Erythromycin is a prescription-only antibiotic in the Macrolide family. This medication works by stopping the bacteria in your body that is responsible for an infection from producing proteins. More information

A doctor will review your order and write you a prescription, if appropriate. This prescription is then forwarded to a pharmacy. The pharmacy will have your medicine delivered to you within one to three working days. Read more about this process here.

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Erythromycin is a kind of macrolide antibiotic that works to prevent bacteria from multiplying. The medication can be used for the treatment of various infections but is often given for chest infections. Erythromycin is a prescription only medication.  

What is Erythromycin ? 

Erythromycin is a prescription-only antibiotic in the Macrolide family. This medication works by stopping the bacteria in your body that is responsible for an infection from producing proteins. These proteins are crucial for the bacteria to grow and thrive, meaning that they quickly die out.  

Erythromycin can be provided in various forms, including as tablets, capsules, or in an oral suspension liquid. In all forms, Erythromycin is only available with a prescription from a doctor and should not be used to treat viral infections. Erythromycin only works on bacterial infections and will not treat viral issues like the flu or common cold.  

When is Erythromycin used? 

Erythromycin is used for the treatment of a range of bacterial infections. Your doctor will assess whether this treatment is right for you or not during your assessment. Erythromycin is widely used for the treatment of chest infections, and issues like pneumonia. However, it may also be helpful for skin problems like rosacea and acne, as well as dental infections.  

Erythromycin is rarely used for the treatment of sexually transmitted infections. Additionally, it can help with the treatment of children’s chest infections and ear infections. The medicine is available on prescription only and can sometimes be provided in a skin solution that treats issues like acne.  

In very rare cases, Erythromycin can be provided in an intravenous form, but this will only be provided in a hospital environment.  

How do you use Erythromycin? 

Erythromycin should be taken by mouth according to the directions provided by your doctor. Erythromycin is usually taken before a meal or 2 hours after a meal, as it works best when you use it on an empty stomach. You should not crush the medication before taking it, you will need to swallow it completely whole.  

If nausea occurs when taking Erythromycin¸ your doctor may recommend taking it with milk or food anyway, to reduce your risk of vomiting. Remember to read the patient leaflet that is provided with this medication before you begin taking it. Reading the leaflet will provide you with information on how you can avoid issues like side effects. For the best effect, you should take Erythromycin at evenly spaced times. Remember to take it at the same time each day for the best outcomes. 

If you are using Erythromycin to treat an infection it is important to continue taking it for the full length of the course prescribed to you. Stopping use of an antibiotic before you are recommended to do so could mean that your infection comes back, and that it may even be resistant to the antibiotic in the future. If you are taking Erythromycin for the prevention of a bacterial infection, take it exactly as your doctor recommends. Do not stop using Erythromycin without your doctor’s approval.  

What dosages are there? 

Erythromycin will be given to you in a specific dose depending on your response to treatment and the condition that you are treating. You will take a smaller dose of Erythromycin if you are using it for the prevention of bacterial infections.  

The typical dose for the treatment of an acute infection is 2 grams of Erythromycin spread out over the course of a day. Your doctor may prescribe alternative dosages for children and people who have a higher risk of side effects with this drug. You should always follow the prescription exactly and should not take more or less of this substance than prescribed by a doctor.  

What are the side effects of Erythromycin ? 

Erythromycin can sometimes cause unintended side effects alongside its intended effects. The most common side effects are usually mild and will dissipate on their own. These include vomiting, nausea, diarrhea, and stomach pain. You may also experience some cramping when taking Erythromycin.  

You should speak to a doctor or pharmacist immediately if any side effects when using Erythromycin persist or worsen. Speak to a medical professional immediately if you have any serious side effects with this substance, including: 

  • Signs of live problems, such as yellowing skin, eyes, or dark urine; 
  • Severe abdominal or stomach pain; 
  • Unusual tiredness or muscle weakness; 
  • Blurred vision; 
  • Slurred speech; 
  • Hearing loss; 
  • Vision loss; 
  • Rash of any kind 

Get medical help immediately if you experience severe dizziness or irregular heartbeat. You should note that this medication can sometimes cause Clostridium difficile diarrhea caused by a resistant bacteria. This condition can occur during the course of your treatment, or after your treatment has stopped. Do not use opioid medications or anti-diarrhea medications if you have those symptoms.  

Use of Erythromycin for an extended period of time can cause a new case of yeast infection or thrush. Contact your doctor if you notice any new symptoms when taking Erythromycin. 

