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Overview: Erythromycin is an antibiotic that is used to treat or prevent infections caused by certain bacteria. Common side effects include nausea, stomach pain, diarrhea, and loss of appetite. Tell your health care provider right away if you get severe diarrhea, even several months after stopping the medicine. Also, tell your health care provider right away if you get severe stomach pain, vomiting, rash, or a fast or skipping heartbeat.

Uses

What is erythromycin used for?

Erythromycin is an antibiotic that is commonly used for the following infections caused by certain bacteria.

Erythromycin is also commonly used to prevent certain bacterial infections, such as rheumatic fever and an infection in the lining of your heart known as endocarditis.

Erythromycin may also be used for other conditions as determined by your health care provider.

Erythromycin may not be appropriate for some of the infections listed above, depending on which germs are causing the infection. Bacteria in some locations may have developed resistance to erythromycin, which will make it not work as well.

How does erythromycin work (mechanism of action)?

Erythromycin stops certain types of bacteria from making proteins they need to grow and multiply.

How is erythromycin supplied (dosage forms)?

Brands and other names

  • E.E.S.
  • E-Mycin
  • Eryc
  • EryPed
  • Erythrocin
  • Ery-Tab
  • Pediamycin

Dosage forms and strengths

  • 250 mg delayed-release oral capsules
  • 250 mg, 333 mg, 500 mg delayed-release oral tablets
  • 250 mg, 400 mg, 500 mg oral tablets
  • 200 mg/5 mL, 400 mg/5 mL granules for oral suspension

Erythromycin is also available in injectable forms.

See also: Erythromycin ophthalmic and Erythromycin topical

How should I store erythromycin?

Oral Tablets and Capsules. Erythromycin tablets (including delayed-release tablets) and capsules should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). They can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place.

Oral Suspension. Erythromycin oral liquids should be stored below 77 F (20 C and 25 C), and some need to be stored in the refrigerator. They are good for a specific number of days, and this can vary among products. Throw away unused products according to how they are labeled. Ask your pharmacist if you have any questions about storing erythromycin oral liquids or when to throw them away.

Injection Liquid. Erythromycin injection is usually given by a health care provider in a hospital or clinic. If you will store erythromycin injection at home, follow the instructions given by your health care provider.

Side Effects

What are the most common side effects of erythromycin?

The most common side effects of erythromycin are listed below. Tell your health care provider if you have any of these side effects that bother you.

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

There may be other side effects of erythromycin that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of erythromycin?

While less common, the most serious side effects of erythromycin are described below, along with what to do if they happen.

Severe Allergic Reactions. Erythromycin may cause allergic reactions, which can be serious. Stop taking erythromycin and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking erythromycin. Call your health care provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Heart Rhythm Changes. Erythromycin may cause a rare, dangerous heart rhythm problem called QT prolongation and torsade de pointes. Some people have a higher risk of this, including people who are older, have other people in their family who have had these conditions, have low potassium or magnesium levels, or who take medicines that can prolong the QT interval. Tell your health care provider right away if you faint or have changes in your heart rate or rhythm, such as a fast or skipping heartbeat.

Antibiotic-Associated Diarrhea. An overgrowth of germs called Clostridioides difficile, or “C. diff,” can happen in your gut with many types of antibiotics, including erythromycin. This can cause a condition known as antibiotic-associated diarrhea and can happen two or more months after stopping the antibiotic. Call your health care provider right away if you have any of the following symptoms of this condition.

  • Watery diarrhea
  • Diarrhea that does not go away
  • Blood in your stool (poop)
  • Severe stomach cramps
  • Fever that starts after you start or finish the medicine

Pyloric Stenosis. A condition called infantile hypertrophic pyloric stenosis can happen in babies after being given erythromycin. This condition makes it harder for food to move from the baby’s stomach into their intestines. It leads to vomiting, which can be severe. Call your health care provider right away if your baby throws up or is irritable after feeding.

Warnings & Precautions

Who should not use erythromycin?

Allergies to Ingredients. People who are allergic to any of the following should not take erythromycin.

