Pain Management for Herpes Zoster
Antiviral Therapy: The Foundation of Pain Control
Initiate oral valacyclovir 1 gram three times daily or famciclovir 500 mg every 8 hours within 72 hours of rash onset and continue for 7-10 days until all lesions have completely scabbed. 1, 2 This represents the cornerstone of pain management, as early antiviral therapy directly reduces acute pain severity, accelerates healing, and prevents postherpetic neuralgia (PHN)—the most debilitating complication. 1, 3, 4
Antiviral Selection and Dosing
Valacyclovir 1000 mg three times daily for 7 days is first-line for uncomplicated herpes zoster due to superior bioavailability and convenient dosing. 1, 2
Famciclovir 500 mg every 8 hours for 7 days is equally effective and may provide superior acute pain relief compared to valacyclovir, particularly in patients ≥50 years old. 5, 6 One randomized trial demonstrated significantly earlier pain reduction with famciclovir by days 3-4 versus valacyclovir. 6
Acyclovir 800 mg five times daily for 7-10 days remains effective but requires more frequent dosing, which may reduce adherence. 1, 2
Treatment must begin within 72 hours of rash onset for optimal efficacy in reducing acute pain and preventing PHN. 1, 3, 4 However, treatment beyond 72 hours is still warranted if new lesions continue forming or in high-risk patients (age >50, severe pain, extensive rash). 1
Critical Treatment Endpoint
Continue antiviral therapy until all lesions have completely scabbed, not just for an arbitrary 7-day period. 1, 2 This is the key clinical endpoint—if lesions remain active beyond 7 days, extend treatment accordingly. 1
Escalation to Intravenous Therapy
Switch to intravenous acyclovir 5-10 mg/kg every 8 hours for: 1, 2
- Disseminated herpes zoster (multi-dermatomal or visceral involvement)
- Immunocompromised patients with severe disease
- Complicated facial zoster with suspected CNS involvement
- Ophthalmic zoster with severe disease
- Patients unable to tolerate oral therapy
Continue IV therapy until clinical improvement occurs, then transition to oral therapy to complete the treatment course. 2
Adjunctive Pain Management
Acute Pain Control
Acetaminophen or NSAIDs for mild-to-moderate pain during the acute phase. 7
Opioid analgesics may be necessary for severe acute pain, particularly in elderly patients. 7
Avoid topical anesthetics as primary therapy—they provide minimal benefit during the active phase. 1
Corticosteroids: Limited Role
Prednisone may be considered as adjunctive therapy in select cases of severe, widespread disease, but only in immunocompetent patients. 1
Avoid corticosteroids in immunocompromised patients due to increased risk of disseminated infection. 1
The evidence for corticosteroids preventing PHN is weak, and significant risks exist in elderly patients (the primary affected population). 1
Prevention of Postherpetic Neuralgia
Early antiviral therapy with valacyclovir or famciclovir is the only proven intervention to prevent PHN. 8, 3, 4 The combination of antiviral therapy started within 72 hours plus adequate acute pain management provides the best protection against this debilitating complication. 8
PHN Treatment (If It Develops)
If pain persists >90 days after rash onset: 9, 7
Gabapentin (titrate to 1800-3600 mg/day in divided doses) is FDA-approved for PHN and demonstrated efficacy in controlled trials. 9
Pregabalin is an alternative anticonvulsant with similar efficacy. 3
Tricyclic antidepressants (amitriptyline, nortriptyline) in low doses may control neuropathic pain. 7, 3
Lidocaine patches 5% can be applied to affected areas for localized relief. 7, 3
Capsaicin cream may provide benefit but requires consistent application. 7
Special Populations
Immunocompromised Patients
All immunocompromised patients require antiviral treatment regardless of timing. 2
Start with IV acyclovir 10 mg/kg every 8 hours for severely immunocompromised hosts (active chemotherapy, HIV with low CD4 count, solid organ transplant). 1
Consider temporary reduction in immunosuppressive medications in cases of disseminated disease. 1, 2
Treatment duration may need extension beyond 7-10 days as lesions develop over longer periods and heal more slowly. 1
Renal Impairment
Mandatory dose adjustments are required to prevent acute renal failure: 1, 5
Famciclovir: 500 mg every 12 hours for CrCl 40-59 mL/min; 500 mg every 24 hours for CrCl 20-39 mL/min; 250 mg every 24 hours for CrCl <20 mL/min. 5
Monitor renal function at initiation and weekly during treatment, especially with IV acyclovir. 1
Facial/Ophthalmic Zoster
Requires urgent antiviral therapy due to risk of vision-threatening complications and cranial nerve involvement. 1
Ophthalmology consultation is mandatory for any suspected ocular involvement. 7
Consider IV acyclovir for complicated facial zoster with suspected CNS involvement. 1
Common Pitfalls to Avoid
Do not use topical antivirals—they are substantially less effective than systemic therapy. 1, 2
Do not stop treatment at exactly 7 days if lesions are still forming or have not completely scabbed. 1, 2
Do not delay treatment waiting for laboratory confirmation in typical presentations—clinical diagnosis is sufficient. 1
Do not underdose in renal impairment—adjust doses appropriately but ensure adequate antiviral coverage. 1, 5
Do not use short-course regimens designed for genital herpes (e.g., 1-day famciclovir)—these are inadequate for VZV infection. 1
Prevention: Vaccination
The recombinant zoster vaccine (Shingrix) is recommended for all adults ≥50 years regardless of prior herpes zoster episodes. 1, 2 This is the most effective preventive measure and should be offered after recovery from acute infection. 1