal function. For all opioids except buprenorphine, half-life of the active drug and metabolites is increased in the elderly and in patients with renal dysfunction. It is, therefore, recommended that--except for buprenorphine--doses be reduced, a longer time interval be used between doses, and creatinine clearance be monitored. Thus, buprenorphine appears to be the top-line choice for opioid treatment in the elderly. 5. Opioids and respiratory depression: Respiratory depression is a significant threat for opioid-treated patients with underlying pulmonary condition or receiving concomitant central nervous system (CNS) drugs associated with hypoventilation. Not all opioids show equal effects on respiratory depression: buprenorphine is the only opioid demonstrating a ceiling for respiratory depression when used without other CNS depressants. The different features of opioids regarding respiratory effects should be considered when treating patients at risk for respiratory problems, therefore careful dosing must be maintained. 6. Opioids and immunosuppression: Age is related to a gradual decline in the immune system: immunosenescence, which is associated with increased morbidity and mortality from infectious diseases, autoimmune diseases, and cancer, and decreased efficacy of immunotherapy, such as vaccination. The clinical relevance of the immunosuppressant effects of opioids in the elderly is not fully understood, and pain itself may also cause immunosuppression. Providing adequate analgesia can be achieved without significant adverse events, opioids with minimal immunosuppressive characteristics should be used in the elderly. The immunosuppressive effects of most opioids are poorly described and this is one of the problems in assessing true effect of the opioid spectrum, but there is some indication that higher doses of opioids correlate with increased immunosuppressant effects. Taking into consideration all the very limited available evidence from preclinical and clinical work, buprenorphine can be recommended, while morphine and fentanyl cannot. 7. Safety and tolerability profile of opioids: The adverse event profile varies greatly between opioids. As the consequences of adverse events in the elderly can be serious, agents should be used that have a good tolerability profile (especially regarding CNS and gastrointestinal effects) and that are as safe as possible in overdose especially regarding effects on respiration. Slow dose titration helps to reduce the incidence of typical initial adverse events such as nausea and vomiting. Sustained release preparations, including transdermal formulations, increase patient compliance.

Corticosteroids for preventing postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia is a common serious complication of herpes zoster. Corticosteroids are anti-inflammatory and might be beneficial.

OBJECTIVES

To examine the efficacy of corticosteroids in preventing postherpetic neuralgia.

SEARCH STRATEGY

Search for randomised or quasi-randomised controlled trials for corticosteroids for preventing postherpetic neuralgia in MEDLINE (1950 to 2006), EMBASE (1980 to 2006), LILACS (1982 to 2005), the Chinese Biomedical Retrieval System (1978 to 2006) and the Cochrane Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 3, 2006). Date of most recent search: September 2006.

SELECTION CRITERIA

Types of studies: quasi-randomised or randomised controlled trials.

TYPES OF PARTICIPANTS

people of all ages with herpes zoster of all degrees of severity within seven days after onset. Types of interventions: all kinds of corticosteroids given by oral, intramuscular or intravenous routes during the acute stage (starting within one week of onset of the rash) compared with no treatment or placebo, but not with other treatments. We also included trials which compared corticosteroids plus routine treatment with placebo plus routine treatment. Types of outcome measures: Primary: the presence of postherpetic neuralgia six months after the onset of the acute herpetic rash. Secondary: pain severity measured by a validated visual analogue scale or numerical descriptive scale after three, six and 12 months; quality of life measured with the short form 36 questionnaire after six months; adverse events during or within two weeks after stopping treatment.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent reviewers.

MAIN RESULTS

Five trials were included with altogether 787 participants. All were randomised, double-blind, placebo-controlled parallel group studies. Our primary outcome measure was the presence of postherpetic neuralgia six months after the onset of the acute herpetic rash. There was no significant difference between the corticosteroid and control groups for the primary outcome (RR 1.27, 95% CI 0.20 to 7.97). There was also no significant difference between the corticosteroid plus antiviral agents and placebo plus antiviral agents groups for the primary outcome (RR 0.90, 95% CI 0.40 to 2.03). No included trials evaluated pain severity with a validated visual analogue scale or numerical descriptive scale and also no trials measured quality of life with the Short Form 36 questionnaire. Adverse events during or within two weeks after stopping treatment were reported by all five included trials, but after meta-analysis, there was no significant difference in any serious adverse event (death, acute cardiac insufficiency, rash dissemination, bacterial pneumonia or haematemesis) or non serious adverse event (dizziness, nausea, vomiting, hypertension or hyperglycaemia).

