How does erythromycin work?
Erythromycin is part of 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.
Tell your doctor if you do not start feeling better after taking erythromycin for 3 days. Also tell them if you start to feel worse at any time.
Skin problems such as acne and rosacea usually take 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.
How does erythromycin compare with other antibiotics?
There are other macrolide antibiotics that work in the same way as erythromycin. They include clarithromycin and azithromycin.
You’ll usually take erythromycin 2 or 4 times a day. For clarithromycin it’s twice a day and for azithromycin it's once a day.
Clarithromycin and azithromycin are less likely to cause diarrhoea than erythromycin.
All macrolides can be used to treat chest and skin infections.
Azithromycin can also be used to treat sexually transmitted infections.
Clarithromycin can also be used to treat Helicobacter pylori, a bacteria that can cause stomach ulcers.
Erythromycin and other macrolide antibiotics kill similar types of bacteria to penicillin antibiotics, such as amoxicillin.
Some people are allergic to penicillin antibiotics – they can take erythromycin instead.
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 pharmacist or doctor for advice if this happens to you.
Will it affect my contraception ?
Erythromycin does not stop any type of contraception from working, including the combined pill, progestogen-only pill and emergency contraception.
However, if erythromycin makes you vomit or have severe diarrhoea for more than 24 hours, your contraceptive pill may not protect you from pregnancy. Check the pill packet to find out what to do.
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Can I drive or ride a bike?
Yes, erythromycin should not affect you being able to drive or cycle.
Can I drink alcohol while taking erythromycin?
It’s best to stop drinking alcohol or limit how much you drink while you're taking erythromycin.
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.
Is there any food or drink I need to avoid?
Do not eat grapefruit or drink grapefruit juice while you're taking erythromycin.
Grapefruit can increase the amount of erythromycin in your body, which means you're more likely to have side effects.