Erythromycin is an antibiotic.
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.
- 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 sick, 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
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.
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, but it may increase the chance of temporary side effects, such as hearing loss, feeling sick, vomiting, and diarrhoea.
Talk to your pharmacist or doctor if you're worried, or you or your child accidentally take more than one extra dose.
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
- stomach cramps
- 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 (warning signs of pancreas problems)
- yellowing of the skin and/or eyes, or pale poo with dark pee (warning signs of liver or gallbladder problems)
- 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
- tightness in the chest or throat
- having trouble breathing or talking
- unusual hoarseness
- 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 – 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 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 and supplements.
How does erythromycin work?
When will I feel better?
Can I drink alcohol with it?
Will it give me thrush?
Will it stop my contraception working?
Will it reduce my fertility?
What if I don't get better?
Is there any food or drink I need to avoid?