Oral acyclovir for herpes zoster: a double-blind controlled trial in normal subjects

Comparing Prodrugs with Acyclovir for Treating Postherpetic Neuralgia among Herpes Zoster Patients: A Systematic Review and Meta-Analysis

Postherpetic neuralgia (PHN) is a common, painful, and long-term complication of herpes zoster (HZ). PHN increases the demand for healthcare services and, previous studies showed that patients who received antiviral agents were less likely to develop PHN. The objective of this study was to compare the efficacy of prodrugs and acyclovir in treating PHN among patients with HZ. The search included the PubMed, Medline, Embase, and Cochrane Center of Register of Controlled Trails databases through February 2022. Clinical trials and randomized controlled trials (RCTs) involving antiviral agent intervention for HZ patients diagnosed with PHN were eligible for inclusion. A meta-analysis was conducted to calculate pooled risk ratios (RRs) with 95% confidence intervals (CIs) with a fix-effect model. Five RCTs with 1147 HZ patients met our eligibility criteria. Our meta-analysis found that there was a significantly lower risk of PHN for members of the prodrugs group (famciclovir and valaciclovir) compared with those who received acyclovir (RR = 0.86, 95%, CI: 0.75 to 0.98, p = 0.03). The review of studies indicated that the efficacy of prodrugs was better than acyclovir for reliving PHN.

Pharmacological and non-pharmacological strategies for preventing postherpetic neuralgia: a systematic review and network meta-analysis

Background

Postherpetic neuralgia (PHN) is a refractory complication of herpes zoster (HZ). To prevent PHN, various strategies have been aggressively adopted. However, the efficacy of these strategies remains controversial. Therefore, we aimed to estimate the relative efficacy of various strategies used in clinical practice for preventing PHN using a network meta-analysis (NMA).

Methods

We performed a systematic and comprehensive search to identify all randomized controlled trials. The primary outcome was the incidence of PHN at 3 months after acute HZ. We performed both frequentist and Bayesian NMA and used the surface under the cumulative ranking curve (SUCRA) values to rank the interventions evaluated.

Results

In total, 39 studies were included in the systematic review and NMA. According to the SUCRA value, the incidence of PHN was lower in the order of continuous epidural block with local anesthetics and steroids (EPI-LSE), antiviral agents with subcutaneous injection of local anesthetics and steroids (AV + sLS), antiviral agents with intracutaenous injection of local anesthetics and steroids (AV + iLS) at 3 months after acute HZ. EPI-LSE, AV + sLS and AV + iLS were also effective in preventing PHN at 1 month after acute HZ. And paravertebral block combined with antiviral and antiepileptic agents was effective in preventing PHN at 1, 3, and 6 months.

Conclusions

The continuous epidural block with local anesthetics and steroid, antiviral agents with intracutaneous or subcutaneous injection of local anesthetics and a steroid, and paravertebral block combined with antiviral and antiepileptic agents are effective in preventing PHN.

Antiviral treatment for preventing postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is a painful and refractory complication of herpes zoster. Treatments are either partially or totally ineffective for many people with PHN. Antiviral agents, used at the time of the rash, have been proposed as an intervention to prevent the development of PHN. This is the first update since the first publication of the review in 2009.

OBJECTIVES

To assess the effectiveness of antiviral agents in preventing PHN.

SEARCH METHODS

On 26 April 2013, we updated the searches in the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL, MEDLINE, EMBASE, LILACS, and the Chinese Biomedical Retrieval System. We checked the references of published studies to identify additional trials, and contacted authors to obtain additional data. We searched other databases in The Cochrane Library for information for the Discussion and two clinical trials registries for ongoing trials.

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) of antiviral treatment given within 72 hours after the onset of herpes zoster for preventing PHN. There were no language restrictions.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, evaluated the risk of bias in included trials, and extracted and analysed data.

