Treatment of Shingles (Herpes Zoster)
For immunocompetent adults with shingles, initiate oral valacyclovir 1000 mg 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
Recommended oral antiviral regimens:
Valacyclovir 1000 mg three times daily for 7 days is the preferred first-line treatment due to superior bioavailability (3-5 fold higher than acyclovir), less frequent dosing that improves adherence, and proven acceleration of pain resolution compared to acyclovir 2, 3, 4
Famciclovir 500 mg three times daily for 7 days offers equivalent efficacy to valacyclovir with similar dosing convenience 5, 4
Acyclovir 800 mg five times daily for 7-10 days remains effective but requires more frequent dosing, which may reduce compliance 1, 2
Critical timing: Treatment must be initiated within 72 hours of rash onset for optimal efficacy in reducing acute pain, accelerating lesion healing, and preventing postherpetic neuralgia, though some benefit may occur even when started later 1, 3, 4
Treatment Duration and Endpoint
Continue antiviral therapy until all lesions have completely scabbed—this is the key clinical endpoint, not an arbitrary 7-day duration. 1 Treatment may need extension beyond 7 days if lesions remain active, particularly in immunocompromised patients who develop new lesions for 7-14 days and heal more slowly 1
Escalation to Intravenous Therapy
Intravenous acyclovir 10 mg/kg every 8 hours is mandatory for:
- Disseminated herpes zoster (multi-dermatomal involvement, visceral involvement) 1
- Severely immunocompromised patients (active chemotherapy, HIV with low CD4 counts, solid organ transplant recipients) 1
- Complicated facial zoster with suspected CNS involvement or severe ophthalmic disease 1
- Herpes zoster with encephalitis, pneumonitis, or hepatitis 6
Continue IV therapy for a minimum of 7-10 days and until clinical resolution is attained, with close monitoring of renal function and dose adjustments as needed. 1
Special Population Considerations
Immunocompromised Patients
For patients on immunosuppressive therapy (chemotherapy, biologics, high-dose corticosteroids):
- Initiate IV acyclovir 10 mg/kg every 8 hours immediately 1
- Consider temporary reduction in immunosuppressive medications in consultation with the treating specialist 1
- Monitor for dissemination and complications more closely 1
- Extend treatment duration beyond standard 7-10 days as lesions may continue developing for 7-14 days 1
HIV-Infected Patients
For HIV-positive patients with herpes zoster, higher oral doses may be needed (acyclovir 400 mg 3-5 times daily until clinical resolution), and consideration should be given to long-term acyclovir prophylaxis (400 mg 2-3 times daily) 1, 6
Facial and Ophthalmic Involvement
Facial zoster requires particular attention due to risk of cranial nerve complications and vision-threatening disease 1. Initiate oral valacyclovir 1000 mg three times daily or famciclovir 500 mg three times daily within 72 hours, with urgent ophthalmology consultation for suspected ophthalmic involvement 1
Management of Acyclovir-Resistant Cases
If lesions persist or progress despite adequate antiviral therapy, suspect acyclovir resistance and obtain viral culture with susceptibility testing. 1 For proven or suspected acyclovir-resistant herpes zoster, switch to foscarnet 40 mg/kg IV every 8 hours until clinical resolution, as all acyclovir-resistant strains are also resistant to valacyclovir and most to famciclovir 1, 6
Adjunctive Therapies and What to Avoid
Corticosteroids: Prednisone may be used as adjunctive therapy to antivirals in select cases of severe, widespread shingles, but carries significant risks (infections, hypertension, myopathy, osteopenia) particularly in elderly patients, and should generally be avoided in immunocompromised patients due to increased risk of disseminated infection 1
Topical antivirals are substantially less effective than systemic therapy and are NOT recommended. 1
Infection Control
Patients with shingles must avoid contact with susceptible individuals (those who have not had chickenpox or vaccination) until all lesions have crusted, as lesions are contagious and can transmit varicella. 1
Prevention: Vaccination After Acute Episode
After recovery from acute shingles, administer the recombinant zoster vaccine (Shingrix) as a 2-dose series (second dose 2-6 months after first) once acute symptoms have resolved, typically waiting at least 2 months after the episode. 1, 7, 8 Having shingles once does not provide reliable protection against future episodes, with a 10-year cumulative recurrence risk of 10.3% 1, 7
Shingrix is recommended for all adults aged 50 years and older regardless of prior herpes zoster episodes, with vaccine efficacy of 97.2% and protection persisting for at least 8 years. 7, 8
Common Pitfalls to Avoid
- Do not stop treatment at exactly 7 days if lesions are still forming or have not completely scabbed—continue until all lesions have crusted 1
- Do not use oral acyclovir doses designed for genital herpes (400 mg TDS) for shingles—this is inadequate for VZV infection 1
- Do not delay IV therapy in immunocompromised patients with disseminated disease—oral therapy is insufficient 1
- Do not apply topical corticosteroids to active shingles lesions—this can worsen infection and increase dissemination risk, particularly in immunocompromised patients 1
- Do not use live-attenuated Zostavax vaccine in immunocompromised patients—only Shingrix (recombinant vaccine) is appropriate 1, 7, 8
Monitoring Parameters
- Monitor renal function closely during IV acyclovir therapy with dose adjustments as needed for renal impairment 1
- Assess for thrombotic thrombocytopenic purpura/hemolytic uremic syndrome in immunocompromised patients receiving high-dose therapy 1
- If lesions fail to begin resolving within 7-10 days, suspect acyclovir resistance and obtain viral culture with susceptibility testing 1