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Aciclovir (oral) for viral infections

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Oral aciclovir for viral infections

This leaflet is about the use of aciclovir taken by mouth (orally) for the treatment of infections caused by the varicella zoster virus or herpes simplex virus. Aciclovir is known as an antiviral medicine.

Information Standard quality markThis leaflet has been written specifically for parents and carers about the use of this medicine in children. The information may differ from that provided by the manufacturer. Please read this leaflet carefully. Keep it somewhere safe so that you can read it again.

Name of drug

Aciclovir
Brand name:
Zovirax®

Why is it important for my child to take this medicine?

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

What is aciclovir available as?

Tablets: 200 mg, other strengths
Dispersible tablets: 200 mg
Liquid medicine (suspension): 200 mg in 5mL or 400 mg in 5 mL

When should I give aciclovir?

Aciclovir works best when it is given four or five times over 24 hours.

  • For four times a day: ideally this is every 6 hours through the day and night. To not wake a sleeping child, it can be given first thing in the morning, at about midday, late in the afternoon and at bedtime. Ideally these times should be at least 4 hours apart (e.g. 8 am, midday, 4pm and 8pm).
  • For five times a day: ideally, this is every 5 hours through the day and night, but you can give it during the waking day, e.g. 6 am, 10 am, 2 pm, 6 pm and 10 pm.

Give the medicine at about the same times each day so that this becomes part of your child’s daily routine, which will help you to remember.

How much should I give?

Your doctor will work out the amount of aciclovir (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 it?

TabletsTablets should be swallowed with a glass of water, milk or juice. Your child should not chew the tablet.

Dispersing a tablet in waterDispersible tablets should be stirred into a glass of water which will make a cloudy mixture. Your child should then drink it all straight away, or they can sip it over half an hour or so (stir before each sip). You can add squash to the mixture to hide the taste.

Liquid medicine with oral syringeLiquid medicine: Shake the bottle well and measure out the right amount using an oral syringe or medicine spoon. You can get these from your pharmacist. Do not use a kitchen teaspoon as it will not give the right amount.

When should the medicine start working?

Your child should start to feel better after taking the medicine for a few days. It is important that they take the whole course of the medicine that has been prescribed (usually 5 days). Do not stop early, as the viruses may start to multiply again and the infection may return. Your doctor may recommend another 5 day course of medicine.

What if my child is sick (vomits)?

  • If your child is sick less than 30 minutes after having a dose of aciclovir, give them the same dose again.
  • If your child is sick more than 30 minutes after having a dose of aciclovir, you do not need to give them another dose. Wait until the next normal dose.

What if I forget to give it?

Do not give the missed dose. Just give the next dose as usual. If you miss more than one dose, contact your pharmacist or doctor for advice.

Never give a double dose of aciclovir.

What if I give too much?

It may be dangerous to give too much aciclovir.

If you think you may have given your child too much aciclovir, contact your doctor or NHS Direct (0845 4647 in England and Wales; 08454 24 24 24 in Scotland) or take your child to hospital.

Take the medicine container or packaging with you, even if it is empty. This will be useful to the doctor. 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 acyclovir. Take your child to hospital or call an ambulance straight away.

Other side-effects you need to know about

Your child may get some of the following side-effects when they first start taking aciclovir. They should wear off after a few days and will stop when your child stops taking the medicine. If you are worried, contact your doctor but continue to give aciclovir.

  • Your child may feel sick or be sick (vomit) and may get diarrhoea. Giving the medicine with some food or milk may help.
  • They may feel dizzy or light-headed, feel tired or get a headache.
  • Your child may develop itchiness or a rash. Using a moisturising cream or anti-itch cream may help.

There may, sometimes, be other side-effects that are not listed above. If you notice anything unusual and are concerned, contact your doctor.

Can other medicines be given at the same time as aciclovir?

  • You can give your child medicines that contain paracetamol or ibuprofen, unless your doctor has told you not to.
  • Aciclovir should not be taken with some medicines that you get on prescription. Tell your doctor and pharmacist about any other medicines your child is taking before giving aciclovir.
  • Check with your doctor or pharmacist before giving any other medicines to your child. This includes herbal or complementary medicines.

Is there anything else I need to know about aciclovir?

  • It is important that your child takes the whole course of this medicine, which is usually for 5 days but may be much longer. Your doctor will tell you how long it needs to be taken for. If you stop early, the infection may come back, and may then be harder to treat.
  • Children are sometimes sick (vomit) or get diarrhoea when taking antiviral medicines. Encourage them to drink water to replace the fluid they have lost, and consult your doctor if they are not drinking or are unwell.
  • Do not give your child any medicine to stop the diarrhoea unless your doctor has told you to, as this can make things worse.

General advice about medicines

  • Try to give medicines at about the same times each day, to help you remember.
  • 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.
  • 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.

If you think someone else may have taken the medicine by accident, contact your doctor straight away.

  • Give any unused liquid medicine to your pharmacist to dispose of, or wash it down the sink. Do not keep it for future infections.

Where I should 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 doctor, pharmacist or nurse will be able to give you more information about aciclovir and about other medicines used to treat viral infections.

You can also get useful information from: 
Publication date: 
11/05/2012

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