From the Guidelines
Antiviral agents should be prioritized in herpes zoster for patients who are immunocompromised, present within 72 hours of rash onset, and are older than 50 years. The recommended first-line treatments include oral valacyclovir (1000 mg three times daily for 7 days), famciclovir (500 mg three times daily for 7 days), or acyclovir (800 mg five times daily for 7 days) 1. Some key circumstances that warrant prioritization of antiviral agents in herpes zoster include:
- Age older than 50 years
- Rash present less than 72 hours
- Immunocompromised host These circumstances are supported by the most recent and highest quality evidence, which emphasizes the importance of early antiviral therapy in reducing acute pain, accelerating rash healing, and decreasing the risk of postherpetic neuralgia 1. In particular, immunocompromised patients are at a higher risk of developing severe and disseminated herpes zoster, and therefore require prompt and effective antiviral treatment 1. Additionally, patients who present within 72 hours of rash onset are more likely to benefit from antiviral therapy, as it can reduce the severity of acute pain and accelerate cutaneous healing 1. Overall, the use of antiviral agents in herpes zoster should be guided by the principles of reducing morbidity, mortality, and improving quality of life, and should be prioritized in patients who are at highest risk of complications and poor outcomes.
From the FDA Drug Label
There are no data on treatment initiated more than 72 hours after onset of zoster rash Therapy should be initiated at the earliest sign or symptom of herpes zoster and is most effective when started within 48 hours of the onset of rash.
The circumstances under which antiviral agents should be prioritized in herpes zoster are:
- Age older than 50 years is not directly mentioned in the label as a priority.
- Rash present less than 72 hours: Therapy should be initiated as soon as possible after a diagnosis of herpes zoster, and it is most effective when started within 48 hours of the onset of rash.
- Rash present more than 72 hours without new lesion development: There are no data on treatment initiated more than 72 hours after onset of zoster rash.
- Pregnancy: There is no direct information that prioritizes antiviral agents in herpes zoster during pregnancy.
- Immunocompromised host: The label does provide dosing recommendations for immunocompromised patients, but it does not directly state that antiviral agents should be prioritized in these patients for herpes zoster. 2 2 3
From the Research
Circumstances for Prioritizing Antiviral Agents in Herpes Zoster
The following circumstances should be considered for prioritizing antiviral agents in herpes zoster:
- Age older than 50 years: Studies have shown that individuals over 50 years are at a higher risk of developing postherpetic neuralgia (PHN), a common complication of herpes zoster 4, 5.
- Rash present less than 72 hours: Early treatment with antiviral agents within 72 hours of rash onset can help reduce the duration of viral shedding and accelerate lesion resolution 4, 6, 7.
- Immunocompromised host: Immunocompromised patients are at a higher risk of developing severe and complicated herpes zoster infections, and prompt antiviral therapy is recommended to reduce the incidence of cutaneous and visceral dissemination 8.
There is no clear evidence to support prioritizing antiviral agents based on pregnancy or rash present more than 72 hours without new lesion development. However, it is essential to consider the individual patient's circumstances and consult with a healthcare professional for personalized advice.