  • Erythromycin
  • E.E.S.
  • E-Mycin
  • Eryc
  • EryPed
  • Erythrocin
  • Ery-Tab
  • Pediamycin
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific erythromycin products they stock.

Drug Interactions. Erythromycin should not be taken while you are using certain other medicines. Before taking erythromycin, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

What should I know about erythromycin before using it?

Do not take erythromycin unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share erythromycin with other people, even if they have the same condition as you. It may harm them.

Keep erythromycin out of the reach of children. As some forms of this medicine should be kept in a refrigerator, take special precautions to keep it away from children who also use the refrigerator.

Use an accurate measuring device to measure your liquid erythromycin dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist what measuring device to use.

People who are 65 or older can be at greater risk for some side effects from erythromycin. Talk to your health care provider about your risks if you are in this age group.

What should I tell my health care provider before using erythromycin?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if erythromycin is right for you.

In particular, make sure that you discuss any of the following.

Myasthenia Gravis. Tell your health care provider if you have a condition called myasthenia gravis. Erythromycin may make your symptoms worse. 

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

Pregnancy. It is not known if or how erythromycin could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. Erythromycin passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take erythromycin while breastfeeding.

Interactions

Does erythromycin interact with foods or drinks?

Erythromycin can be taken without regard to meals, but it is absorbed best if taken on an empty stomach, at least one half to two hours before meals.

It is unknown if drinking alcohol will affect erythromycin, but heavy drinking can slow your immune response and make it harder for your body to fight infection. 

Does erythromycin interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking erythromycin.

  • Any medicine that can cause QT prolongation, which is a potentially dangerous heart rhythm problem, such as quinidine, procainamide, dofetilide, amiodarone, or sotalol
  • Pimozide, which is a medicine used to treat Tourette syndrome
  • An ergot, such as ergotamine (Ergomar) or dihydroergotamine (Migranal or Trudhesa), which is a medicine used to treat migraine
  • A statin, such as atorvastatin (Lipitor and others), lovastatin (Altoprev), or simvastatin (Zocor), which is a medicine to lower cholesterol
  • Alprazolam (Xanax) or triazolam (Halcion), which are medicines used for anxiety, muscle spasms, or seizures
  • Amlodipine (Norvasc and others), diltiazem (Cardizem CD and others), or verapamil (Verelan, Verelan PM), which are medicines used for high blood pressure or other conditions
  • Carbamazepine (Carbatrol, Tegretol, and others) or phenytoin (Dilantin, Phenytek, and others), which are medicines commonly used to control seizures
  • Cilostazol, which are medicines used to prevent blood clots
  • Colchicine, which is commonly used for gout
  • Cyclosporine (Gengraf, Neoral, Sandimmune, and others) or tacrolimus (Prograf, Astagraf XL, and others), which are medicines that suppresses your immune system
  • Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure
  • Methylprednisolone, which is a medicine for certain inflammatory conditions
  • Rifabutin (Mycobutin), which is a medicine used to prevent Mycobacterium avium complex infection
  • Sildenafil (Viagra, Revatio), which is a medicine used for erectile dysfunction or pulmonary arterial hypertension (PAH)
  • Theophylline (Theo-24, Elixophyllin), which is a medicine for asthma or certain other breathing problems
  • Valproic acid, divalproex sodium, and valproate sodium (Depakote and others), which are medicines used for seizures and other conditions

Erythromycin may alter the blood levels of many other medicines. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with erythromycin. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much erythromycin?

If you or someone else has used too much erythromycin, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of erythromycin?

Oral Products. If you miss an oral dose of erythromycin, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses. 

Injectable Products. Erythromycin injection is usually given by a health care provider in a hospital. Your health care provider will make sure you are receiving erythromycin injection as scheduled. If you miss an appointment to get your erythromycin injection dose, call to make another appointment as soon as possible. 

It is important to complete your prescribed course of erythromycin, even if your symptoms get better or go away. This will reduce the risk that future infections are resistant to erythromycin or other similar medicines.