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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Other
Erythromycin Ethylsuccinate is a macrolide antibiotic used to treat various bacterial infections, including respiratory tract infections, skin conditions, and certain sexually transmitted diseases by inhibiting bacterial protein synthesis.
Name
Erythromycin Ethylsuccinate
Raw Name
ERYTHROMYCIN ETHYLSUCCINATE
Category
Other
Drug Count
4
Variant Count
25
Last Verified
February 17, 2026
RxCUI
686400, 686405, 863603, 863606, 686418, 686402, 686420
UNII
1014KSJ86F
About Erythromycin Ethylsuccinate
Erythromycin Ethylsuccinate is a macrolide antibiotic used to treat various bacterial infections, including respiratory tract infections, skin conditions, and certain sexually transmitted diseases by inhibiting bacterial protein synthesis.
Detailed information about Erythromycin Ethylsuccinate
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Erythromycin Ethylsuccinate.
Erythromycin Ethylsuccinate is a well-established macrolide antibiotic (a class of drugs that inhibit bacterial growth) derived from the metabolic products of Saccharopolyspora erythraea (formerly Streptomyces erythreus). It is the ethylsuccinate ester of erythromycin, specifically formulated to improve the drug's stability in the acidic environment of the stomach and to enhance its palatability, making it a preferred choice for pediatric oral suspensions. Since its initial FDA approval in the mid-20th century, Erythromycin Ethylsuccinate has remained a cornerstone in the treatment of a wide array of infections caused by susceptible Gram-positive and some Gram-negative bacteria.
As a macrolide, Erythromycin Ethylsuccinate belongs to the same pharmacological family as newer agents like azithromycin and clarithromycin. However, it retains a unique clinical profile, particularly in its role as an alternative for patients with penicillin allergies. Healthcare providers typically prescribe this medication for infections of the upper and lower respiratory tracts, skin and soft tissue infections, and specific infections like diphtheria, pertussis (whooping cough), and erythrasma. It is also utilized in the management of certain sexually transmitted infections, such as syphilis and chlamydia, when other first-line agents are not suitable.
The antibacterial activity of Erythromycin Ethylsuccinate is primarily bacteriostatic (inhibiting growth), although it may be bactericidal (killing bacteria) at high concentrations or against highly susceptible organisms. At the molecular level, the drug exerts its effect by penetrating the bacterial cell membrane and reversibly binding to the 50S subunit of the bacterial ribosome. Specifically, it binds to the 23S ribosomal RNA molecule, which effectively blocks the translocation step of protein synthesis. By preventing the transfer of the growing peptide chain from the A-site to the P-site, the drug halts the production of essential bacterial proteins, thereby preventing the bacteria from replicating and spreading.
One of the defining characteristics of Erythromycin Ethylsuccinate is its selective toxicity. It targets the 70S ribosome found in bacteria but does not bind significantly to the 80S ribosome found in human cells. This selectivity is what allows the drug to eliminate pathogens while minimizing direct toxicity to the host's cellular machinery. However, resistance can occur if bacteria modify their ribosomal binding sites (often through methylation) or utilize efflux pumps to remove the drug from the cell.
Understanding the pharmacokinetics of Erythromycin Ethylsuccinate is essential for optimizing therapeutic outcomes.
Erythromycin Ethylsuccinate is FDA-approved for a variety of clinical indications. Your healthcare provider may prescribe it for:
Erythromycin Ethylsuccinate is available in several oral formulations to accommodate different patient needs:
> Important: Only your healthcare provider can determine if Erythromycin Ethylsuccinate is right for your specific condition. The choice of antibiotic depends on the suspected pathogen, local resistance patterns, and your individual health history.
The standard adult dosage of Erythromycin Ethylsuccinate varies based on the severity and type of infection. For most common infections, the typical dose is 400 mg every 6 hours or 800 mg every 12 hours.
Pediatric dosing is strictly based on body weight and the severity of the infection. The usual range is 30 to 50 mg/kg/day in equally divided doses (usually every 6 to 12 hours).
For patients with mild to moderate kidney dysfunction, dosage adjustments are usually not necessary because the drug is primarily cleared by the liver. However, in cases of severe renal impairment (creatinine clearance less than 10 mL/min), healthcare providers may monitor patients closely for toxicity and consider a dose reduction, as the half-life may be slightly extended.
