About acyclovir
Antiviral nucleoside analogue
Used for
- Treats herpes simplex infections, including cold sores and genital herpes.
- Treats chickenpox and shingles.
Usual adult dose
Herpes simplex: 200 mg five times daily for five days. Shingles: 800 mg five times daily for seven days.
Usual dose in children
Chickenpox: ages 2 years and older, 20 mg/kg four times daily for five days; maximum 800 mg per dose.
Common side effects
- Nausea, vomiting, or diarrhea
- Headache or dizziness
- Skin rash
- Rare kidney or nervous-system problems
Important warnings
- Drink enough fluids; kidney problems may require dose adjustment.
- Start treatment as early as possible for best effect.
- It does not eliminate herpes viruses or reliably prevent transmission.
- Seek urgent help for severe rash, confusion, or reduced urination.
Pregnancy
Use when needed after clinical assessment; available evidence has not shown increased birth-defect risk.
Breastfeeding
Generally considered compatible; small amounts enter breast milk. Monitor for infant diarrhea or rash.
Interactions
- Probenecid can increase acyclovir levels.
- Other medicines affecting the kidneys may increase kidney-related side effects.
- Theophylline levels may rise; monitoring may be needed.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.