MAIN RESULTS

Six RCTs with a total of 1211 participants were eligible; five trials evaluated oral aciclovir, and one, with 419 participants, evaluated oral famciclovir. We were able to conduct meta-analyses as there were sufficient similarities in the included studies, such as the reporting of the presence of PHN, duration of rash before treatment initiation and treatment regimen. For our primary outcome, based on three trials (609 participants) we found no significant difference between the aciclovir and control groups in the incidence of PHN four months after the onset of the acute herpetic rash (risk ratio (RR) 0.75, 95% confidence interval (CI) 0.51 to 1.11), nor was there a significant difference at six months (RR 1.05, 95% CI 0.87 to 1.27, two trials, 476 participants). In four of the trials (692 participants), there was some evidence for a reduction in the incidence of pain four weeks after the onset of rash. In the trial of famciclovir versus placebo, neither 500 mg nor 750 mg doses of famciclovir reduced the incidence of herpetic neuralgia significantly. The most commonly reported adverse events were nausea, vomiting, diarrhoea and headache for aciclovir, and headache and nausea for famciclovir. For neither treatment was the incidence of adverse events significantly different from placebo. None of the studies were at high risk of bias, although the risk of bias was unclear in at least one domain for all but one study. We found no new RCTs when we updated the searches in April 2013.

AUTHORS' CONCLUSIONS

There is high quality evidence that oral aciclovir does not reduce the incidence of PHN significantly. In addition, there is insufficient evidence to determine the effect of other antiviral treatments; therefore, further well-designed RCTs are needed to investigate famciclovir or other new antiviral agents in preventing PHN. Future trials should pay more attention to the severity of pain and quality of life of participants, and should be conducted among different subgroups of people, such as people who are immunocompromised.

Antiviral treatment for preventing postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is a painful and refractory complication of herpes zoster. Treatments are either partially or totally ineffective for many people with PHN. Antiviral agents, used at the time of the rash, are one of the best-established approaches that may prevent the development of PHN.

OBJECTIVES

To investigate the effectiveness of antiviral agents in preventing PHN.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Register (January 13 2009), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2008, Issue 4), MEDLINE (January 1966 to November Week 3 2008), EMBASE (January 1980 to Week 02 2009), LILACS (January 1982 to 13 January 2009), and the Chinese Biomedical Retrieval System (January 1978 to 13 January 2009). We checked the references of published studies to identify additional trials.

SELECTION CRITERIA

All randomised and quasi-randomised controlled trials for antiviral treatment given within 72 hours after the onset of herpes zoster for preventing PHN irrespective of any language restrictions.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials and evaluated the methodological quality, then extracted and analysed data from the included trials.

MAIN RESULTS

Twenty trials were identified. Twelve trials were excluded and two trials are awaiting classification. Six randomised controlled trials, with a total of 1211 participants were eligible; five trials evaluated oral acyclovir, and one trial with 419 participants evaluated oral famciclovir. There was no significant difference between the oral acyclovir and control groups on the incidence of PHN four months (risk ratio (RR), 0.75; 95% CI 0.51 to 1.11; P = 0.15) or six months (RR 1.05, 95% CI 0.87 to 1.27; P = 0.62) after the onset of the acute herpetic rash. There was some evidence for a reduction in the incidence of pain four weeks after the onset of rash. In the trial of famciclovir versus placebo, neither 500 mg and 750 mg doses of famciclovir reduced the incidence of herpetic neuralgia significantly.

AUTHORS' CONCLUSIONS

Oral acyclovir did not reduce the incidence of PHN significantly. There is insufficient evidence from randomised controlled trials to determine whether other antiviral treatments prevent PHN. Additional well-designed, randomised controlled trials of famciclovir or other new antiviral agents, with a greater number of participants are needed. Future trials should pay more attention to the severity of pain and quality of life of participants, and should be conducted among different subgroups of people, such as people who are immunocompromised.

Valacyclovir and prednisolone treatment for Bell's palsy: a multicenter, randomized, placebo-controlled study

OBJECTIVE

To investigate the effects of valacyclovir and prednisolone in comparison with those of placebo and prednisolone for the treatment of Bell's palsy, excluding zoster sine herpete.

STUDY DESIGN

Prospective, multicenter, randomized placebo-controlled study.

SETTING

Six academic tertiary referral centers.

