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Drug Profile

The information on this site is intended to supplement and enhance, not replace, the advice of a physician who is familiar with your medical history. Decisions about your health should always be made ONLY after detailed conversation with your doctor.

Generic drug name: erythromycin (er ITH roe my sin)
GENERIC: available FAMILY: Macrolides
Find the drug label by searching at DailyMed.

Pregnancy and Breast-feeding Warnings [top]

Pregnancy Warning

No data is available for erythromycin, as it was not tested properly in animal studies. Use during pregnancy only for clear medical reasons. Tell your doctor if you are pregnant or thinking of becoming pregnant before you take this drug.

Breast-feeding Warning

Erythromycin is excreted in human milk. Because of the potential for serious adverse effects in nursing infants, you should not take this drug while nursing.

Safety Warnings For This Drug [top]

Antibiotic-Associated Diarrhea

Antibiotic-associated diarrhea (AAD) is quite common and its incidence varies from 5% to 20% of patients depending on which antibiotic they are taking, although practically all antibiotics have been associated with AAD. Fortunately, most cases are mild and self-limited, ending with the cessation of use of the offending antibiotic. The antibiotics most commonly associated with this mild form of AAD include ampicillin, amoxicillin, cephalosporins and clindamycin.[1] There have been studies in children or adults in which the use of prophylactic yogurt in people using antibiotics has significantly reduced the occurrence or severity of AAD.[2],[3] However, 10% to 20% of all patients who get AAD (0.5% to 4% of patients using antibiotics) will get the more severe form of AAD known as pseudomembranous colitis (see below). If you are taking any antibiotic and develop diarrhea after starting to use the drug, call your physician to discuss whether another antibiotic should be used and to discuss the need for rehydration due to the fluid loss from the diarrhea.

Pseudomembranous colitis has been reported with nearly all antibacterial agents and may range in severity from mild to life-threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhea subsequent to the administration of antibacterial agents.

Because antibiotic therapy has been associated with severe colitis, which may end fatally, it should be reserved for serious infections where less toxic antimicrobial agents are inappropriate, as described in the INDICATIONS AND USAGE section. It should not be used in patients with nonbacterial infections such as most upper respiratory tract infections. Treatment with antibacterial agents alters the normal flora of the colon and may permit over-growth of clostridia. Studies indicate that a toxin produced by Clostridium difficile is one primary cause of "antibiotic-associated colitis."

After the diagnosis of pseudomembranous colitis has been established, therapeutic measures should be initiated. Mild cases of pseudomembranous colitis usually respond to drug discontinuation alone. In moderate to severe cases, consideration should be given to management with fluids and electrolytes, protein supplementation, and treatment with an antibacterial drug that is clinically effective against C. difficile colitis.

Diarrhea, colitis, and pseudomembranous colitis have been observed to begin up to several weeks following cessation of therapy.

Facts About This Drug [top]

Erythromycin (E.E.S., E.E.S. 200, E.E.S. 400, ERYC, ERYPED, ERY-TAB, ERYTHROCIN, PCE, PEDIAMYCIN, PEDIAMYCIN 400) is used in the treatment of infections caused by bacteria. It works by killing bacteria or preventing their growth. This drug is used to treat infections in many different parts of the body. Erythromycin will not work for colds, flu or other viral infections.

Adverse effects

This antibiotic may cause stomach or abdominal cramps and pain, watery diarrhea that may also be...

Erythromycin (E.E.S., E.E.S. 200, E.E.S. 400, ERYC, ERYPED, ERY-TAB, ERYTHROCIN, PCE, PEDIAMYCIN, PEDIAMYCIN 400) is used in the treatment of infections caused by bacteria. It works by killing bacteria or preventing their growth. This drug is used to treat infections in many different parts of the body. Erythromycin will not work for colds, flu or other viral infections.

Adverse effects

This antibiotic may cause stomach or abdominal cramps and pain, watery diarrhea that may also be bloody, nausea, vomiting, difficulty hearing, tinnitus (a ringing noise in the ears) or deafness.[4],[5]

Liver damage

People who use a particular type of erythromycin called erythromycin estolate (a "Do Not Use" drug) are about 20 times more likely to suffer liver damage (toxicity) from the drug than people who use other forms.[6] Therefore, you should not take erythromycin estolate.[7] If you have liver disease, you should take less than the usual adult dose of erythromycin.

Cardiovascular adverse events

For many years, erythromycin was not believed to cause serious adverse reactions. However, more recently, there have been reports in the medical literature of a change in electrical conduction in the heart (QT prolongation) that can increase the risk of a potentially fatal heart rhythm disturbance known as torsades de pointes. “Torsades de pointes” is a French phrase that means “twisted point,” describing the appearance of this rhythm disturbance on an electrocardiogram. These reports often have involved the injectable form of erythromycin.[8]

Research published in 2004, in the New England Journal of Medicine reported that patients using erythromycin had an increased risk of death from cardiac causes compared with patients not taking antibiotics.[9]

In 2012, Prescrire International published an article with information from a Canadian study on the use of macrolide antibiotics and calcium channel blocker drugs (a drug class used to treat hypertension) in elderly patients. The study found that patients using this drug combination experienced an increased risk of hypotension. According to the article, the risk of hypotension occurred with erythromycin and clarithromycin.[10]

