Treatment of Shingles (Herpes Zoster)
For immunocompetent adults with shingles, initiate oral valacyclovir 1 gram three times daily for 7 days within 72 hours of rash onset, continuing treatment until all lesions have completely scabbed. 1, 2
First-Line Antiviral Therapy for Immunocompetent Patients
Oral antiviral agents are the cornerstone of shingles treatment and should be started as soon as possible, ideally within 48-72 hours of rash onset. 1, 2, 3 The FDA-approved regimens include:
- Valacyclovir 1 gram three times daily for 7 days (preferred due to superior bioavailability and less frequent dosing) 2, 3
- Acyclovir 800 mg five times daily for 7-10 days (effective but requires more frequent dosing) 1, 2
- Famciclovir 500 mg three times daily for 7 days (equivalent efficacy to valacyclovir) 1, 4
The key clinical endpoint is complete scabbing of all lesions, not an arbitrary 7-day duration—continue treatment beyond 7 days if active lesions remain. 1 This is a critical pitfall: stopping antivirals at exactly 7 days when lesions are still forming or vesicular will result in inadequate viral suppression. 1
Treatment initiated after 72 hours may still provide benefit for pain reduction and preventing postherpetic neuralgia, though efficacy is optimal when started within 48 hours. 1, 2, 4 Do not withhold treatment simply because the patient presents beyond the 72-hour window. 1
Treatment for Immunocompromised Patients
Immunocompromised patients require intravenous acyclovir 10 mg/kg every 8 hours for a minimum of 7-10 days and until all lesions have completely scabbed. 1 This includes patients on chemotherapy, with HIV/AIDS, solid organ transplant recipients, or those on chronic immunosuppressive therapy. 1
Consider temporarily reducing immunosuppressive medications in patients with disseminated or invasive herpes zoster, in consultation with the treating specialist. 1 This balances the risk of viral dissemination against the underlying disease requiring immunosuppression.
For HIV-infected patients with uncomplicated dermatomal shingles, higher oral doses may be used: acyclovir 400 mg orally 3-5 times daily until clinical resolution. 5, 1 However, maintain a low threshold for switching to IV therapy if lesions fail to improve within 7-10 days or if dissemination occurs. 5, 1
Special Clinical Scenarios
Facial/Ophthalmic Involvement
Facial herpes zoster requires urgent antiviral therapy due to the risk of ophthalmic complications and cranial nerve involvement. 1 Initiate valacyclovir 1 gram three times daily or famciclovir 500 mg three times daily immediately, with ophthalmology consultation for any periorbital involvement. 1
Disseminated or Severe Disease
Disseminated herpes zoster (multi-dermatomal involvement, visceral involvement, or CNS complications) mandates intravenous acyclovir 10 mg/kg every 8 hours. 1 This applies regardless of immune status. 1
Acyclovir-Resistant Cases
If lesions persist or worsen despite 7-10 days of appropriate antiviral therapy, suspect acyclovir resistance and switch to foscarnet 40 mg/kg IV every 8 hours until clinical resolution. 5, 1 This is most common in severely immunocompromised patients, particularly those with HIV. 5
Critical Monitoring Parameters
Monitor renal function at treatment initiation and once or twice weekly during IV acyclovir therapy, with dose adjustments for creatinine clearance <50 mL/min. 1 Acyclovir can cause acute renal failure, particularly with inadequate hydration. 1
For oral valacyclovir in patients with renal impairment, adjust dosing based on creatinine clearance: CrCl 30-49 mL/min requires 1 gram every 12 hours; CrCl 10-29 mL/min requires 1 gram every 24 hours. 1, 2
What NOT to Do
Never use topical antiviral therapy as primary treatment—it is substantially less effective than systemic therapy and is not recommended. 1 This is a common error in primary care settings.
Do not apply topical corticosteroids to active shingles lesions, as this can worsen viral replication and increase the risk of dissemination, particularly in immunocompromised patients. 1 Systemic corticosteroids (prednisone) may be considered as adjunctive therapy in select cases of severe, widespread disease in immunocompetent patients, but carry significant risks in the elderly and are contraindicated in immunocompromised patients. 1
Avoid using the short-course regimens designed for genital herpes (valacyclovir 500 mg twice daily for 3 days)—these are inadequate for VZV infection. 1, 2
Infection Control
Patients with active shingles should avoid contact with susceptible individuals (those who have never had chickenpox or varicella vaccination) until all lesions have crusted. 1 Lesions are contagious and can transmit varicella to susceptible contacts. 1
Prevention: Vaccination
All adults aged 50 years and older should receive the recombinant zoster vaccine (Shingrix) as a two-dose series (doses given 2-6 months apart), regardless of prior shingles history or previous Zostavax vaccination. 5, 1, 6, 7 Shingrix demonstrates 97.2% efficacy in preventing herpes zoster and maintains protection above 83% for at least 8 years. 6
For patients who have just recovered from shingles, administer Shingrix at least 2 months after acute symptoms have resolved. 6, 7 Having had shingles does not provide reliable protection against future episodes (10.3% recurrence risk at 10 years). 6
Immunocompromised adults aged ≥18 years should receive Shingrix (not the live-attenuated Zostavax, which is contraindicated in this population). 6, 7 For these patients, use a shorter dosing interval with the second dose given 1-2 months after the first. 6