Since Erythromycin Ethylsuccinate is heavily metabolized and excreted by the liver, it should be used with extreme caution in patients with impaired hepatic function. In some cases, a dose reduction or an alternative antibiotic may be required to prevent drug accumulation and hepatotoxicity.
Older adults often have a higher risk of developing certain side effects, such as hearing loss (ototoxicity) or heart rhythm issues (QT prolongation). While standard doses are often used, healthcare providers typically exercise caution and monitor for these specific adverse events.
To ensure the medication works effectively and to minimize side effects, follow these guidelines:
If you miss a dose, take it as soon as you remember. If it is almost time for your next scheduled dose, skip the missed dose and resume your regular schedule. Never double the dose to 'catch up,' as this increases the risk of gastrointestinal toxicity.
Symptoms of an overdose may include severe nausea, vomiting, diarrhea, and hearing loss. In the event of a suspected overdose, contact your local poison control center or seek emergency medical attention immediately. Treatment is generally supportive, focusing on maintaining hydration and managing symptoms.
> Important: Follow your healthcare provider's dosing instructions precisely. Do not adjust your dose or stop the medication without medical guidance.
The most frequent adverse reactions associated with Erythromycin Ethylsuccinate involve the gastrointestinal (GI) tract. These effects occur because erythromycin acts as an agonist at motilin receptors in the gut, which stimulates intestinal movement.
These symptoms are usually dose-related and may subside if the medication is taken with food or if the dose is reduced by a healthcare provider.
> Warning: Stop taking Erythromycin Ethylsuccinate and call your doctor immediately if you experience any of these.
Erythromycin Ethylsuccinate is generally intended for short-term use (7 to 14 days). Prolonged or repeated use may result in:
No FDA black box warnings currently exist for Erythromycin Ethylsuccinate. However, the FDA does provide strong warnings regarding its potential for serious drug interactions and its effects on the heart's QT interval.
Report any unusual symptoms to your healthcare provider to ensure your treatment remains safe and effective.
Erythromycin Ethylsuccinate is a potent antibiotic that must be used with care. It is essential to inform your healthcare provider of your full medical history, especially any history of liver disease, kidney disease, or heart rhythm disorders. Because this drug is a significant inhibitor of the CYP3A4 enzyme, it can cause other medications to reach toxic levels in your body. Always provide a complete list of all medications, including over-the-counter drugs and herbal supplements, to your pharmacist and doctor.
No FDA black box warnings for Erythromycin Ethylsuccinate. While it lacks a boxed warning, the clinical precautions regarding its use with certain other medications (like statins or certain heart rhythm drugs) are considered high-priority safety concerns.
For most short-term courses, intensive lab monitoring is not required. However, in specific scenarios, your doctor may order:
Erythromycin Ethylsuccinate generally does not interfere with the ability to drive or operate machinery. However, if you experience dizziness or fatigue as a side effect, you should avoid these activities until you know how the medication affects you.
While alcohol does not have a direct, dangerous interaction with erythromycin like it does with metronidazole, it is generally advised to avoid alcohol while fighting an infection. Alcohol can dehydrate the body and may worsen the gastrointestinal side effects (nausea, stomach pain) associated with the medication.
There is no withdrawal syndrome associated with stopping Erythromycin Ethylsuccinate. However, stopping the drug before the full course is completed can lead to a relapse of the infection and promotes the development of antibiotic resistance. Always finish the entire bottle as prescribed.
> Important: Discuss all your medical conditions with your healthcare provider before starting Erythromycin Ethylsuccinate. Transparency is key to preventing serious adverse events.
Certain drugs must NEVER be taken with Erythromycin Ethylsuccinate because the interaction can be life-threatening:
Erythromycin may interfere with the fluorometric determination of urinary catecholamines, potentially leading to false-positive results for certain adrenal tumors. It can also interfere with certain liver function tests (AST/ALT) if using specific colorimetric assay methods.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking. A 'brown bag' review of your medications is the safest way to prevent interactions.
Erythromycin Ethylsuccinate must NEVER be used in the following circumstances:
In these cases, a healthcare provider will perform a careful risk-benefit analysis:
Patients allergic to one macrolide are highly likely to be allergic to others. If you have had a reaction to Zithromax (azithromycin) or Biaxin (clarithromycin), you must inform your doctor, as Erythromycin Ethylsuccinate will likely cause a similar or more severe reaction.