PATIENTS

Ultimately, 221 patients with Bell's palsy who were treated within 7 days of the onset. Serological and polymerase chain reaction examinations were performed to distinguish Bell's palsy from zoster sine herpete.

INTERVENTION

The patients were treated with either valacyclovir (dosage, 1,000 mg/d for 5 days) plus prednisolone (VP [n = 114]) or placebo plus prednisolone (PP [n = 107]) administered orally.

MAIN OUTCOME MEASURE

Recovery from the palsy was defined as a score higher than 36 using Yanagihara 40-point scoring system without facial contracture or synkinesis. The patients were followed up until complete recovery occurred or for more than 6 months in cases with a poor prognosis.

RESULTS

The overall rate of patient recovery among those treated with VP (96.5%) was significantly better (p < 0.05) than the rate among those treated with PP (89.7%). The rate of patient recovery was also analyzed by classifying the initial severity of facial palsy. In cases of complete or severe palsy, the rates of patients treated with VP and PP who recovered were 95.7% (n = 92) and 86.6% (n = 82), respectively; the recovery rate for treatment with VP was significantly better than that with PP (p < 0.05).

CONCLUSION

The valacyclovir and prednisolone therapy was more effective in treating Bell's palsy, excluding zoster sine herpete, than the conventional prednisolone therapy. To our knowledge, this is the first controlled study of an antiviral agent in the treatment of a sufficient number of Bell's palsy cases based on an etiologic background.

Efficacy of Early Treatment of Bell's Palsy With Oral Acyclovir and Prednisolone

OBJECTIVE

To investigate the therapeutic effects of acyclovir and prednisolone in relation to the timing of treatment in Bell's palsy.

STUDY DESIGN

This was a retrospective study of 480 Bell's palsy patients who were treated with oral acyclovir and prednisolone (94 cases) or prednisolone alone (386 cases).

PATIENTS

Patients met the after criteria: (1) severe or complete Bell's palsy with a score lower than 20 on the 40-point Yanagihara facial score and (2) treatment started within 7 days after onset. The patients were treated with oral prednisolone (60-40 mg/day) with or without oral acyclovir (2,000 mg/day).

MAIN OUTCOME MEASURE

Rate of recovery, which was defined as a facial score of 36 or more, and the absence of contracture with synkinesis.

RESULTS

The overall recovery rate of patients treated with acyclovir and prednisolone was 95.7 percent, which was better than that of patients treated with prednisolone alone (88.6%). The recovery rate in patients who began the combined therapy within 3 days of the onset of palsy was 100 percent and early treatment resulted in early remission. In contrast, the recovery rate in patients who started the combined therapy more than 4 days after onset was 86.2 percent.

CONCLUSION

These results suggest that early diagnosis and treatment within 3 days of the onset of paralysis are necessary for maximal efficacy of combined acyclovir and prednisolone therapy for Bell's palsy.

Oral antivirals revisited in the treatment of herpes zoster: what do they accomplish?

Oral antiviral agents currently represent the most important therapeutic keystone in the treatment of herpes zoster. Three oral antiviral agents are available for the treatment of herpes zoster: acyclovir, its derivative valacyclovir, and famciclovir. Meta-analysis of published data has shown that oral acyclovir significantly reduces various herpes zoster-related symptoms as well as the duration, intensity and prevalence of zoster-associated pain (ZAP). However, this drug does not influence postherpetic neuralgia. The newer agents famciclovir and valacyclovir exhibit a better oral bioavailability than acyclovir. These agents have demonstrated similar efficacy to acyclovir with ZAP and they require less frequent administration. When initiated within 72 hours, oral antiviral therapy of herpes zoster is beneficial in selected, elderly immunocompetent patients, reducing the duration and intensity of ZAP and providing more rapid skin lesion healing. Oral antivirals are also of benefit in immunocompromised patients with uncomplicated herpes zoster. However, signs of cutaneous and visceral dissemination should be monitored; if signs occur, intravenous antiviral therapy is indicated.

