Treatment of Chickenpox (Varicella)
Acyclovir is the recommended treatment for chickenpox, with dosing regimens varying based on patient age and immune status. 1
Treatment Recommendations by Age Group
Children (2 years and older)
- Oral acyclovir 20 mg/kg per dose 4 times daily (80 mg/kg/day) for 5 days 2
- Children over 40 kg should receive the adult dose 2
- Treatment should be initiated within 24 hours of rash onset for maximum effectiveness 1, 3
Adults and Children over 40 kg
- Oral acyclovir 800 mg 4 times daily for 5 days 2
- Treatment initiated within the first 24 hours of rash provides the greatest benefit 3, 4
Benefits of Acyclovir Treatment
- Reduces the number of varicella lesions (294 vs 347 with placebo) 3
- Accelerates progression to crusted and healed stages 3
- Decreases itching and reduces residual lesions 3
- Limits duration of fever and constitutional symptoms to 3-4 days 3
- Five days of therapy is sufficient, as a 7-day course provides no additional benefit 4
Special Populations
Immunocompromised Patients
- Intravenous acyclovir is indicated for varicella-zoster infections in immunocompromised patients 2
- Treatment should be initiated at the earliest sign or symptom of chickenpox 2
Pregnant Women
- For pregnant women with serious varicella complications, intravenous acyclovir should be considered 1
- Acyclovir is classified as a Category B drug in pregnancy 5, 1
- A registry of 749 pregnancies with first-trimester acyclovir exposure showed no increased rate of birth defects 5, 1, 2
Patients with Renal Impairment
- Dosage adjustment is required based on creatinine clearance 2
- For patients on hemodialysis, an additional dose should be administered after each dialysis session 2
Post-Exposure Prophylaxis
Immunocompromised Individuals
- Varicella-Zoster Immune Globulin (VZIG) is recommended for susceptible immunocompromised patients within 96 hours of exposure 5, 1
Healthy Individuals
- Vaccination is the method of choice for post-exposure prophylaxis in healthy individuals without evidence of immunity 5, 1
Important Clinical Considerations
- Acyclovir does not decrease transmission of varicella or reduce the duration of absence from school 1
- Adequate hydration should be maintained during treatment 2
- The effectiveness of acyclovir decreases if initiated more than 24 hours after rash onset 4
- Viruses shed during therapy remain susceptible to acyclovir and retain normal thymidine kinase function 4
Cautions and Contraindications
- Caution should be exercised when administering acyclovir to patients receiving potentially nephrotoxic agents 2
- Acyclovir should not be administered to people with a history of severe (anaphylactic) reaction to the vaccine or its components 5
- Patients should be advised to maintain adequate hydration 2