Aciclovir eye ointment for herpes simplex infection

This leaflet is for parents and carers about how to use this medicine in children. Our information may differ from that provided by the manufacturers, because their information usually relates to adults. Read this leaflet carefully. Keep it somewhere safe so that you can read it again.

Name of medicine

Aciclovir 3% eye ointment

Common brand: Zovirax®

Why is it important for my child to take Aciclovir eye ointment?

Herpes simplex virus can cause an infection in the eye.

Aciclovir slows the growth and spread of the virus so that your child’s body can fight off the infection. 

What is Aciclovir eye ointment available as?

  • 3% eye ointment: 4.5 g tube

When should I give Aciclovir eye ointment

Aciclovir ointment is usually applied five times a day. This is usually first thing in the morning, at about midday, late in the afternoon, early in the evening and at bedtime. Ideally, these times should be approximately 4 hours apart.

Apply the ointment at about the same time(s) each day so that this becomes part of your child’s daily routine, which will help you to remember.

You must continue using the eye ointment for 3 days after the eye has got better. 

How much should I give?

Your doctor will work out the amount of Aciclovir eye ointment (the dose) that is right for your child. The dose will be shown on the medicine label.

It is important that you follow your doctor’s instructions about how much to give.

How should I give Aciclovir eye ointment?


  • Use the Aciclovir eye ointment only into the infected eye, unless your doctor has told you to treat both.
  • Wash your hands thoroughly with soap and hot water before and after giving the ointment.
  • The ointment is easiest to give when your child is lying down.
  • For older children, gently pull the lower lid out and squeeze the bottle gently so that a small amount (about 1 cm) goes into the pocket that is formed.
  • In small children and babies, place the ointment into the inner corner of the eye, preferably with the eye open.
  • After giving ointment, your child should blink several times to help dissolve the ointment.
  • If you think the ointment didn’t go into the eye, you can repeat the process but do not try more than twice.
  • Wash your hands thoroughly with soap and water after giving the ointment. This will help to stop the virus spreading.

Try to avoid the tip of the tube touching any part of your child’s eye.

When should the medicine start working?

The medicine should start working straight away and your child’s eye infection will start to get better within a few days.

What if my child is sick (vomits)?

You do not need to worry if your child is sick, as the medicine will still work.

What if I forget to give it?

Give the next dose as soon as you remember but make sure there is at least 2 hours between each application.

What if I give too much?

It is unlikely to do harm if you give an extra dose of Aciclovir eye ointment or if your child accidentally swallows Aciclovir eye ointment. However, if you are worried, contact your doctor or local NHS services (details at end of leaflet). Have the medicine or packaging with you if you telephone for advice.

Are there any possible side effects?

We use medicines to make our children better, but sometimes they have other effects that we don’t want (side effects).

Side effects you must do something about

If your child is short of breath or is wheezing, or their face, lips or tongue start to swell, or they develop a rash, they may be allergic to Aciclovir eye ointment. Take your child to hospital or phone for an ambulance straight away.

Other side-effects you need to know about

Your child is unlikely to get side-effects with Aciclovir cream. Any side-effects that do occur are usually mild and will wear off after a few days.

  • Your child’s eyes are likely to be irritated and inflamed because of their eye infection. They may also be dry or sore, and your child may be sensitive to bright light. The medicine should make these symptoms better but if they get worse it could be a side effect of the medicine. Contact your doctor if you are worried, but do not stop giving the medicine. 
  • When you apply the ointment, your child’s eyes may sting slightly, or their eyesight may become blurred (fuzzy). This should go away after a few minutes.

There may sometimes be other side effects that are not listed above. If you notice anything unusual and are concerned, contact your doctor. You can report any suspected side effects to a UK safety scheme at

Can other medicines be given at the same time as Aciclovir eye ointment?

  • You can give your child medicines that contain paracetamol or ibuprofen, unless your doctor has told you not to.

Is there anything else I need to know about this medicine?

  • It is important that your child completes the course of Aciclovir. This means that they must use the ointment for the number of days that the doctor has told you to. Your child’s eye infection will probably go away in a few days but it takes a few more days for Aciclovir to completely treat the infection. If you stop giving it too soon, the viruses will start to multiply again and the eye infection may come back.
  • Aciclovir does not kill all the herpes viruses and some will remain in your child’s body. If symptoms of an eye infection return at any time (red, painful or watering eyes), it is important that you get a new prescription of Aciclovir eye ointment from your doctor

General advice about medicines

  • Try to give medicines at about the same times each day, to help you remember.
  • If you are not sure a medicine is working, contact your doctor but continue to give the medicine as usual in the meantime. Do not give extra doses, as you may do harm.
  • Only give this medicine to your child. Never give it to anyone else, even if their condition appears to be the same, as this could do harm.
  • Make sure that the medicines you have at home have not reached the ‘best before’ or ‘use by’ date on the packaging. Give old medicines to your pharmacist to dispose of.

Where should I keep this medicine?

  • Keep the medicine in a cupboard, away from heat and direct sunlight.
  • It does not need to be kept in the fridge.
  • Make sure that children cannot see or reach the medicine.
  • Keep the medicine in the container it came in.

Who to contact for more information?

Your child’s doctor, pharmacist or nurse will be able to give you more information about Aciclovir eye ointment and about other medicines used to treat herpes simplex infection.

England: NHS 111

Tel 111

Scotland: NHS 24

Northern Ireland: NI Direct

Wales: NHS Direct

Tel 111 (free) or 0845 46 47 (2p per minute)

Copyright disclaimer

Version [1]. © NPPG, RCPCH and WellChild, all rights reserved. Review by July 2016.

The primary source for the information in this leaflet is the British National Formulary for Children. For details on any other sources used for this leaflet, please contact us through our website,

We take great care to make sure that the information in this leaflet is correct and up-to-date. However, medicines can be used in different ways for different patients. It is important that you ask the advice of your doctor or pharmacist if you are not sure about something. This leaflet is about the use of these medicines in the UK, and may not apply to other countries. The Royal College of Paediatrics and Child Health (RCPCH), the Neonatal and Paediatric Pharmacists Group (NPPG), WellChild and the contributors and editors cannot be held responsible for the accuracy of information, omissions of information, or any actions that may be taken as a consequence of reading this leaflet.