Antiviral therapy of acute herpes zoster in older patients

Although herpes zoster (shingles) can occur in anyone with a history of chickenpox, it is more prevalent and usually more severe in older patients (i.e. persons over 50 years of age). While the cutaneous manifestations of shingles usually resolve in approximately 4 weeks, the pain can persist for several months, or even years in the untreated patient. This pain following healing of the skin, termed post-herpetic neuralgia (PHN), can be very severe. Three well tolerated and effective antiviral drugs are available for the therapy of acute herpes zoster. The nucleoside analogues, aciclovir, famciclovir and valaciclovir, appear to shorten the duration of PHN to a similar degree, but none affects the incidence of PHN. Aciclovir is taken 5 times daily for 7 days, while famciclovir is taken 3 times daily for 7 days. Valaciclovir, the L-valyl ester of aciclovir, when taken orally, produces plasma levels of aciclovir equivalent to those seen following intravenous administration of aciclovir. Valaciclovir has not only been proved to be more efficient than aciclovir (i.e. 3 times daily administration) but also more effective than aciclovir in shortening the duration of PHN. Current studies are determining the relative efficacy of valaciclovir versus famciclovir. Presently, a fourth drug, sorivudine, is being compared with aciclovir for the therapy of acute herpes zoster in older patients, but data from these trials are not yet available. Corticosteroids have been used to treat herpes zoster for much longer than the antiviral drugs, but the effect of corticosteroids on PHN does not appear to be consistent. Corticosteroids plus aciclovir did not provide an added benefit over aciclovir alone in one study but this combination did appear to improve the quality of life of older patients in another investigation. The recent availability of the varicella zoster vaccine may cause shingles to be an uncommon and/or mild disease by the mid twenty-first century. Meanwhile, the search continues for more effective and efficient therapies for acute herpes zoster with the primary goal in older patients to affect the most important sequela of zoster in this population, PHN.

Early diagnosis and treatment of Ramsay Hunt syndrome: the role of magnetic resonance imaging

We present the case of a 47-year-old woman with left otalgia, rotatory vertigo, sensorineural hearing loss and acute facial nerve palsy. An enhanced magnetic resonance imaging (MRI) scan showed discrete enhancement of the facial and vestibulocochlear nerves in the left internal auditory canal as well as of the labyrinth. This appearance was compatible with that in Ramsay Hunt syndrome and acyclovir was started prior to the appearance of any vesicular eruption. The diagnosis was subsequently confirmed serologically. She regained full facial function but the sensorineural hearing loss persisted. The literature pertaining to the role of the MRI in acute facial palsies is reviewed.

Recognition and treatment of shingles

Varicella zoster virus (VZV) is responsible for a primary infection (varicella) followed by a latency, eventually resulting in herpes zoster (shingles). The replication cycle of VZV is normally interrupted after varicella. Consequently, VZV remains dormant in the organism. Reactivation occurs after viraemia, and the development of tissue alterations (skin and viscera) depends on the immunological status of the patient. Diagnosis of herpes zoster relies on clinical recognition and cytological and histological evaluations combined with immunohistochemistry and molecular biology techniques. Treatment of herpes zoster primarily relies upon antiviral drugs and incidentally on immunomodulating agents, specific immunoglobulins, antimicrobial agents, antiviral enzymes and corticosteroids. Drugs with a clinically relevant activity against varicella zoster virus infections include aciclovir, adenosine monophosphate, bromodeoxyuridine, desciclovir, fiacitabine, idoxuridine, interferon-alpha and vidarabine. Among them, aciclovir appears to be a first-line agent. Its efficacy has been well established by many clinical studies. Promising drugs for the future include famciclovir, penciclovir, valaciclovir and other molecules currently under investigation. Recent and promising improvements in antiviral drug development may increase patient compliance, cost-benefit ratios and therapeutic efficacy.

Current experience with antiviral therapy for acute herpes zoster

Inhibition of varicella-zoster virus replication during acute herpes zoster would, theoretically, accelerate cutaneous healing and reduce the pain, both acute and chronic, associated with shingles. Early antiviral drugs were of limited efficacy, excessively toxic, or needed to be given parenterally, and were unsuitable for use in immunocompetent individuals. Acyclovir was a significant advance and remains the antiviral drug of choice for herpes zoster. There is ample evidence for its efficacy in acute illness, but its ability to influence post-herpetic neuralgia is controversial. This review also discusses the role of adjunctive therapy with steroids in acute shingles.