> Important: Your healthcare provider will evaluate your complete medical history before prescribing Erythromycin Ethylsuccinate. Never share your antibiotic with others, as their contraindications may differ from yours.
Erythromycin Ethylsuccinate is generally classified as FDA Pregnancy Category B. This means that animal reproduction studies have failed to demonstrate a risk to the fetus, and there are no adequate and well-controlled studies in pregnant women. Erythromycin is often considered a safe alternative for treating certain infections (like chlamydia or syphilis) in pregnant women who are allergic to penicillin. However, it should only be used during pregnancy if clearly needed and prescribed by a doctor. Some studies have suggested a potential link between erythromycin exposure in early pregnancy and cardiovascular malformations, though the evidence is not definitive.
Erythromycin is excreted in human breast milk. While it is generally considered compatible with breastfeeding by many authorities, there is a potential risk of the infant developing Infantile Hypertrophic Pyloric Stenosis (IHPS) if exposed to erythromycin through breast milk or direct administration. Nursing mothers should monitor their infants for projectile vomiting or irritability and discuss the risks and benefits with a pediatrician.
Erythromycin Ethylsuccinate is widely used in children for respiratory and skin infections. It is particularly valued for treating pertussis. However, the risk of IHPS is highest in infants under 6 weeks of age. Pediatricians weigh the necessity of the antibiotic against this risk, especially when treating infants for whooping cough.
Clinical studies have shown that elderly patients may be more susceptible to developing erythromycin-induced hearing loss (ototoxicity), particularly if they have underlying kidney or liver issues. Additionally, older adults are at a higher risk for QT prolongation and the resulting arrhythmias. Healthcare providers often start at the lower end of the dosing range and monitor heart and liver function closely.
While the kidneys are not the primary route of excretion, patients with severe renal failure (GFR < 10 mL/min) may experience a buildup of the drug. Dose adjustments are not standardized but clinical monitoring for side effects (like GI distress or hearing changes) is essential. Erythromycin is not significantly removed by hemodialysis or peritoneal dialysis.
This is the most critical population for dose monitoring. In patients with significant liver disease, the half-life of erythromycin can be greatly extended. If use is necessary, liver enzyme monitoring is recommended, and the dose may need to be reduced to prevent drug-induced liver injury.
> Important: Special populations require individualized medical assessment. Always consult with a specialist if you fall into one of these categories.
Erythromycin Ethylsuccinate is a macrolide antibiotic that inhibits protein synthesis in susceptible organisms. It accomplishes this by binding reversibly to the 50S ribosomal subunit of the bacterial ribosome. This binding occurs at the donor site (P-site), which prevents the translocation of the peptide chain from the A-site to the P-site. By inhibiting the enzyme peptidyl transferase and blocking the assembly of proteins, the drug effectively stops bacterial growth and replication. Because human ribosomes (80S) differ structurally from bacterial ribosomes (70S), the drug exhibits selective toxicity toward bacteria.
The efficacy of erythromycin is primarily related to the time the concentration of the drug remains above the Minimum Inhibitory Concentration (MIC) for the target pathogen (Time > MIC). It is generally bacteriostatic but can be bactericidal against highly sensitive organisms like Streptococcus pyogenes or Streptococcus pneumoniae at high concentrations. The onset of action is typically within 1 to 4 hours of administration, though clinical improvement of symptoms may take 24 to 48 hours.
| Parameter | Value |
|---|---|
| Bioavailability | 30% to 65% (Variable by salt) |
| Protein Binding | 70% to 90% |
| Half-life | 1.5 to 2.5 hours |
| Tmax | 1 to 4 hours |
| Metabolism | Hepatic (CYP3A4) |
| Excretion | Biliary/Fecal (>90%), Renal (2-5%) |
Erythromycin Ethylsuccinate is classified as a Macrolide Antibiotic. It is the 'parent' drug of the class, which also includes semi-synthetic derivatives like Azithromycin (a nitrogen-containing azalide) and Clarithromycin. These drugs are characterized by a large macrocyclic lactone ring to which one or more deoxy sugars are attached.
