Aciclovir (or acyclovir) 400 mg is an antiviral medication used to treat or prevent viral infections from the herpes family of viruses. It is available as a tablet, suspension, or injection and requires a doctor's prescription.
Shingles and chickenpox: Aciclovir 400 mg is commonly used to treat these infections, which are caused by the varicella-zoster virus.
Genital herpes and cold sores: It is also used to treat outbreaks and can be prescribed for long-term suppression to prevent recurring episodes.
Herpes simplex infections: The medication can treat herpes infections of the skin and mucous membranes and is used as a preventive measure in immunocompromised patients.