Aciclovir (or acyclovir) is an antiviral medicine.
It treats a range of infections caused by herpes viruses, including:
Your doctor may prescribe aciclovir to prevent you getting these infections if you've had them before or if you have a weak immune system.
It's also used to treat chickenpox and shingles.
Aciclovir is available on prescription. It comes as tablets, a liquid that you swallow, an eye ointment, a cold sore cream and a cream for genital herpes.
It's sometimes given by injection, but this is usually only done in hospital.
You can buy aciclovir cold sore cream at most pharmacies and shops without a prescription.
Key facts
- Start taking or using aciclovir as soon as you get the first signs of infection.
- For most infections, you should start to feel better after taking or using aciclovir for a few days.
- Common side effects of the tablets and liquid include headaches, feeling dizzy, and feeling or being sick.
- If aciclovir tablets or liquid make you feel dizzy, or if the eye ointment affects your vision, do not drive or cycle until you feel better.
- Wash your hands before and after using the genital herpes cream, cold sore cream or eye ointment.