AUTHORS' CONCLUSIONS

There was insufficient evidence to conclude that corticosteroids are safe or effective in the prevention of postherpetic neuralgia. More randomised controlled trials with a greater number of participants are needed to determine reliably whether there is real benefit (or harm) from the use of corticosteroid therapy to prevent postherpetic neuralgia. Future trials should measure function and quality of life.

Infection in the elderly

Many functional, demographic, and immunologic changes associated with aging are responsible for increasing the incidence and severity of infectious diseases in the elderly. Management is complicated by age-related organ system changes. Because many of the elderly are on multiple medications for underlying illnesses, antimicrobial therapy needs to be chosen keeping drug interactions and adverse events in mind. Common infections seen in the elderly are infections of skin and soft tissue, urinary tract, respiratory tract, and gastrointestinal tract. Organized and well-funded programs to address infectious disease issues in the elderly are the only way to improve care.

Current management of herpes zoster: the European view

The overall incidence of herpes zoster in Europe is approximately 3 per 1000 people per year and more than 10 per 1000 people per year in those aged >80 years. Post herpetic neuralgia (PHN) is a common debilitating complication of herpes zoster, particularly in patients aged >50 years, in persons with severe pain or rash at presentation, and in those with significant prodromal symptoms. Antiviral drugs can effectively control acute symptoms and, if used early enough in the course of the illness, can help prevent the development of PHN and other complications. However, despite this, many patients do not receive such treatment. The economic impact of zoster and PHN is largely underestimated in Europe. Furthermore, there is considerable variation throughout Europe in the management of herpes zoster. Use of antiviral therapy including the newer potent antiviral agents such as brivudin, which requires less frequent administration than acyclovir, is improving patient outcomes in some European countries. However, in many countries, patient awareness of herpes zoster and, as a result, overall antiviral use is low. Guidelines recommending the use of antiviral agents, particularly in patients at risk of developing PHN, are available but are not widely used. More needs to be done to educate the general public and increase awareness among primary healthcare providers of the benefits of timely and appropriate pharmacological therapy in patients with herpes zoster.

Gabapentin: a pooled analysis of adverse events from three clinical trials in patients with postherpetic neuralgia

BACKGROUND

Gabapentin has been shown to be well tolerated and effective in the management of the pain associated with postherpetic neuralgia (PHN). It is assumed that adverse events occurring with gabapentin are dose related, their frequency and severity increasing with increasing doses.

OBJECTIVE

The aim of this study was to assess the dose dependence of adverse events with gabapentin by determining the relationship between increasing doses of gabapentin and the onset and/or worsening of adverse events in patients with PHN.

METHODS

Data were pooled from 3 randomized, double-blind, placebo-controlled, parallel-group studies of gabapentin that focused on or included patients with PHN. Gabapentin was initiated at 300 mg/d and titrated to maintenance doses of 1800 to 3600 mg/d by day 12 to 24. The analysis of adverse events was based on 3 distinct groups: patients who received gabapentin <1800 mg/d, those who received gabapentin >or=1800 mg/d, and those who received placebo. Patients who were given higher doses of gabapentin had already received lower doses. An adverse event was recorded at the dose of its first onset and recorded again if its severity worsened at a higher dose.

