Aciclovir (cream)

Sounds like 'ay-SYE-kloe-vir'

Aciclovir cream is an antiviral medicine that is used to treat cold sores. Find out how to apply it safely and the possible side effects.

Aciclovir cream is also known as: 
  • Aciclovir (Ethics)®
  • Viraban®
  • Viratac®
  • Zovirax®
  • Acyclovir

What is aciclovir cream?

Aciclovir cream is an antiviral medicine that is used to treat cold sores on the lips and face. It is not for use in the mouth. Read more about cold sores.

Cold sores are caused by the herpes simplex virus. Aciclovir cream does not kill the virus but it works by preventing the virus from multiplying. This reduces the severity and duration of cold sore symptoms. Studies have found that aciclovir cream reduces pain and symptoms of cold sores by approximately half a day. The cream does not prevent cold sores from coming back. 

How to apply aciclovir cream

Aciclovir cream works best if it is applied to the cold sore as soon as you get the early tingling feeling, before the blisters appear. Aciclovir cream can also be started after the blisters appear. Note: Aciclovir cream is not intended for use inside your mouth or near your eyes.

  • Amount: Apply a thin layer of cream to the affected area, including the outer edges of the cold sore blisters (if present).
  • Dab the cream on to the area rather than rubbing it in. This will minimise any damage to the blisters, which could cause pain. It will also avoid spreading the virus.
  • How often: Use the cream five times a day every four hours during the day (suggested times are 7am, 11am, 3pm, 7pm and 11pm). Continue to use the cream for 5 days. If your cold sores have not healed, you can use the cream for up to 10 days. If symptoms continue for longer than 10 days, see your doctor.
  • Missed dose: If you forget to use the cream, apply it as soon as you remember and then continue using it again at your usual times.
  • Avoid spreading the infection: Remember to wash and dry your hands before and after using aciclovir cream. Cold sores are contagious. It is important to avoid unnecessary touching or rubbing of the area, and not to use a towel on the area if possible, to prevent it from spreading to other areas.

Precautions before using aciclovir cream

Do you have a weakened immune system such as HIV or AIDS? If so, it’s important that you tell your doctor before you start using aciclovir cream. You may need additional or different antiviral treatment.

What are the side effects of aciclovir (cream)?

Like all medicines, aciclovir cream can cause side effects, although not everyone gets them. The cream can cause burning, stinging, itching, redness, drying and flaking at the area where it is applied. These side effects are usually mild and are temporary – they will pass. If side effects continue for a few days, tell your doctor or pharmacist. If you notice sudden swelling of the mouth and lips, or a rash appearing, tell your doctor immediately.

Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product

Learn more

The following links have more information on aciclovir cream.
Zovirax Cold Sore Cream
Medsafe Consumer Information Sheet, NZ
Facial herpes The NZ Herpes Foundation


  1. Valaciclovir – a first line antiviral medicine BPAC, NZ, 2016
  2. Aciclovir (topical) NZ Formulary
  3. Antiviral preparations NZ Formulary
  4. Herpes simplex. DermNet NZ

Additional resources for healthcare professionals

ZOVIRAX® cold sore cream Medsafe, NZ

Credits: Sandra Ponen, pharmacist. Reviewed By: Maya Patel, MPharm PGDipClinPharm, Auckland Last reviewed: 09 Nov 2021