What are the recommended antiviral treatments for shingles?

Recommended Antiviral Treatments for Shingles

For uncomplicated herpes zoster (shingles) in immunocompetent adults, the recommended first-line antiviral treatment is valacyclovir 1000 mg orally three times daily for 7 days, or famciclovir 500 mg orally three times daily for 7 days. 1, 2, 3

First-Line Antiviral Options

1. Valacyclovir

   • Dosage: 1000 mg orally three times daily for 7 days
   • Benefits: Better bioavailability than acyclovir, less frequent dosing, and significantly faster resolution of zoster-associated pain 4
   • Particularly effective when started within 72 hours of rash onset

2. Famciclovir

   • Dosage: 500 mg orally three times daily for 7 days
   • Benefits: Reduces viral shedding, accelerates lesion healing, and significantly reduces duration of postherpetic neuralgia 3
   • Particularly effective in patients ≥50 years old, reducing postherpetic neuralgia duration by approximately 3.5 months 3

3. Acyclovir

   • Dosage: 800 mg orally five times daily for 7 days
   • Less convenient dosing schedule but effective for cutaneous healing
   • May be less effective than valacyclovir for reducing postherpetic neuralgia 4

Special Populations

Severe Cases Requiring Hospitalization

• Acyclovir: 5-10 mg/kg IV every 8 hours for 5-7 days until clinical resolution 1

Acyclovir-Resistant Strains

• Foscarnet: 40 mg/kg IV every 8 hours until clinical resolution 1

Immunocompromised Patients

• Require longer treatment duration and closer monitoring 1
• Consider IV acyclovir for severe cases

Renal Impairment

Dosage adjustments for acyclovir based on creatinine clearance:

• CrCl >25 mL/min: Standard dosing
• CrCl 10-25 mL/min: 800 mg every 8 hours
• CrCl 0-10 mL/min: 800 mg every 12 hours 1

Clinical Pearls

1. Timing is crucial: Antiviral therapy should ideally be initiated within 72 hours of rash onset for maximum effectiveness, though valacyclovir may still provide benefit when started later 4

2. Pain management: Consider adjunctive therapy for pain control:

   • Mild pain: Acetaminophen or NSAIDs
   • Moderate to severe pain: Gabapentin, pregabalin, or tricyclic antidepressants 1

3. Prevention of transmission: Advise patients to avoid close contact with susceptible individuals until lesions have crusted 1

4. Follow-up: Re-examine patients 3-7 days after treatment initiation to assess response 1

5. Consider vaccination: Herpes zoster vaccine is recommended for adults 50 years and older to prevent future outbreaks 1

Comparative Efficacy

• Valacyclovir and famciclovir appear to have similar efficacy in speeding resolution of acute herpes zoster rash and shortening the duration of postherpetic neuralgia 4
• Both valacyclovir and famciclovir offer advantages over acyclovir in terms of dosing convenience and potentially better outcomes for postherpetic neuralgia 3, 4
• Famciclovir has been shown to reduce the median duration of postherpetic neuralgia by 56 days in all patients and by 100 days in patients ≥50 years compared to placebo 3

When selecting an antiviral for shingles treatment, consider the patient's age, renal function, severity of disease, and ability to adhere to the medication regimen. The more convenient dosing schedules of valacyclovir and famciclovir may improve patient compliance and treatment effectiveness.