Treatment of Varicella Zoster (Chickenpox/Shingles)
For varicella zoster infections, oral antiviral therapy with acyclovir, valacyclovir, or famciclovir is the recommended first-line treatment, with the specific regimen determined by the clinical presentation and immune status of the patient. 1
Treatment Recommendations Based on Clinical Presentation
Uncomplicated Herpes Zoster (Shingles)
- Oral acyclovir 800 mg every 4 hours, 5 times daily for 7-10 days 2
- Alternative options include valacyclovir or famciclovir, which offer better bioavailability and less frequent dosing 1, 3
- Treatment should be initiated as soon as possible after symptom onset for maximum effectiveness 3
Chickenpox (Varicella)
- For children (2 years and older): Acyclovir 20 mg/kg per dose orally 4 times daily for 5 days 2
- For adults and children over 40 kg: Acyclovir 800 mg 4 times daily for 5 days 2
- Treatment should be initiated within 24 hours of symptom onset for best results 2
Severe or Disseminated Disease
- Intravenous acyclovir is indicated for immunocompromised patients or those with severe disseminated disease 1, 2
- Consider switching to oral therapy once clinical improvement is observed 1
Special Populations
Immunocompromised Patients
- High-dose intravenous acyclovir is the treatment of choice 1
- Oral therapy may be used for mild cases or to complete therapy after clinical response to IV treatment 1
- Consider temporary reduction in immunosuppressive medication if applicable 1
HIV-Infected Individuals
- Treatment recommendations are similar to immunocompetent hosts but may require longer treatment duration 1
- Slower healing should be expected 1
Patients with Renal Impairment
- Dose adjustment is required based on creatinine clearance 2:
- For creatinine clearance >25 mL/min/1.73m²: 800 mg every 4 hours, 5 times daily
- For creatinine clearance 10-25 mL/min/1.73m²: 800 mg every 8 hours
- For creatinine clearance <10 mL/min/1.73m²: 800 mg every 12 hours 2
Prevention Strategies
Post-Exposure Prophylaxis
- For susceptible HIV-infected individuals exposed to VZV, varicella-zoster immune globulin (VZIG) should be administered within 96 hours of exposure 4, 1
- If VZIG is unavailable, a 7-day course of oral acyclovir beginning 7-10 days after exposure may be considered 1
Prevention of Recurrence
- No drug has been proven to prevent the recurrence of shingles in immunocompromised or HIV-infected persons 4, 1
- Unlike herpes simplex virus infections, chronic suppressive therapy is not required after VZV lesions resolve 1
Clinical Pearls and Pitfalls
- Early initiation of antiviral therapy (within 72 hours of rash onset) is crucial for reducing the duration and severity of acute symptoms 3, 5
- Famciclovir has been shown to reduce the duration of postherpetic neuralgia compared to placebo, making it a consideration for older patients at risk for this complication 6
- Newer agents like amenamevir (approved in Japan) and valnivudine hydrochloride (FV-100, in development) may represent the future of anti-VZV therapy, especially for cases with resistance to current medications 5
- Cross-resistance can occur among acyclovir, valacyclovir, and famciclovir since they all depend on viral thymidine kinase for activation 7
- For acyclovir-resistant VZV infections, foscarnet may be used as it does not require activation by viral thymidine kinase 7