Erythromycin

Erythromycin is an antibiotic. It can be taken by people who are allergic to penicillin.

Space your doses out evenly over the day and complete the full course of this antibiotic, even if you feel your infection has cleared up.

The most common side-effects are feeling sick and abdominal discomfort. These are usually mild.

Type of medicine A macrolide antibiotic
Used for Infections (in adults and children), and for skin problems such as acne and rosacea
Also called Brand names: Erymax®; Erythrocin®; Erythroped®; Erythrolar®; Tiloryth®
Generic names: erythromycin stearate; erythromycin ethyl succinate
Available as Tablets, capsules, and oral liquid medicine

Erythromycin is prescribed to treat acute bacterial infections, such as respiratory infections, urine infections, skin infections, and mouth infections. It can be taken by adults and children. It works by killing the bacteria causing the infection. It is also prescribed for some longer-term skin conditions such as acne and rosacea.

Erythromycin is also available as an ingredient in some skin preparations used to treat acne - see the separate medicine leaflet called Erythromycin skin solution for acne for more information about this.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking erythromycin it is important that your doctor or pharmacist knows:

  • If you are pregnant or breast-feeding. (Although erythromycin is not known to be harmful to an unborn baby, you should let your doctor know if you think you are pregnant.)
  • If you have any problems with your liver or kidneys.
  • If you know you have an unusual heart rhythm.
  • If you have a muscle disorder called myasthenia gravis.
  • If you have a rare inherited blood disorder called porphyria.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • If you have ever had an allergic reaction to a medicine.
  • Before you start taking this antibiotic, read the manufacturer's printed information leaflet from inside the pack. The leaflet will give you more information about it and a full list of side-effects which you may experience from taking it.
  • Take erythromycin exactly as your doctor tells you to. It is usually prescribed four times daily, although one or two doses daily may be sufficient for some conditions. Your doctor or pharmacist will tell you which dose is right for you (or for your child). Your dose will also be on the label of the pack to remind you. Space the doses out evenly during the day.
  • Swallow erythromycin tablets and capsules whole, with a drink of water. Do not chew them. You may take erythromycin before or after food.
  • When erythromycin is prescribed for a child, the dose depends upon the child's weight. Make sure you read the label carefully so that you measure out the correct amount of medicine.
  • Even if you feel your infection has cleared up, keep taking this antibiotic until the course is finished unless your doctor tells you otherwise. This is to prevent the infection from coming back. A course of treatment for an acute infection often lasts around 5-14 days. It may last for longer than this if you are taking erythromycin for chronic prostatitis, acne or rosacea - in these cases it is quite normal for your treatment to continue for several weeks or months. If you still feel unwell after finishing your course of treatment, make another appointment to see your doctor for further advice.
  • If you forget to take a dose, take one as soon as you remember. Try to take the correct number of doses each day, but do not take two doses at the same time to make up for a forgotten one.
  • If you buy any medicines, check with a pharmacist that they are safe to take with erythromycin. If you regularly take an indigestion remedy, make sure your doctor knows about this, as some brands of erythromycin should not be taken at the same time as antacids. Check the label on your pack of erythromycin for more information about this.
  • Some people develop thrush (redness and itchiness in the mouth or vagina) after taking a course of antibiotics. If this happens to you, speak with your doctor or pharmacist for advice.
  • If you are using combined oral 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 about this, speak with your doctor or pharmacist.
  • 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.

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 erythromycin side-effects What can I do if I experience this?
Feeling or being sick, abdominal discomfort Stick to simple meals - avoid rich or spicy food. Taking your doses after food may help
Diarrhoea Drink plenty of water to replace lost fluids. If the diarrhoea continues or is severe, speak with your doctor

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

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.
  • If you have been given liquid medicine, it will have been made up by the pharmacy and it lasts for a limited number of days only. Check the expiry date on the bottle and do not use it after this date.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Further reading & references

  • Manufacturer's PIL, Erymax® Capsules; Cephalon (UK) Limited, The electronic Medicines Compendium. Dated October 2010.
  • British National Formulary; 65th Edition (Mar 2013) British Medical Association and Royal Pharmaceutical Society of Great Britain, London

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Prof Cathy Jackson
Last Checked:
09/07/2013
Document ID:
3340 (v25)
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