It is unlikely that you will experience a severe allergic reaction when taking Erythromycin. However you should seek medical attention immediately if you notice any symptoms of a severe allergic reaction, including, itching and swelling around the throat, tongue, and face, as well as trouble breathing.  

Please not that there may be other side effects to taking Erythromycin that are not listed here. Seek medical advice if you notice any other side effects when using Erythromycin.  

When shouldn’t you use Erythromycin ? 

Erythromycin can be dangerous when it is taken for a reason that it is not intended, or by someone who is predisposed to have negative reactions to this medication. To ensure that you are getting the right treatment for your needs, it’s important for you to discuss all of your medical history with your doctor or consultant as truthfully as possible.  

Tell your consultant or doctor if you are allergic to Erythromycin or any similar antibiotics. You should also make your consultant or doctor aware if you have any other allergies too. This substance can sometimes include inactive ingredients that cause allergic reactions and other problems.  

Before you take Erythromycin tell your doctor immediately if you have a medical history of liver disease or kidney disease, or any kind of muscle disease. In rare cases, Erythromycin can sometimes cause a condition that affects the rhythm of your heart, causing severe side effects that need immediate medical attention. Your risk of this condition could be higher if you have a family history of heart disruptions or heart failure. You could also have a higher risk of heart problems if you take medications that are also likely to cause changes in your heart rhythm. 

Lower levels of magnesium or potassium in your blood could also increase your risk of problems with your heart rhythm. This issue may become more likely if you are using medications like diuretics. Talk to your doctor about using Erythromycin properly.  

Erythromycin can cause live bacterial vaccinations to work improperly. You should not have any immunizations or vaccinations without your doctor’s approval. Before you have any procedures done, it is important to tell your medical professional about any drugs that you’re taking.  

Some Erythromycin can contain sodium. If you are on a diet that restricts you from using salt, or you have a condition that could be worsened by an increased sodium intake, speak to your consultant or doctor about this before you take Erythromycin.  

It may not be suitable for you to use Erythromycin if you are pregnant or breastfeeding. Erythromycin is usually only recommended for use in pregnant women when it is deemed absolutely necessary. Talk to your doctor about your options and you may be recommended to take a different kind of medication. Erythromycin can also pass through into breast milk, so you may need to stop breastfeeding when you are using this medication.  

Does Erythromycin interact with other medications? 

Interactions between medications can change how your medications work and may also increase your risk of suffering from side effects. It is important to speak to your doctor or consultant about any medications that you are using alongside Erythromycin before you begin taking it. Make sure that your consultant or doctor is aware of all the substances that you are taking alongside Erythromycin, including prescription and nonprescription drugs. You should also mention any herbal remedies or recreational drugs.  

One substance that may interact negatively with Erythromycin is digoxin. There are also a number of drugs alongside Erythromycin that can affect your heart rhythm. Some of these include cisapride, amiodarone, and quinidine. Make sure that none of the medications you are using put you at an increased risk of QT prolongation when using Erythromycin. 

Some medications can affect the way that Erythromycin is removed from the body, which could increase your chances of negative side effects. Examples include some calcium channel blockers, anti seizure medications, and also some azole antifungal medications.  

Erythromycin may also slow the way that other drugs are removed from your body, which could affect how they work. The examples of affected drugs include colchicine, bromocriptine, and various benzodiazepines. Certain drugs to treat ED can also be influenced by Erythromycin.  

This medication can sometimes interfere with a certain lab tests, causing false test results. Make sure that all medical professionals are aware of your medications.  

Where can you buy Erythromycin? 

Erythromycin is available to purchase both offline and online through a reliable pharmacy. You can purchase Erythromycin with a prescription.  

Can I get Erythromycin without a prescription? 

Erythromycin is not available without a prescription.   


Mayo Clinic, Erythromycin (Oral Route), Accessed 28th of February 2020, retrieved from:, Erythromycin Tablets BP 250 mg, Accessed 28th of February 2020, retrieved from: 

Nice, BNF, ERYTHROMYCIN, Accessed 28th of February 2020, retrieved from: 

Assessed by:

Dr Imran Malik, General practitioner
Registration number: GMC: 4741365

Dr Imran Malik studied undergraduate medicine at King's College University in Central London and clinical studies at the prestigious King's College Hospital. He graduated with a MBBS degree in 2000 and went on to gain postgraduate memberships with the Royal Society of Medicine and also General Practice in 2006.