Erythromycin

About erythromycin

Erythromycin is an antibiotic.

It's widely used to treat chest infections, such as pneumonia, skin problems such as acne and rosacea, dental abscesses, and sexually transmitted infections.

Erythromycin is used in children, often to treat ear infections or chest infections.

The medicine is available on prescription as tablets, capsules, or a liquid that you drink.

It's also available as a skin solution to treat skin infections like acne. It can be given by injection, but this is usually only done in hospital.

Key facts

Take erythromycin 2 or 4 times a day as prescribed by your doctor.
For most infections, you should feel better within a few days.
For skin conditions like acne and rosacea, it may take a couple of months before you see an improvement.
The most common side effects of erythromycin are feeling or being sick (nausea or vomiting), stomach cramps, and diarrhoea.
Drinking alcohol with erythromycin may slightly reduce or delay the medicine's benefits.
Erythromcyin is also called by the brand names Erythrocin, Erythrolar, Erymax, Tiloryth, Rommix, Erythroped A, and Erythroped.

Who can and can't take erythromycin

Erythromycin can be taken by adults, including pregnant and breastfeeding women.

Erythromycin can be taken by children.

Erythromycin isn't suitable for certain people. To make sure erythromycin is safe for you, tell your doctor if you have:

had an allergic reaction to erythromycin or other antibiotics in the past
porphyria (a rare, inherited blood disorder)
liver or kidney problems
had diarrhoea when you've taken antibiotics before
fast, pounding or irregular heartbeats
a sexually transmitted infection called syphilis and you're pregnant - erythromycin alone may not be able to prevent your baby getting the infection
myasthenia gravis - erythromycin can worsen the symptoms of this muscle-weakening illness

How and when to take it

The usual dose of erythromycin is 250mg to 1,000mg taken 4 times a day. Sometimes it's taken twice a day. The dose may be lower for children.

Try to space the doses evenly throughout the day - for example, first thing in the morning, at about midday, late in the afternoon, and at bedtime.

Generally, it's better to take erythromycin after food so it doesn't upset your stomach.

Carry on taking this medicine until the course is completed, even if you feel better. If you stop your treatment early, your infection could come back.

How to take it

Swallow erythromycin tablets or capsules whole with a drink of water. Don't chew or break them.

There's a liquid erythromycin for children and people who find it difficult to swallow tablets.

If you or your child are taking erythromycin as a liquid, it'll usually be made up for you by your pharmacist. The medicine will come with a syringe or spoon to help you take the right amount. If you don't have a syringe or spoon, ask your pharmacist for one.

What if I forget to take it?

If you forget to take a dose, take it as soon as you remember, unless it's nearly time for your next dose. In this case, just leave out the missed dose and take your next dose as normal.

Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.

If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

What if I take too much?

Try to take the correct number of doses each day, leaving at least 4 hours between doses.

Taking an extra dose of erythromycin by accident is unlikely to harm you or your child. It may, however, increase the chance of temporary side effects, such as hearing loss, feeling or being sick, and diarrhoea.

Talk to your pharmacist or doctor if you're worried, or if you or your child accidentally take more than 1 extra dose.

Side effects

Like all medicines, erythromycin can cause side effects, although not everyone gets them.

Common side effects

These common side effects of erythromycin happen in more than 1 in 100 people. Keep taking the medicine, but talk to your doctor or pharmacist if these side effects bother you or don’t go away:

feeling sick (nausea)
being sick (vomiting)
stomach cramps
diarrhoea
loss of appetite
bloating and indigestion

Serious side effects

Serious side effects are rare and happen in less than 1 in 1,000 people.

Tell a doctor straight away if you get:

chest pains or your heart is beating abnormally
skin rash
severe stomach pain - this can be a sign of pancreas problems
yellowing of the skin and/or eyes, or pale poo with dark pee - these can be signs of liver or gallbladder problems
seizures
hallucinations (seeing or hearing things that aren't there)
ringing in the ears, temporary hearing loss, or feeling unsteady on your feet
a temperature of 38C or above
poor appetite
feeling generally unwell

Serious allergic reaction

In rare cases, it’s possible to have a serious allergic reaction to erythromycin.