A retrospective and an observational study with acyclovir

Retrospective analysis: This open controlled non-randomized study was carried out to investigate the influence of intravenous acyclovir (ACV) on the incidence of post-herpetic neuralgia (PHN). Twelve women and 11 men (mean age 52 years, range 19-89) received ACV 5 mg/kg every 8 hours) for 10 days (I). Twenty-seven untreated patients (mean age 62 years, range 20-89) were taken as a control group (II). Six to 24 months after the onset of herpes zoster (shingles) the patients were reexamined. The analysis revealed a significantly lower incidence of both general pain and severe pain (P < 0.05, chi 2 = 5.55 and 4.39) for (I) compared to (II). For 21 patients who were treated for a period of 10 days, the significance level was 1% (chi 2 = 7.82 and 8.62). Observational study: Fifteen thousand eight hundred and thirty-one non-hospitalized patients with shingles (mean age 55.2 years) received oral ACV (800 mg five times daily) for 7 days. At the onset of therapy, 15,420 patients (97.6%) reported pain (severe 42.6%, moderate 43.1%, mild 14.3%). The pain during treatment was documented by the patients (n = 5,728) in a diary and transferred to a scoring system (0 = none, 1 = mild, 2 = moderate, 3 = severe). From day 1 to day 7 there was a decrease in the pain score level from 2.3 to 0.9. Three months after the onset of herpes zoster, 2,519 of 14,858 patients (16.95%) reported pain; 311 patients (2.1%) complained of continuous pain, typical for PHN.(ABSTRACT TRUNCATED AT 250 WORDS)

A double-blind, placebo-controlled study of oral acyclovir in postherpetic neuralgia

Twenty-one patients with postherpetic neuralgia of two- to 84-months duration participated in a double-blind, placebo-controlled study of oral acyclovir. Pain perception was assessed with the Melzack Pain Questionnaire at baseline and at two-to six-week intervals during the ensuing six months. Clinically significant pain reduction occurred in eight patients: four received acyclovir, and four received a placebo. Several treatment strategies have been advocated for relief of postherpetic neuralgia. Results of the present study demonstrate the need for a double-blind, placebo-controlled paradigm to substantiate the efficacy of new clinical approaches. The same caveat applies to the more common syndromes encountered in psychiatric practice.

Detection of specific IgA antibodies to varicella zoster virus in serum of patients with Ramsay Hunt syndrome

Varicella zoster virus (VZV)-specific IgG and IgA antibody titers were determined in serial serum samples of 23 patients with Ramsay Hunt syndrome by the immunoperoxidase assay. Varicella zoster virus-specific IgG antibodies were found in the first serum samples of all the patients. In 80% of 20 patients in whom a serum sample was available within 5 days after the onset of the disease. VZV-specific IgA antibodies were detected. The second serum sample was VZV-specific IgA-positive in all of the patients. While all the healthy age- and sex-matched control subjects had VZV-specific IgG antibodies, VZV-specific IgA antibodies were detected in a low titer (dilution = 2) in only three of the subjects. By using VZV-specific IgA antibody titers greater than or equal to 2 and greater than or equal to 4 by the immunoperoxidase assay as a "cutoff" for younger and older patients with Ramsay Hunt syndrome, respectively, an early diagnosis of the disease can be obtained in 89% of the younger and in 64% of the older patients by a single serum sample.

Acyclovir and postherpetic neuralgia

Studies have demonstrated the benefit of acyclovir, given intravenously or orally, on the acute illness in herpes zoster (HZ). Whether or not such treatment influences the subsequent development of postherpetic neuralgia (PHN) has been the subject of recent controversy. Intravenous acyclovir has not been shown to influence PHN significantly in prospective studies. Oral acyclovir in large doses may reduce PHN during the 3 months after acute HZ, but this effect has not been observed consistently in well-designed studies. From 3 months onwards, no trial has demonstrated a significant effect of oral acyclovir in reducing PHN. The way forward is discussed.