What to Know About Oral Erythromycin

An antibiotic for inflammatory acne and much more

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Oral erythromycin is a prescription antibiotic that's classified as a macrolide antibiotic. It's used to stop the growth of bacteria. Erythromycin is used to treat both acute (short-term) and chronic (long-term) bacterial infections.

In tablet, capsule, granule, and suspension forms, oral erythromycin is available in several formulations, including erythromycin stearate and erythromycin ethylsuccinate.

It is sold in generic form and under the brand names:

  • ERY-C
  • Ery-Tab
  • EryPed
  • E-Mycin
  • Erythrocin
  • PCE

In addition to oral forms, this drug is sold as a topical gel and liquid, an eye ointment, and an intravenous solution.

A woman holds a white pill in one hand and a glass of water in the other.

Siriporn Kaenseeya / EyeEm / Getty Images


In pill form, erythromycin is approved by the Food and Drug Administration (FDA) for treating:

It's used off-label (without FDA approval) for treating:

High Rates of Resistance

Due to high rates of bacterial resistance that have developed, erythromycin is rarely used as an acne treatment.

Before Taking

Erythromycin isn't a right for everyone, and it isn't safe to use if you have certain conditions.

Before taking it, tell your healthcare provider if you:

  • Have ever had an allergic reaction to erythromycin or similar medications
  • Have been diagnosed with an irregular heartbeat or a heart problem called a prolonged QT interval
  • Have low levels of magnesium or potassium in your blood
  • Have been diagnosed with liver disease
  • Are pregnant, plan to become pregnant, or are breastfeeding
  • Are planning to have surgery, including dental surgery

These factors may influence your healthcare provider's decision about which antibiotic is right for you.

Precautions and Contraindications

Erythromycin use has contributed to the growing problem of bacterial resistance, which is caused by the overuse of antibiotics. To combat this serious problem, erythromycin should only be prescribed for infections that are known to respond well to this drug.

You shouldn't take erythromycin if you've ever had an allergic reaction to it or any of its ingredients.

Your healthcare provider will likely not give you erythromycin if you're currently taking any of these medications:

Pregnancy Warning

If you're pregnant, you shouldn't take a form of erythromycin called erythromycin estolate, which can cause pregnancy-related liver toxicity.

Other Macrolide Antibiotics

Other oral antibiotics in the same class as erythromycin include:


Erythromycin comes in the following strengths:

  • Oral granules: 200 milligrams (mg) per 5 milliliters (mL), or 400 mg per 5 mL when reconstituted
  • Oral tablets: 250 mg, 333 mg, 400 mg, 500 mg
  • Oral capsules: 250 mg

Adult dosages for the treatment of infections vary depending on the infectious agent and the product that's used.

The typical dose range is between 250 mg and 500 mg three or four times per day. For erythromycin stearate, the dose is 250mg to 500mg every 6 to 12 hours, and for ethylsuccinate, it is 400mg to 800mg every 6 to 12 hours.

A typical dose for acne begins at 250 mg or 500 mg twice a day, followed by a maintenance dose of once a day.

All listed dosages are according to the drug manufacturer. Check your prescription and talk to your healthcare provider to make sure you are taking the right dose for you.


Pediatric dosages for erythromycin are calculated based on weight.

How to Take and Store

Administration and storage considerations vary depending on the product.

  • Oral erythromycin should be taken by mouth.
  • Base, erythromycin particles in tablets (PCE), or stearate dosage forms should be taken on an empty stomach.
  • Delayed-release products and ethylsuccinate can be taken with or without meals, and taking them with meals may make medications more tolerable.

Follow your healthcare provider's instructions carefully. Do not crush or chew tablets or capsules, as it may impact the way the drug is released into your system.

Keep this and all medications away from children. You should store erythromycin at room temperature in its original container with the lid tightly closed. It's recommended that you don't store it in the bathroom, where it could be exposed to excess heat and moisture.

Different liquid preparations have different stabilities after reconstitution. Some suspensions are good at room temperature for 10 days while others are good for 35

Side Effects

You should be aware of possible side effects that may occur with erythromycin and know when to contact your healthcare provider.


The most common side effects of erythromycin include:

  • Nausea
  • Stomach pain
  • Vomiting
  • Diarrhea
  • Loss of appetite

Taking this medication with food may help reduce thesel side effects. Tell your healthcare provider if these symptoms are persistent or severe.


Less common side effects may be more serious. Contact your healthcare provider right away or get emergency medical help for any of the following:

  • Rash or hives
  • Itching
  • Wheezing or difficulty breathing or swallowing
  • Yellowed skin or eyes
  • Dark urine
  • Pale stools
  • Unusual fatigue
  • Pain in the upper right part of the stomach
  • Seizures
  • Fast, pounding, or irregular heartbeat
  • Severe diarrhea, possibly bloody, that may occur without fever and stomach cramps

Warnings and Interactions

Erythromycin carries a risk of toxicity to the heart. It can lengthen a measure of the heartbeat called the QT interval and potentially lead to a deadly heart rhythm called torsades de pointes. Your healthcare provider should carefully monitor your heart while you're taking this medication.

If you're at high risk of these problems, you may need regular testing to monitor your levels of:

  • Potassium
  • Magnesium
  • Calcium

Drugs that can have major harmful interactions with erythromycin include:

  • Theophylline: brand names are Elixophyllin, Quibron-T, Theo-24, Theochron, Theolair, Uniphyl
  • Verapamil: Calan, Covera HS, Veralan
  • Digoxin: Cardoxin, Digitek, Lanoxicaps, Lanoxin
  • Triazolam: Halcion
  • Tacrolimus: Astagraft XL, Envarsus XR, Prograf, Protopic
  • Colchicine: Colcrys, Gloperba

Common drugs that may have moderate interactions with erythromycin include:

Talk to your healthcare provider about all medications, supplements, and vitamins that you currently take. While some drugs pose minor interaction risks, others may outright contraindicate use or prompt careful consideration.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Prescribers' Digital Reference. Erythromycin - Drug summary.

  2. Baldwin H. Oral antibiotic treatment options for acne vulgarisJ Clin Aesthet Dermatol. 2020;13(9):26-32.

  3. National Institutes of Health, U.S. National Library of Medicine: MedlinePlus. Erythromycin.

  4. U.S. Food and Drug Administration: FDA AccessData. Ery-Ped (erhythromycin ethylsuccinate, USP) Rx only.

  5. Chien AL, Qi J, Rainer B, Sachs DL, Helfrich YR. Treatment of acne in pregnancyJ Am Board Fam Med. 2016;29(2):254-262. doi:10.3122/jabfm.2016.02.150165

  6. Hancox JC, Hasnain M, Vieweg WV, Gysel M, Methot M, Baranchuk A. Erythromycin, QTc interval prolongation, and torsade de pointes: Case reports, major risk factors and illness severityTher Adv Infect Dis. 2014;2(2):47-59. doi:10.1177/2049936114527744

  7. U.S. Food and Drug Administration: FDA AccessData. Pce (erythromycin) tablet.

By Angela Palmer
Angela Palmer is a licensed esthetician specializing in acne treatment.