In 2013, information from a Swedish study was published, showing that the use of erythromycin in pregnant women was associated with a risk of cardiovascular defects in infants born to these mothers. The article stated that this was a follow-up study to previous studies on this association and that the results from the previous studies led to a warning in Sweden on the use of erythromycin in early pregnancy.[11]

In 2013, the Annals of Internal Medicine published an article on the co-administration of statins (atorvastatin, lovastatin, simvastatin) with macrolide antibiotics, such as clarithromycin, erythromycin and azithromycin, in patients older than 65 years. The data reviewed showed that patients using atorvastatin, lovastatin or simvastatin experienced statin drug toxicity with co-administration of clarithromycin or erythromycin.[12]

Regulatory actions surrounding erythromycin

2012: In February, the Food and Drug Administration issued information concerning the use of erythromycin and QT interval prolongation (changes in the electrical activity of the heart). The warning stated that post-marketing cases of torsades de pointes (abnormal heart rhythm) have been reported in patients taking erythromycin. The advisory noted that fatalities in these cases have also been reported.[13]

2018: The FDA approved revisions to the product labeling for erythromycin indicating that the antibiotic should never be used by patients taking lovastatin (ALTOPREV) or simvastatin (VYTORIN, ZOCOR) because of an increased risk of muscle weakness and breakdown (myopathy and rhabdomyolysis) with concomitant use.[14]

In 2020, the BMJ published a study suggesting that children born to mothers who used macrolide antibiotics during pregnancy have an increased risk of malformations.[15]

Before You Use This Drug [top]

Tell your doctor if you have or have had:

  • allergies to erythromycin
  • an unusual reaction to erythromycin
  • heart or liver problems
  • hearing loss
  • pregnancy or are breast-feeding

Tell your doctor about any other drugs you take, including aspirin, herbs, vitamins, and other nonprescription products.

When You Use This Drug [top]

  • Check with your doctor if there is no improvement within a few days.
  • If you plan to have any surgery, including dental, tell your doctor that you take this drug.

How to Use This Drug [top]

  • If you miss a dose, take it as soon as you remember, but skip it if it is almost time for the next dose. Do not take double doses.
  • Do not share your medication with others.
  • Take the drug at the same time(s) each day.
  • Take this drug for the prescribed length of time. If you stop too soon, your symptoms could come back.
  • Take with a full glass (eight ounces) of water on an empty stomach. If stomach irritation occurs, take with food.
  • Store at room temperature with lid on tightly. Do not store in the bathroom. Do not expose to heat, moisture, or strong light. Keep out of reach of children.

Interactions with Other Drugs [top]

The following drugs, biologics (e.g., vaccines, therapeutic antibodies), or foods are listed in Evaluations of Drug Interactions 2003 as causing “highly clinically significant” or “clinically significant” interactions when used together with any of the drugs in this section. In some sections with multiple drugs, the interaction may have been reported for one but not all drugs in this section, but we include the interaction because the drugs in this section are similar to one another. We have also included potentially serious interactions listed in the drug’s FDA-approved professional package insert or in published medical journal articles. There may be other drugs, especially those in the families of drugs listed below, that also will react with this drug to cause severe adverse effects. Make sure to tell your doctor and pharmacist the drugs you are taking and tell them if you are taking any of these interacting drugs:

ACCOLATE, ALFENTA, alfentanil, atorvastatin, AVELOX, carbamazepine, cilostazol, clozapine, CLOZARIL, COUMADIN, cyclosporine, DEPAKENE/DEPAKOTE, DETROL, digoxin, disopyramide, docetaxel, ELIXOPHYLLIN, ERGOMAR, ERGOSTAT, ergotamine, FARESTON, HALCION, LANOXICAPS, LANOXIN, LIPITOR, lovastatin, MEDROL, methylprednisolone, MEVACOR, midazolam, mizolastine, moxifloxacin, NEORAL, NORPACE, NORVIR, ORAP, pimozide, PLETAL, PROGRAF, ritonavir, SANDIMMUNE, sildenafil, SLO-BID, tacrolimus, TAXOTERE, TEGRETOL, THEO-24, theophylline, tolterodine, toremifene, triazolam, TUBARINE, tubocurarine, valproic acid, VERSED, VIAGRA, VIGAMOX, warfarin, zafirlukast.

Adverse Effects [top]

Call your doctor immediately if you experience:

  • severe, watery diarrhea (may contain blood)
  • severe stomach pain
  • abnormal tiredness or weakness
  • yellow eyes or skin
  • temporary hearing loss
  • fever
  • nausea or vomiting
  • skin rash, redness, or itching
  • pain, swelling, or redness at site of injection
  • irregular or slow heart rate
  • recurrent fainting

Call your doctor if these symptoms continue:

  • sore mouth or tongue
  • white patches in mouth or tongue
  • mild abdominal or stomach cramping and discomfort
  • vaginal itching and discharge
  • diarrhea
  • nausea or vomiting

Periodic Tests[top]

Ask your doctor which of these tests should be done periodically while you are taking this drug:

  • electrocardiogram (ECG or EKG)
  • liver function determinations

last reviewed October 31, 2023