Penicillin V for prevention of pneumococcal 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.

Penicillin V helps prevent life-threatening infections

  • Children with sickle cell disease and those without a spleen have difficulty fighting infections, particularly pneumococcal infection, and they risk becoming seriously ill. By giving Penicillin V regularly, you can protect your child from these infections.
  • The Penicillin V helps your child to fight infection. It does not weaken their immune system.
  • You must give the Penicillin V every day to protect your child, even if they seem well.
  • If your child is allergic to any antibiotics, tell your doctor before starting Penicillin V.

Name of medicine

Penicillin V (also known as phenoxymethylpenicillin)

Why is it important for my child to take Penicillin V?

The spleen is an important organ that helps the body to fight infections caused by bacteria and other germs. Sometimes a child’s spleen has to be removed. In others, including those with sickle cell anaemia, the spleen doesn’t work properly. This makes it harder for the body to fight bacteria, and children risk getting serious infections.

Giving penicillin V regularly will help to kill pneumococcal bacteria (which cause serious infections such as pneumonia, septicaemia and meningitis). You must continue to give it every day, even if your child seems well, as infections can develop slowly and without many symptoms.

What is Penicillin V available as?

  • Tablets: 250 mg
  • Liquid medicine: 125 mg or 250 mg in 5 mL

These may contain a small amount of sugar. Sugar-free preparations are also available.

When should I give Penicillin V

The Penicillin V is usually given twice each day. Give one dose in the morning and one in the evening. Ideally these times are 10–12 hours apart. For example, this could be between 7am and 8am and between 7pm and 8pm.

Give the medicine 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.

How much should I give?

Your doctor will work out the amount of Penicillin V (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.

When Penicillin V is given to prevent infection, a lower dose is used than when treating an infection.

How should I give Penicillin V?


  • Tablets should be swallowed with a glass of water, squash or juice. Your child should not chew the tablet.

Liquid medicine

  • Shake the medicine well.
  • Measure out the right amount using an oral syringe or a medicine spoon. You can get these from your pharmacist. Do not use a kitchen teaspoon as it will not give the right amount.

This medicine works best when the stomach is empty, so try to give it to your child about an hour before they eat. However, if your child has an upset stomach, you can give it with a small amount of food.

When should the medicine start working?

The medicine will start to protect your child from infection when they have been taking it for a few days. However, you won’t see any difference in your child.

You must continue to give Penicillin V to your child every day, even if they seem well, so that they are protected from infection.

What if my child is sick (vomits)?

If your child is sick and has a fever (a temperature higher than 38°C) or seems unwell, take them to a doctor, in case they are developing an infection.

What if I forget to give it?

If you usually give it twice a day: If you remember up to 4 hours after you should have given a dose, give your child the missed dose. For example, if you usually give a dose at about 7am, you can give the missed dose at any time up to 11am. If you remember after that time, do not give the missed dose. Give the next dose as usual.

What if I give too much?

You are unlikely to cause harm if you give an extra dose of Penicillin V by mistake. If you are concerned that you may have given too much, 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 or, in this case, to keep them well. Sometimes medicines have other effects that we don’t want (side-effects). Most children who take penicillin V to prevent infection do not have any 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 Penicillin V. Take your child to hospital or phone for an ambulance straight away.

If your child has diarrhoea and vomiting, contact your doctor, as they could become very unwell.

Other side-effects you need to know about

  • You may see white patches inside your child’s mouth and throat, and girls may get itching or soreness around the vagina. This is caused by a fungal infection called thrush. Contact your doctor or pharmacist for advice.

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 Penicillin V?

  • You can give your child medicines that contain paracetamol or ibuprofen, unless your doctor has told you not to.
  • Penicillin V should not be taken with some medicines. Tell your doctor or pharmacist about any other medicines your child is taking before giving Penicillin V.

Check with your doctor or pharmacist before giving any other medicines to your child. This includes herbal and complementary medicines.

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

Never stop giving Penicillin V without telling your doctor, even if you think it isn’t doing anything.

  • Giving antibiotics every day for prevention of illness makes a big difference to the health of children with sickle cell disease and those with asplenia.
  • Giving antibiotics every day does not weaken your child’s immune system.
  • Penicillin V provides protection against pneumococcal bacteria, which can cause serious infections in children with sickle cell disease or asplenia. It does not provide protection against other types of infection.
  • Your doctor may have recommended that your child has a vaccination to help prevent pneumococcal infection. However, these vaccines do not protect against all types of pneumococcal bacteria so your child will still need to take penicillin V.
  • If your child develops an infection, your doctor may prescribe a short course of antibiotics to treat this. They will probably tell you to stop giving the penicillin V during this time. You should start giving the penicillin V again on the day after the treatment antibiotics are finished.

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.
  • Make sure that you always have enough medicine. Order a new prescription at least 2 weeks before you will run out.
  • 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.

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

Where should I keep this medicine?

  • Keep the medicine in a cupboard, away from heat and direct sunlight.
  • You may need to keep liquid medicine in the fridge – check the instructions on the bottle. Make sure the medicine does not freeze.
  • 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 Penicillin V and about other ways to protect a child with sickle cell disease or asplenia from infection.

England: NHS 111

Tel 111

Scotland: NHS 24

Northern Ireland: NI Direct

Wales: NHS 111 Wales

Sickle Cell Society

Copyright disclaimer

Version [2]. © NPPG, RCPCH and WellChild, all rights reserved. Review by March 2022.

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.