Treatment of Chickenpox
For chickenpox treatment, intravenous acyclovir is recommended for 7-10 days for patients with varicella zoster virus infection, particularly those who are immunocompromised or at high risk for complications. 1, 2
Recommended Treatment Based on Patient Population
Immunocompetent Children
- Children <40 kg: Oral acyclovir 20 mg/kg (maximum 400 mg/dose) 4 times daily for 5 days 2, 3
- Children >40 kg: Oral acyclovir 800 mg 4 times daily for 5 days 4, 3
- Treatment should be initiated within the first 24 hours of rash onset for maximum effectiveness 5
Immunocompetent Adults
- Oral acyclovir 800 mg 4-5 times daily for 7-10 days 2, 4
- Treatment is particularly important for adults as they have higher risk of complications compared to children 6
High-Risk Patients (requiring treatment)
- Patients over 12 years of age 2, 4
- Immunocompromised individuals 1, 2
- Patients with chronic cutaneous or pulmonary disorders 2, 4
- Patients receiving long-term salicylate therapy or corticosteroids 2, 4
- Pregnant women with serious varicella complications 4
Immunocompromised Patients
- Intravenous acyclovir 10 mg/kg every 8 hours for 7-10 days 1, 2
- Some experts recommend dosing based on body surface area (500 mg/m²/dose IV every 8 hours) for children over 1 year 4
- Immunomodulator therapy should be discontinued in severe cases if possible 2
Post-Exposure Prophylaxis
- For susceptible individuals exposed to chickenpox (those with no history of chickenpox or vaccination), VZV immunoglobulins (VZIG) should be administered as soon as possible within 96 hours of exposure 1, 2
- If VZIG is not available, prophylactic treatment with oral acyclovir (10 mg/kg four times a day for 7 days) within 7-10 days of exposure to chickenpox is recommended 1, 2
- This approach may be effective for reducing the severity of chickenpox symptoms 1
Dosage Adjustments
- For patients with renal impairment, acyclovir dosage should be modified based on creatinine clearance 3:
- CrCl >25 mL/min: 800 mg every 4 hours, 5 times daily
- CrCl 10-25 mL/min: 800 mg every 8 hours
- CrCl <10 mL/min: 800 mg every 12 hours
- Hemodialysis patients should receive an additional dose after each dialysis session 3
Clinical Evidence and Benefits
- Acyclovir treatment reduces the number of varicella lesions (mean 294 vs. 347 with placebo) 5
- Treated patients have fewer severe cases with >500 lesions (21% vs. 38% with placebo) 5
- Treatment accelerates healing, reduces itching, and limits fever and constitutional symptoms to 3-4 days 5
- New lesion formation typically stops after day 3 in treated patients 5
Important Considerations
- Diagnosis of VZV infection relies on clinical features with or without PCR detection of the virus in vesicle samples 1
- Antibody titers are not informative in patients with nephrotic-range proteinuria or those receiving IVIG infusions 1
- Acyclovir does not eradicate latent virus or affect the risk of future recurrences 4
- Patients should be isolated until all lesions have crusted over to prevent transmission 2
Caveats and Pitfalls
- Treatment should be initiated as early as possible, ideally within 24 hours of rash onset, as delayed treatment significantly reduces effectiveness 7, 5
- Adequate hydration must be maintained during treatment, especially with high-dose or IV administration 8
- Mental status should be monitored in patients receiving high-dose IV therapy 8
- Antibody titers after infection in children receiving acyclovir do not differ substantially from those not receiving treatment 4