What are the recommended antivirals (antiviral medications) for the treatment of herpes zoster?

Antiviral Medications for Herpes Zoster Treatment

For the treatment of herpes zoster (shingles), the recommended antiviral medications are oral valacyclovir, famciclovir, or acyclovir, with valacyclovir and famciclovir being preferred due to their more convenient dosing schedules. 1, 2

First-Line Antiviral Options

Uncomplicated Herpes Zoster

• Valacyclovir: 1000 mg three times daily for 7 days 1
• Famciclovir: 500 mg three times daily for 7 days 1, 3
• Acyclovir: 800 mg five times daily for 7-10 days 1, 4

Complicated or Disseminated Herpes Zoster

• Intravenous acyclovir is recommended for patients with complicated herpes zoster (including multi-dermatomal, ophthalmic, visceral, or disseminated disease) 1
• Treatment should continue for a minimum of 7-10 days 1

Special Considerations

Timing of Treatment

• Antiviral therapy should be initiated within 72 hours of rash onset for maximum effectiveness 1, 5
• Treatment should continue at least until all lesions have scabbed 1

Immunocompromised Patients

• All immunocompromised patients with herpes zoster should receive antiviral therapy 1
• Immunosuppressive therapy should be discontinued or reduced in severe cases of varicella infection, disseminated HSV and VZV 1
• High-dose IV acyclovir remains the treatment of choice for VZV infections in severely compromised hosts 1

Pain Management

• Appropriately dosed analgesics in combination with a neuroactive agent (e.g., amitriptyline) should be given together with antiviral therapy 6
• Early treatment with antivirals can reduce the duration and severity of postherpetic neuralgia 3, 5

Comparative Efficacy

• Famciclovir has been shown to reduce the duration of postherpetic neuralgia compared to placebo, with a 3.5-month reduction in median duration for patients 50 years or older 3
• Valacyclovir 1.5 g twice daily has demonstrated similar efficacy to three-times-daily dosing regimens, potentially improving patient compliance 7
• All three oral antivirals (acyclovir, valacyclovir, and famciclovir) have similar efficacy in treating acute herpes zoster symptoms 8

Clinical Pearls and Pitfalls

• Dosing advantage: Valacyclovir and famciclovir have better oral bioavailability than acyclovir and require less frequent dosing, which may improve adherence 8, 2
• Treatment window: While antivirals are most effective when started within 72 hours, they may still provide benefit when started later, especially in patients with ongoing vesicle formation or immunocompromised status 1, 5
• Monitoring: In immunocompromised patients, monitor for signs of cutaneous and visceral dissemination; if these occur, switch to intravenous antiviral therapy 8
• Duration: Antiviral treatment should continue for a minimum of 7-10 days and until all lesions have scabbed 1

By following these evidence-based recommendations for antiviral therapy in herpes zoster, clinicians can effectively manage the acute phase of the disease and potentially reduce the risk of postherpetic neuralgia, particularly in older patients who are at higher risk for this complication.