A serious allergic reaction is an emergency. Contact a doctor straight away if you think you or someone around you is having a serious allergic reaction.

The warning signs of a serious allergic reaction are:

getting a skin rash that may include itchy, red, swollen, blistered or peeling skin
wheezing
tightness in the chest or throat
having trouble breathing or talking
swelling of the mouth, face, lips, tongue, or throat

These are not all the side effects of erythromycin. For a full list see the leaflet inside your medicines packet.

You can report any suspected side effect to the UK safety scheme.

How to cope with side effects

What to do about:

feeling sick (nausea) - stick to simple meals and don't eat rich or spicy food while you're taking this medicine. It might help to take your erythromycin after you've had a meal or snack.
diarrhoea and being sick (vomiting) - drink plenty of water or other fluids if you have diarrhoea or you're being sick. It may also help to take oral rehydration solutions you can buy from a pharmacy to stop dehydration. Don't take any other medicines to treat diarrhoea or vomiting without speaking to a pharmacist or doctor

Pregnancy and breastfeeding

It's usually safe to take erythromycin during pregnancy and while breastfeeding.

For safety, tell your doctor if you're trying to get pregnant, are already pregnant or if you're breastfeeding.

Cautions with other medicines

There are some medicines that don't mix well with erythromycin.

Tell your doctor if you're taking these medicines before you start erythromycin:

antihistamine medicines, such as astemizole, terfenadine or mizolastine
an anti-sickness medicine called domperidone
medicines for mental health problems called pimozide and amisulpride
migraine medicines called ergotamine and dihrydroergotamine
a cholesterol-lowering medicine called simvastatin
a bladder weakness medicine called tolterodine

Mixing erythromycin with herbal remedies and supplements

There are no known problems with taking herbal remedies or supplements alongside erythromycin.

However, for safety, tell your doctor or pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.

Common questions

How does erythromycin work?

Erythromycin is from a group of medicines called macrolide antibiotics. Macrolide antibiotics work by killing the bacteria causing the infection.

When will I feel better?

For most infections, you should feel better within a few days.

For skin problems such as acne and rosacea, expect to take the medicine for at least 2 months before you see much improvement.

It's very important that you keep taking erythromycin until your course is finished. Do this even if you feel better. It will help to stop the infection coming back.

Can I drink alcohol with it?

There's no specific warning to stop drinking alcohol while taking erythromycin, but there's some evidence that alcohol may slow down or delay the medicine working. You might want to stop drinking alcohol or limit how much you drink while you're taking erythromycin.

Will it give me thrush?

Some people get a fungal infection called thrush after taking a course of antibiotics like erythromycin. It happens because antibiotics kill the normal harmless bacteria that help to protect you against thrush.

Ask your doctor or pharmacist for advice if this happens to you.

Will it stop my contraception working?

Erythromycin doesn't stop contraceptive pills working.

However, if erythromycin makes you vomit or have severe diarrhoea (6 to 8 watery poos in 24 hours) for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Look on the pill packet to find out what to do.

Will it reduce my fertility?

There's been research suggesting that erythromycin may reduce male fertility by reducing and slowing down sperm. The evidence is weak, though, and this link isn't proven. Talk to your doctor if you're concerned.

What if I don't get better?

Tell your doctor if you don't start feeling better after taking erythromycin for 3 days. Also tell them if, at any time, you start to feel worse.

If you're taking erythromycin for a skin infection, it may take several weeks to see an improvement.

Is there any food or drink I need to avoid?

Don't eat grapefruit or drink grapefruit juice while you're taking erythromycin.

Grapefruit can increase the amount of erythromycin in your body and mean you're more likely to have side effects.