Acyclovir

Acyclovir works by slowing the growth and spread of the herpes virus so the body can fight off the infection. It does not cure herpes but lessens the symptoms.

Dosage by Body Weight

Pediatric dosing for chickenpox is typically 20 mg/kg (max 800 mg) per dose, four times daily for 5 days. Must be started within 24 hours of rash onset for best effect.

Body Weight
10-20 kg
Dose
200 mg to 400 mg
Frequency
Four times daily
Tracking Notes
Ensure adequate hydration to protect the kidneys.
Body Weight
21-40 kg
Dose
400 mg to 800 mg
Frequency
Four times daily
Tracking Notes
Continue the full course even if symptoms improve.

Weight-based dosage tracking table for Acyclovir, including body weight, dose, frequency, and tracking notes.
Body Weight	Dose	Frequency	Tracking Notes
10-20 kg	200 mg to 400 mg	Four times daily	Ensure adequate hydration to protect the kidneys.
21-40 kg	400 mg to 800 mg	Four times daily	Continue the full course even if symptoms improve.

Formulation

TabletSuspensionOintmentInjection

Purpose

Antiviral medication used to treat infections caused by herpes viruses, including chickenpox, shingles, and cold sores.

Generic Name

Acyclovir

Branded Drug Names

Acyclovir is listed as a generic drug name. Common branded medicines that may contain the same active ingredient include:

Scheduled Drug

Yes. This medicine should be supplied or used only according to applicable prescription and regulatory requirements.

Alternatives

Valacyclovir Famciclovir

Safety Advice

Alcohol

CAUTION

Acyclovir: Alcohol may worsen dizziness, nausea, dehydration, or liver strain during antiviral treatment. Avoid or limit alcohol.

Pregnancy

SAFE IF PRESCRIBED

Acyclovir: Use during pregnancy only when prescribed; treatment may be important for maternal infection control or prevention of transmission.

Breast Feeding

SAFE IF PRESCRIBED

Acyclovir: Breastfeeding advice depends on the infection and treatment regimen. Use only with healthcare provider guidance.

Driving

CAUTION

Acyclovir: May cause dizziness, fatigue, sleep disturbance, or headache. Avoid driving if alertness is affected.

Liver

CAUTION

Acyclovir: Some antivirals can affect liver function or require monitoring in hepatitis, HIV, or severe illness.

Kidney

CAUTION

Acyclovir: Several antivirals are cleared by the kidneys and may need dose adjustment or hydration. Consult your healthcare provider.