Treatment of Shingles in Adults
For an adult with shingles, initiate oral antiviral therapy with valacyclovir 1 gram three times daily, famciclovir 500 mg three times daily, or acyclovir 800 mg five times daily, starting within 72 hours of rash onset and continuing until all lesions have completely scabbed. 1, 2
First-Line Oral Antiviral Options
The three FDA-approved oral antivirals are equally effective, but valacyclovir and famciclovir offer superior pharmacokinetics and more convenient dosing:
- Valacyclovir 1000 mg three times daily for 7-10 days - preferred due to better bioavailability and less frequent dosing 1, 2, 3
- Famciclovir 500 mg three times daily for 7 days - equivalent efficacy with convenient dosing 2, 4, 3
- Acyclovir 800 mg five times daily for 7-10 days - effective but requires more frequent dosing 1, 2, 5
Critical timing: Treatment must begin within 72 hours of rash onset for maximum benefit in reducing acute pain, accelerating lesion healing, and preventing postherpetic neuralgia 1, 2, 6
Treatment endpoint: Continue therapy until all lesions have completely scabbed, not just for an arbitrary 7-day period - this is the key clinical endpoint 1, 2
When to Escalate to Intravenous Therapy
Switch to intravenous acyclovir 10 mg/kg every 8 hours for: 1, 2
- Disseminated herpes zoster (multi-dermatomal or visceral involvement)
- Severely immunocompromised patients (HIV, active chemotherapy, transplant recipients)
- Facial zoster with suspected CNS involvement or severe ophthalmic complications
- Patients who cannot tolerate or absorb oral medications
For immunocompromised patients with disseminated disease, consider temporary reduction in immunosuppressive medications while treating with IV acyclovir 1, 2
Special Population Considerations
Immunocompromised patients: May require extended treatment duration beyond 7-10 days, as lesions develop over longer periods (7-14 days) and heal more slowly 1
Renal impairment: Mandatory dose adjustments to prevent acute renal failure: 1, 2
- Valacyclovir: 1 gram every 12 hours for CrCl 30-49 mL/min; 1 gram every 24 hours for CrCl 10-29 mL/min
- Famciclovir: 500 mg every 8 hours for CrCl ≥60 mL/min with appropriate reductions for lower clearance
HIV-infected patients: May require higher doses (acyclovir 400 mg 3-5 times daily) or longer treatment courses 1
Adjunctive Corticosteroid Therapy
Prednisone may be considered as adjunctive therapy in select cases of severe, widespread shingles in immunocompetent patients only 1, 2, 7. However, the benefits are modest - providing only slight improvement in acute pain reduction without reducing postherpetic neuralgia 7.
Absolute contraindications to corticosteroids: 1, 2
- Immunocompromised patients (increased risk of disseminated infection)
- Poorly controlled diabetes
- Severe osteoporosis
- History of steroid-induced psychosis
Critical Pitfalls to Avoid
Never use topical antivirals - they are substantially less effective than systemic therapy and are not recommended 1, 2, 5
Do not stop treatment at exactly 7 days if lesions are still forming or have not completely scabbed - short-course therapy designed for genital herpes is inadequate for VZV infection 1
Monitor renal function at initiation and once or twice weekly during IV acyclovir therapy 1
Suspect acyclovir resistance if lesions fail to begin resolving within 7-10 days - switch to foscarnet 40 mg/kg IV every 8 hours 1
Infection Control
Patients remain contagious until all lesions have crusted and should avoid contact with susceptible individuals (pregnant women, immunocompromised persons, those without prior chickenpox or vaccination) 1, 2
Prevention of Future Episodes
Strongly recommend recombinant zoster vaccine (Shingrix) for all adults aged 50 years and older, regardless of prior shingles episodes, after recovery from the current episode 1, 8, 2. This vaccine reduces the risk of future herpes zoster by over 90% 1. Vaccination should ideally occur before initiating immunosuppressive therapies 1, 2