RESULTS

This study included data from 603 patients with PHN: 358 patients (196 [54.7%] women, 162 [45.3%] men; mean [SD] age, 72.3 [10.3] years) received gabapentin, and 245 (133 [54.3%] women, 112 [45.7%] men; mean [SD] age, 73.3 [10.7] years) received placebo. The 3 most common adverse events were dizziness, somnolence, and peripheral edema. Patients receiving gabapentin >or=1800 mg/d had a higher incidence of peripheral edema (7.5%) than those receiving gabapentin <1800 mg/d (1.4%) or placebo (1.6%) (P<0.002, gabapentin >or=1800 mg/d vs placebo). In contrast, the incidence of dizziness and somnolence was not higher in patients receiving gabapentin >or=1800 mg/d compared with those in the other groups. Compared with placebo recipients, patients receiving gabapentin <1800 mg/d reported a significantly greater frequency of dizziness (20.2% gabapentin <1800 mg/d vs 7.4% placebo; P<0.002) and somnolence (14.9% vs 5.8%, respectively; P=0.005). However, at >or=1800 mg/d, rates of dizziness (9.7%) and somnolence (6.9%) were comparable to those with placebo. Discontinuation rates were comparable between patients receiving gabapentin and those receiving placebo.

CONCLUSIONS

In this pooled analysis of adverse-event data from 3 clinical trials in patients with PHN, the incidence of peripheral edema was increased when gabapentin was titrated to >or=1800 mg/d. Dizziness and somnolence, the other most commonly occurring adverse events, were transient and did not occur more frequently or worsen with titration to >or=1800 mg/d. Based on these findings, it does not appear that safety concerns should limit titration of gabapentin to achieve optimal efficacy.

Antifungal and antiviral chemotherapy

Fungal and viral infections are difficult to treat, since fungal infections commonly rebound after suppression by the antifungal agent and current antiviral drugs are only virustatic, allowing the virus to reassert its pathogenicity if not eliminated by the host defenses. In addition, fungal infections commonly are associated with significant biofilms, retarding drug penetration, and the fluid nature of the oral cavity does not promote drug-fungus contact for long periods of time. Both mycotic and viral pathogens are developing sophisticated methods to elude the toxic effects of drugs intended to eliminate their existence. The drug therapy of oral fungal and viral infections is therefore limited but occasionally successful (more with fungal than viral infections) and is often relegated to palliative care. The specter of drug resistance and its promotion by prolonged, repetitive and frivolous use must always be foremost in the clinician's mind.

Systemic lupus erythematosus in the elderly

Aging modifies the clinical presentation and course of autoimmune disorders, although the mechanisms by which this occurs remain to be determined. Current evidence cited above supports the general concept that there is a natural senescence of the immune system. This evidence would suggest that somehow senescence directly affects gene expression, resulting in biochemical abnormalities that culminate in T-cell immunodysfunctions. This may be a principal factor that attenuates the autoimmune response to self-antigen and, therefore, the disease course. The authors speculate that there is a disorder primary to the T cell in SLE that is expressed as abnormal immunologic responses to self-antigens, resulting in autoimmunity. Although understanding of this primary T cell disorder is still limited, clinicians now know that the T cell harbors abnormal signaling pathways that reflect defective biochemical functions and seem to be genetically regulated. This aberrant signaling would be anticipated to affect both principal T cell subsets. It may hinder the capacity of cells, such as CD8 T cells, to effectively down-regulate the response of autoreactive CD4 helper T cells to autoantigens. Loss of self-regulation would manifest itself as loss of tolerance, a fundamental component of autoimmunity. The future challenge is to understand how aberrant signaling leads to loss of tolerance. Given this underlying genetic susceptibility in an aged individual whose T cells also are undergoing natural senescence, the authors suggest that it is conceivable that a stress factor may tip the balance in the favor of clinical disease. One such factor may be unspecified environmental stimuli. Yet another consideration is an intercurrent illness, such as an infection. It remains to be determined, however, what these environmental stimuli are and how they impact on the immune system to trigger disease.

