About acyclovir
Antiviral medicine
Used for
- Treats herpes simplex infections, including genital herpes and cold sores.
- Treats chickenpox and shingles.
- Helps prevent herpes simplex infections in people with frequent recurrences or weakened immunity.
Usual adult dose
Herpes simplex: 200 mg five times daily for five days. Chickenpox or shingles: 800 mg five times daily for seven days.
Usual dose in children
Chickenpox: 20 mg/kg (maximum 800 mg) four times daily for five days in children aged two years or older.
Common side effects
- Headache or dizziness
- Nausea, vomiting, or diarrhoea
- Abdominal pain
- Skin rash or itching
Important warnings
- Drink enough fluids; kidney problems may require a lower dose.
- Seek urgent care for confusion, severe rash, or signs of an allergic reaction.
- Treatment works best when started promptly; it does not cure herpes or prevent all transmission.
- Dose and duration vary by infection, age, kidney function, and immune status.
Pregnancy
Aciclovir may be used during pregnancy when needed; a clinician weighs benefits and risks.
Breastfeeding
Small amounts enter breast milk; it is generally considered compatible with breastfeeding.
Interactions
- Probenecid can increase aciclovir levels.
- Medicines that affect the kidneys, including ciclosporin or tacrolimus, may increase kidney risks.
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 It may be incomplete or out of date.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.