Treatment of Shingles in Adults Over 50
For an immunocompetent adult over 50 with shingles, initiate oral valacyclovir 1000 mg three times daily or famciclovir 500 mg three times daily within 72 hours of rash onset, continuing treatment until all lesions have completely scabbed. 1
First-Line Antiviral Therapy
Preferred oral antiviral options:
- Valacyclovir 1000 mg three times daily for 7-10 days 1, 2
- Famciclovir 500 mg three times daily for 7 days 1, 3
- Acyclovir 800 mg five times daily for 7-10 days (requires more frequent dosing but remains effective) 1, 2
Valacyclovir and famciclovir offer superior bioavailability and less frequent dosing compared to acyclovir, which improves patient adherence. 1 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 starting within 48 hours is most effective. 1
Critical Treatment Endpoint
Continue antiviral therapy until all lesions have completely scabbed—this is the key clinical endpoint, not an arbitrary 7-day duration. 1 If lesions remain active beyond 7 days, treatment should be extended. 1 Do not discontinue therapy at exactly 7 days if new lesions are still forming or existing lesions have not scabbed. 1
When to Escalate to Intravenous Therapy
Intravenous acyclovir 10 mg/kg every 8 hours is required for:
- Disseminated herpes zoster (multi-dermatomal or visceral involvement) 1
- Complicated facial zoster with suspected CNS involvement or severe ophthalmic disease 1
- Immunocompromised patients with any herpes zoster 1
- Invasive disease with organ involvement 1
For immunocompromised patients with disseminated or invasive disease, consider temporary reduction in immunosuppressive medications while on IV acyclovir. 1
Pain Management Considerations
While antiviral therapy is the cornerstone of treatment, famciclovir demonstrated superior acute pain relief compared to valacyclovir in patients aged 50 years or older, with significant pain reduction as early as days 3-4. 4 Both famciclovir and valacyclovir reduce the duration of postherpetic neuralgia more effectively than acyclovir, with famciclovir recipients losing postherpetic neuralgia two times faster than placebo (median reduction of 100 days in patients ≥50 years). 3
Renal Dosing Adjustments
Dose adjustments are mandatory for patients with renal impairment to prevent acute renal failure. 1 Acyclovir half-life and total body clearance are dependent on renal function, and geriatric patients have higher plasma concentrations due to age-related renal changes. 2 Monitor renal function at initiation and once or twice weekly during IV acyclovir therapy. 1
Common Pitfalls to Avoid
- Do not use topical antivirals—they are substantially less effective than systemic therapy and are not recommended. 1
- Do not stop treatment at 7 days if lesions are not fully scabbed—this is inadequate for varicella-zoster virus infection. 1
- Do not delay treatment beyond 72 hours—efficacy decreases significantly after this window. 1
- Do not use short-course therapy designed for genital herpes—it is inadequate for shingles. 1
Infection Control
Patients with active shingles should avoid contact with susceptible individuals (those without chickenpox history) until all lesions have crusted, as lesions are contagious. 1 This is particularly important for protecting pregnant women, immunocompromised individuals, and unvaccinated children.
Prevention of Future Episodes
After recovery from the acute episode, administer recombinant zoster vaccine (Shingrix) to prevent future recurrences. 5, 1 The recombinant zoster vaccine is strongly recommended for all immunocompetent adults aged 50 years and older, regardless of prior herpes zoster episodes, with vaccine efficacy of 97.2% across all age groups and protection maintained above 83.3% for up to 8 years. 5