Medications containing this ingredient
Common questions about Erythromycin Ethylsuccinate
Erythromycin Ethylsuccinate is a macrolide antibiotic used to treat a wide variety of bacterial infections. It is commonly prescribed for respiratory tract infections like pneumonia and bronchitis, as well as skin infections and 'Strep throat' in patients who cannot take penicillin. It is also a primary treatment for pertussis (whooping cough) and can be used for certain sexually transmitted infections like syphilis and chlamydia. Additionally, it is used to treat erythrasma, a specific type of skin infection. Your doctor will determine if your specific infection is caused by bacteria that are susceptible to this medication.
The most common side effects are gastrointestinal in nature, including nausea, vomiting, stomach cramps, diarrhea, and loss of appetite. These occur because erythromycin stimulates the motilin receptors in the gut, which increases intestinal contractions. Taking the medication with food can often help reduce these symptoms. While usually mild to moderate, these effects are the most frequent reason patients stop taking the medication. If you experience severe or persistent diarrhea, you should contact your healthcare provider immediately to rule out a more serious intestinal infection.
There is no known direct, dangerous interaction between alcohol and Erythromycin Ethylsuccinate that would cause a 'disulfiram-like' reaction. However, healthcare providers generally recommend avoiding alcohol while you are being treated for an infection. Alcohol can interfere with your body's ability to heal, cause dehydration, and may worsen the stomach upset and dizziness that are common side effects of the antibiotic. It is best to allow your body to focus on recovery without the added stress of processing alcohol. Always check with your doctor for personalized advice based on your health status.
Erythromycin Ethylsuccinate is generally considered one of the safer antibiotics to use during pregnancy and is classified as Category B. It has been used for decades to treat infections in pregnant women, particularly those with penicillin allergies. However, like all medications, it should only be used when clearly necessary. Some studies have looked into potential risks, but no definitive link to birth defects has been firmly established for the ethylsuccinate form. You should always have a detailed discussion with your obstetrician about the benefits of treating your infection versus any potential risks to the developing fetus.
Erythromycin begins working against bacteria within a few hours of the first dose as it enters the bloodstream and reaches the site of infection. However, you may not feel a significant improvement in your symptoms for 24 to 48 hours. It is vital to continue taking the medication for the full duration prescribed by your doctor, even if you start to feel better after just a day or two. Finishing the entire course ensures that all the bacteria are eliminated and prevents the infection from returning or becoming resistant to the antibiotic.
You can stop taking the medication without experiencing withdrawal symptoms, but you should never stop an antibiotic early unless directed by a healthcare provider. Stopping the medication before the full course is finished allows the strongest bacteria to survive and multiply. This can lead to a relapse of your infection that is much harder to treat because the remaining bacteria may have developed resistance to erythromycin. If you are experiencing severe side effects that make it difficult to continue, contact your doctor to discuss an alternative treatment rather than simply stopping the drug.
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and simply take the next one at the regular time. Do not take two doses at once to make up for the missed one, as this significantly increases your risk of experiencing severe nausea, vomiting, and stomach pain. To help you remember your doses, try using a pill organizer or setting an alarm on your phone. Consistency is key to keeping enough antibiotic in your system to kill the bacteria effectively.
Weight gain is not a typical or documented side effect of short-term treatment with Erythromycin Ethylsuccinate. In fact, due to the common gastrointestinal side effects like nausea and loss of appetite, some patients might experience slight temporary weight loss during a 7-to-10-day course. If you notice significant or rapid weight gain while taking this medication, it is more likely related to another underlying condition or a different medication you may be taking. You should discuss any unexpected changes in your weight with your healthcare provider for a proper evaluation.
Erythromycin Ethylsuccinate has a very high potential for drug interactions because it inhibits the CYP3A4 enzyme in the liver. This can cause other drugs, such as certain statins (cholesterol meds), blood thinners (warfarin), and heart medications, to build up to dangerous levels in your body. Some combinations, like taking erythromycin with pimozide or certain ergot medicines, are strictly forbidden because they can cause fatal heart rhythm problems. You must provide your doctor and pharmacist with a complete list of every medication and supplement you take to ensure they can screen for these dangerous interactions.
Yes, Erythromycin Ethylsuccinate is available as a generic medication in both tablet and oral suspension forms. Generic versions are required by the FDA to have the same active ingredient, strength, dosage form, and route of administration as the brand-name products (such as E.E.S. or EryPed). Generic versions are typically more cost-effective for patients while providing the same therapeutic benefits. Your pharmacist can help determine if a generic version is available for your specific prescription and whether it is covered by your insurance plan.