Penicillin V for bacterial infections

This leaflet is about the use of the antibiotic penicillin V for the treatment of bacterial infections.

This leaflet has been written specifically 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.

If your child has ever had a reaction to any antibiotic, check with your doctor that your child can have penicllin V before giving it.

Name of drug

Penicillin V, also known as phenoxymethylpenicillin

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

It is important that your child takes this medicine in the way that your doctor has told you to so that it kills the harmful bacteria and gets rid of their infection.

What is penicllin V available as?

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

When should I give penicllin V?

Penicillin V is usually given four times a day. This is usually first thing in the morning (before breakfast), at about midday (before lunch), late in the afternoon (before tea) and at bedtime. Ideally, these times should be at least 3 hours apart. Sometimes Penicillin V is given twice a day to prevent infections.

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.

How should I give it?

This medicine works best when the stomach is empty, so try to give it to your child ½–1 hour before they eat. However, if your child has an upset stomach, you can give it with a small amount of food.

Penicillin V for bacterial infectionsTablets should be swallowed with a glass of water, milk or juice. Your child should not chew the tablets.

Penicillin V for bacterial infectionsLiquid 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. You can also dilute the right amount of medicine (measured with a spoon) in a small amount of water or milk. Make sure your child takes it all straight away.

It is important that you give your child the whole dose each time.

When should the medicine start working?

Your child should start to get better after taking the medicine for 2 days. It is important that they take the whole course of the medicine that has been prescribed. Do not stop early.

What if my child is sick (vomits)?

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

What if I forget to give it?

  • If you miss a dose, wait until the next normal dose. Do not give the missed dose.
  • If you forget to give the dose before your child has eaten, but remember during the meal, give them the dose straight after finishing the meal.

Never give a double dose of penicillin V.

What if I give too much?

Penicillin V is normally a safe drug. It is unlikely to cause any problems if you give an extra dose by mistake. If you think you may have given your child too much penicillin V, contact your doctor or NHS Direct (0845 4647 in England and Wales; 08454 24 24 24 in Scotland). Have the medicine container or packet 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 are rare with penicillin V and do not usually last for long. They will get better after a day or two as your child’s body gets used to the medicine, and should go away when the treatment course is finished.

Side-effects you must do something about

If your child gets a skin rash or itching, is short of breath or is wheezing, or their face, lips or tongue start to swell, they may be allergic to penicillin V. Take your child to hospital or call an ambulance straight away.

Other side-effects you need to know about
  • Some children get diarrhoea, stomach pains and may feel sick or be sick (vomit) when they first start taking penicillin V. The box overleaf gives advice on what to do.
  • Contact your doctor if your child has diarrhoea that goes on for more than 4 days or if it is severe and watery, or contains blood.
  • 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. If you think your child may have thrush, contact your doctor or pharmacist for advice.

Important things to know about taking antibiotics

  • It is important that your child completes the course of antibiotic. This means that they must take the medicine for the number of days that the doctor has told you to, or until all of the medicine has been taken. If you stop giving the antibiotic too soon, the bacteria that are left will start to multiply again, and may cause another infection. There is also a risk that these bacteria will be ‘resistant’ to the first antibiotic. This means that it might not work next time, and your child might need a different antibiotic.
  • Children are sometimes sick (vomit) or get diarrhoea when taking antibiotics. Encourage them to drink water to replace the fluid they have lost.
  • Do not give your child any medicine to stop the diarrhoea unless your doctor has told you to, as this can make things worse.
  • Try to give the medicine at about the same times each day, to help you remember, and to make sure that there is the right amount of medicine in your child’s body to kill the bacteria.
  • Only give this medicine to your child for their current infection.
  • Never save medicine for future illnesses. Throw away any unused medicine or return it to the pharmacist.
  • Only give the antibiotic to the child for whom it was prescribed. Never give it to anyone else, even if their condition appears to be the same, as this could do harm.

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

  • Antibiotics only kill bacteria; they do not kill viruses. This means that they do not work against colds, sore throats, flu or other infections that are caused by viruses. Your doctor will not prescribe antibiotics for these illnesses.

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 common drugs that you get on prescription. If your child is taking any other medicines, tell your doctor and pharmacist.
  • 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 this medicine?

Your child should not have penicillin V if he or she has ever shown any signs of allergy to any penicillin antibiotic.

  • Your doctor will only have prescribed penicillin V for a sore throat if he or she believes that it is caused by a bacteria called Streptococcus. Most sore throats are caused by viruses, however, which are not killed by antibiotics.

Where I should keep this medicine?

  • Keep this medicine in a cupboard, away from heat, direct sunlight and excess moisture (do not keep it in the bathroom).

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 child’s doctor, pharmacist or nurse will be able to give you more information about penicillin V and about other medicines used to treat infections.


You can also get useful information from:


Publication Date

9/12/2011

Copyright Disclaimer

Version 1.2, December 2009 (November 2011). © NPPG, RCPCH and WellChild 2011, all rights reserved.

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, www.medicinesforchildren.org.uk
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.