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Peds Calc

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Acyclovir Indications & Clinical Uses

Evidence-based guide for pediatric prescribing

Acyclovir is the cornerstone antiviral for HSV and VZV in pediatrics. Rapid initiation limits viral replication, shortens symptom duration, and decreases complications such as dehydration, eczema herpeticum, and neonatal dissemination.

Primary FDA-Approved Indications

Use acyclovir when clinical presentation and risk factors indicate significant viral burden—particularly in severe primary infections, immunocompromised hosts, or high-risk varicella exposures.

Primary HSV gingivostomatitis

FDA Approved
Children 6 months and olderRandomized trial

Use aggressively in patients with poor oral intake or risk of hospitalization to shorten illness and improve feeding.

Evidence Sources

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Eczema herpeticum

FDA Approved
Infants and children with atopic dermatitisSpecialist consensus

Initiate within 24 hours of diagnosis—ophthalmology consult if periocular lesions present.

Evidence Sources

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Varicella (high-risk hosts or complicated disease)

FDA Approved
Children and adolescentsModerate

High-risk groups include immunocompromised children, chronic lung disease, secondary household cases <24 months, and adolescents. Start within 24 hours of rash onset when possible.

Evidence Sources

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Secondary Clinical Uses

HSV suppression in immunocompromised or frequent recurrent disease

Secondary Use
Children and adolescentsModerate

Consider in children with ≥6 mucocutaneous outbreaks per year, eczema herpeticum history, or undergoing chemotherapy/stem-cell transplantation.

Evidence Sources

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Off-Label Uses

Note: Off-label uses may be clinically appropriate based on evidence and expert consensus, but are not FDA-approved for these indications. Always consider the evidence base and document clinical reasoning.

Recurrent HSV labialis prophylaxis in adolescents

Off-Label
Adolescents

400 mg PO twice daily for 4–6 months may reduce outbreak frequency; reassess benefit versus adherence burdens periodically.

Evidence Sources

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•Evidence quality: 85/10
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