Novel agents for the therapy of varicella-zoster virus infections

Varicella-zoster virus (VZV), a member of the herpesvirus family, is responsible for both primary (varicella or chickenpox) as well as recurrent (zoster or shingles) infections. Acyclovir has been the mainstay for treating VZV infections in both immunocompetent and immunocompromised patients. Recently, newer anti-VZV drugs, i.e., valaciclovir (the oral prodrug form of acyclovir) and famciclovir (the oral prodrug form of penciclovir) have been developed and have enlarged the therapeutic options to treat VZV infections. Both acyclovir and penciclovir are dependent on the virus-encoded thymidine kinase (TK) for their intracellular activation. Although emergence of drug-resistant strains does not occur in immunocompetent patients, several reports have documented the isolation of drug-resistant VZV strains following long-term acyclovir therapy in immunocompromised patients. Mutations at the level of the TK are responsible for development of resistance to drugs that depend on the viral TK for their phosphorylation (i.e., acyclovir and penciclovir). Foscarnet, a direct inhibitor of the viral DNA polymerase, which does not require activation by the viral TK, is the drug of choice for the treatment of TK-deficient VZV mutants emerging under acyclovir therapy. Recently, emergence of foscarnet-resistant strains has also been reported. Both TK-deficient strains and foscarnet-resistant mutants are sensitive to the acyclic nucleoside phosphonate cidofovir, CDV, HPMPC, (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine. This agent does not depend on the virus-encoded TK, but on cellular enzymes for its conversion to the diphosphoryl derivative, which then inhibits the viral DNA polymerase.

Current pharmacological approaches to the therapy of varicella zoster virus infections: a guide to treatment

Varicella zoster virus (VZV), a member of the herpesvirus family, is responsible for both primary (varicella, chickenpox) as well as reactivation (zoster, shingles) infections. In immunocompetent patients, the course of varicella is generally benign. For varicella zoster, post-herpetic neuralgia is the most common complication. In immunocompromised patients (particularly those with AIDS), transplant recipients and cancer patients, VZV infections can be life-threatening. For these patients and also for immunocompetent patients at risk such as pregnant women or premature infants, the current treatment of choice is based on either intravenous or oral aciclovir (acyclovir). The low oral bioavailability of aciclovir, as well as the emergence of drug-resistant virus strains, have stimulated efforts towards the development of new compounds for the treatment of individuals with VZV infections. Among these new compounds, penciclovir, its oral prodrug form famciclovir and the oral pro-drug form of aciclovir (valaciclovir), rank among the most promising. As with aciclovir itself, all of these drugs are dependent on the virus-encoded thymidine kinase (TK) for their intracellular activation (phosphorylation), and, upon conversion to their triphosphate form, they act as inhibitors/alternative substrate of the viral DNA polymerase. Therefore, cross-resistance to these drugs may be expected for those virus mutants that are TK-deficient and thus resistant to aciclovir. Other classes of nucleoside analogues dependent for their phosphorylation on the viral TK that have been pursued for the treatment of VZV infections include sorivudine, brivudine, fialuridine, fiacitabine and netivudine. Among oxetanocins, which are partially dependent on viral TK, lobucavir is now under clinical evaluation. Foscarnet, which does not require any previous metabolism to interact with the viral DNA polymerase, is used in the clinic when TK-deficient VZV mutants emerge during aciclovir treatment. TK-deficient mutants are also sensitive to the acyclic nucleoside phosphonates (i.e. [s]-1-[3-hydroxy-2-phosphonylmethoxypropyl]cytosine; HPMPC); these agents do not depend on the virus-encoded TK for their phosphorylation but depend on cellular enzymes for conversion to their diphosphoryl derivatives which then inhibit viral DNA synthesis. Vaccination for VZV has now come of age. It is recommended for healthy children, patients with leukaemia, and patients receiving immunosuppressive therapy or those with chronic diseases. The protection induced by the vaccine seems, to some extent, to include zoster and associated neuralgia. Passive immuniatin based on specific immunoglobulins does not effectively prevent VZV infection and is therefore restricted to high risk individuals (i.e. immunocompromised children and pregnant women).

Early treatment of herpes zoster

Although varicella virus vaccine may eventually decrease the incidence of herpes zoster, the disease will continue to plague patients and physicians for at least the next several decades. Recognition of shingles early in its vesicular stage is important, since that is when antiviral treatment is effective. Moreover, a variety of agents are now available for symptomatic relief of postherpetic neuralgia.