• Penicillin V (sometimes called phenoxymethylpenicillin) is an antibiotic used to treat bacterial infections.
  • The most common side-effects are diarrhoea and skin rashes.
  • If you experience difficulty breathing after starting to take this medicine, do not take any more doses and see a doctor immediately.

About penicillin V

Type of medicine Penicillin antibiotic
Used for Bacterial infections
Also called Phenoxymethylpenicillin
Available as Tablets and oral liquid

Penicillin V is used to treat bacterial infections such as infections of the chest and throat. It works by killing or stopping the growth of bacteria that cause the infection. Penicillin V can also be used to prevent infections from occurring.

Before taking penicillin V

Before taking penicillin V make sure your doctor or pharmacist knows:

  • If you are pregnant or breast-feeding.
  • If you are taking other medicines, including those available to buy without a prescription, herbal and complementary medicines.
  • If you have ever had an allergic reaction to this or any other medicine. It is particularly important that you tell your doctor if you are allergic to any antibiotics.

How to take penicillin V

  • Before beginning treatment, read the manufacturer's printed information leaflet from inside the pack.
  • Take penicillin V exactly as your doctor has told you.
  • Penicillin V is usually taken every six hours. Space the doses evenly throughout the day.
  • Keep taking this antibiotic until the course is finished unless you are told to stop. This is to prevent your infection from coming back.
  • Take penicillin V when your stomach is empty. This means an hour before food or 2 hours after food.
  • Try not to miss any doses. If you do forget a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a forgotten dose.

Getting the most from your treatment

  • Some people develop thrush (redness and itching in the mouth or vagina) after taking a course of antibiotics. If you think you have thrush speak with your doctor or pharmacist for advice.
  • If you are using oral combined hormonal contraception (the 'pill'), additional contraceptive precautions such as condoms are not required during a course of this antibiotic unless you are sick or have diarrhoea. If you need further advice, speak with your doctor or pharmacist.
  • If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking penicillin V.
  • This antibiotic may stop the oral typhoid vaccine from working. If you are having any vaccinations, make sure the person treating you knows that you are taking this medicine.
  • If you still feel unwell after completing your course of penicillin V, make another appointment to see your doctor.

Can penicillin V cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common side-effects What can I do if I experience this
Diarrhoea Drink plenty of water to replace lost fluids. If the diarrhoea is severe or lasts for more than 24 hours, see your doctor
Stomach ache Eat little and often and stick to simple or bland foods
Thrush, skin rash and itching Speak with your doctor or pharmacist for advice

Important: If you experience any of the following symptoms, stop taking penicillin V and contact your doctor for advice straight away:

  • Swelling of your tongue, mouth, or face, or any problems with your breathing.
  • A severe itchy skin rash.
  • Fever with pain in your joints.
  • Severe diarrhoea.

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

How to store penicillin V

  • Keep all medicines out of the reach and sight of children.
  • Store penicillin V tablets in a cool, dry place, away from direct heat and light.
  • Store penicillin V oral liquid in a refrigerator and do not use it after the expiry date shown on the label.