Ampicillin for bacterial infection

This leaflet is about the use of ampicillin for bacterial infection in children.

Information Standard quality markThis 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.

Your child should not take ampicillin if they are allergic to penicillin. If your child has ever reacted to a medicine, tell your doctor before giving ampicillin.

Name of drug

Ampicillin
Brand name: Penbritin®

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 all the bacteria and gets rid of the infection.

What is ampicillin available as?

  • Capsules: 250 mg, 500 mg (grey/red)
  • Liquid medicine (suspension): 125 mg in 5 mL (apricot, caramel and peppermint flavours); may contain a small amount of sugar

When should I give ampicillin?

Ampicillin is usually given four times a day. This is usually first thing in the morning, at lunchtime, late afternoon and at bedtime. Ideally, these times are at least 4 hours apart.
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 ampicillin (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?

Capsules should be swallowed whole with a glass of water, squash or milk (but not juice). Your child should not chew the capsule. 

Liquid medicine: Measure out the right amount using a medicine spoon or oral syringe. 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?

The medicine will start working straight away and your child should start to get better after taking the medicine for 2 days. It is important that they take the whole course of 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 ampicillin, give them the same dose again.
  • If your child is sick more than 30 minutes after having a dose of ampicillin, 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.

What if I give too much?

Ampicillin is generally a safe drug, and is unlikely to cause harm if your child has an extra dose by mistake.
If you are worried you may have given your child too much, contact your doctor or NHS Direct ((0845 4647 in England and Wales; 08454 24 24 24 in Scotland). Have the medicine 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 that you must do something about

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

If your child gets a lumpy red rash, they may have another infection such as glandular fever. Take them to your doctor.

Other side-effects you need to know about

  • Your child may get some stomach pains, diarrhoea, vomiting or feel sick when they first start taking ampicillin. These side-effects are usually mild and improve with time. Giving the medicine just before some food may help. The box overleaf gives advice on what to do about diarrhoea.
  • If child has diarrhoea that lasts for longer than 4 days, or it has blood in it, contact your doctor.
  • 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 antibiotics. This means that they must take the medicine for the number of days that the doctor has told you, or until all the medicine has been taken. Your child will probably start to feel better soon after starting to take the antibiotic. However, it takes a few days for the antibiotic to kill all the bacteria. 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 stronger antibiotic.

  • Children are sometimes sick (vomit) or get diarrhoea when taking antibiotics. Encourage them to drink water to replace the fluid they have lost. You can also buy oral rehydration fluid from your pharmacist.
  • 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.
  • 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.

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

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

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

Your child should not have ampicillin if they are allergic to penicillin antibiotics.
If your child has ever had an allergic reaction or other reaction to any medicine, tell your doctor. If you have forgotten to tell your doctor, check with the doctor or pharmacist before giving ampicillin to your child.

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 it.
  • 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 ampicillin and about other medicines used to treat bacterial infections.


You can also get useful information from:


Publication Date

17/11/2011

Copyright Disclaimer

Version 1.2, March 2011. © NPPG, RCPCH and WellChild 2011, all rights reserved. Reviewed by: March 2013.

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.