Comparative Pharmacology
Head-to-head clinical analysis: E MYCIN E versus E E S 200.
Peer-Reviewed Evidence
Head-to-head clinical analysis: E MYCIN E versus E E S 200.
E-MYCIN E vs E.E.S. 200
Head-to-head clinical comparison of therapeutic indices and safety profiles.
Erythromycin binds to the 50S ribosomal subunit of susceptible bacteria, inhibiting protein synthesis by blocking the translocation of peptide chains.
Erythromycin acts by binding to the 50S ribosomal subunit of susceptible bacteria, inhibiting protein synthesis by blocking translocation of peptidyl-tRNA. It may also inhibit ribosomal assembly.
Treatment of infections caused by susceptible strains of microorganisms (e.g., respiratory tract infections, skin infections, pertussis, diphtheria, intestinal amebiasis)Prophylaxis of rheumatic feverOphthalmic neonatal conjunctivitis due to Chlamydia trachomatis
Treatment of infections caused by susceptible strains of microorganisms: respiratory tract infections, pertussis, diphtheria, chlamydial infections, syphilis, Legionnaires' diseaseProphylaxis of recurrent rheumatic feverOff-label: gastroparesis, as a prokinetic agent
250-500 mg orally every 6 hours or 333-500 mg every 8 hours; maximum 4 g/day.
400 mg orally every 6 hours as the ethylsuccinate salt. Maximum daily dose 4 g.
None Documented
None Documented
Terminal elimination half-life is 1.5-3 hours in adults; prolonged to 4-6 hours in neonates and patients with hepatic impairment.
Approximately 1.5-2 hours in adults with normal renal function; may be prolonged to 5-6 hours in severe renal impairment.
Erythromycin is primarily metabolized by the hepatic cytochrome P450 enzyme system (CYP3A4) via demethylation.
Metabolized primarily via hepatic CYP3A4 and is a moderate inhibitor of CYP3A4. Eliminated mainly in bile, with some renal excretion.
Primarily excreted unchanged in urine (70-80%) via glomerular filtration and tubular secretion; 15-20% excreted in feces via biliary elimination.
Primarily hepatic metabolism and biliary excretion; approximately 5-15% of active drug excreted renally, with fecal elimination accounting for the majority of the remaining dose.
70-80% bound, primarily to albumin.
70-80% bound primarily to alpha-1-acid glycoprotein (AAG) and to a lesser extent albumin.
0.6-0.9 L/kg; indicates extensive tissue penetration, including lung, tonsils, and middle ear fluid.
0.5-0.9 L/kg; extensive tissue penetration (except CSF and brain unless meninges inflamed).
Oral: 30-40% (erythromycin base is acid-labile); enteric-coated formulations: 40-60%.
Oral: 25-50% (base); variable due to acid instability; enteric-coated formulations improve absorption.
No dose adjustment required for mild to moderate renal impairment. For severe renal impairment (eGFR < 10 mL/min), reduce dose by 50% or extend interval to every 12-18 hours.
No dose adjustment required for GFR >10 mL/min. For GFR <10 mL/min, reduce dose by 25-50% or administer at prolonged intervals.
Child-Pugh Class A: no adjustment. Class B: reduce dose by 50% or extend interval. Class C: avoid use or reduce dose by 75% and monitor closely.
Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose by 50%. Child-Pugh C: Reduce dose by 75% or avoid use.
30-50 mg/kg/day orally divided every 6-8 hours; maximum 2 g/day. For severe infections, up to 75 mg/kg/day divided every 6 hours.
30-50 mg/kg/day orally in divided doses every 6 hours, as ethylsuccinate. Maximum 2 g/day.
Consider reduced renal function; monitor for QT prolongation and ototoxicity. Initiate at lower end of dosing range (250 mg every 6 hours) and titrate based on response and tolerance.
No specific dose adjustment, but monitor for ototoxicity and QT prolongation. Initiate at lower end of dosing range.
Erythromycin has been associated with prolongation of the QT interval and rare cases of ventricular arrhythmias, including torsades de pointes, which can be fatal. Avoid use in patients with known QT prolongation, electrolyte abnormalities, or concurrent use of other QT-prolonging drugs.
Increased risk of infantile hypertrophic pyloric stenosis (IHPS) when used in neonates; use only when no alternative therapy is available.
["QT interval prolongation and risk of cardiac arrhythmias","Hepatic dysfunction and hepatitis","Exacerbation of myasthenia gravis","Clostridium difficile-associated diarrhea","Allergic reactions including anaphylaxis","Superinfection with prolonged use"]
Potential for QT prolongation and torsades de pointes, especially in patients with electrolyte disturbances or concurrent use of other QT-prolonging drugs; hepatic impairment; myasthenia gravis worsening; superinfection; risk of IHPS in neonates; caution in renal impairment.
["Hypersensitivity to erythromycin or any macrolide antibiotic","Concurrent use with terfenadine, astemizole, or cisapride due to risk of cardiotoxicity","Preexisting QT prolongation or history of ventricular arrhythmias"]
Hypersensitivity to erythromycin or any macrolide antibiotic; concomitant use with CYP3A4 substrates that prolong QT interval (e.g., cisapride, pimozide, ergotamine) due to risk of arrhythmias.
Data Pending Review
Data Pending Review
Take on an empty stomach: 1 hour before or 2 hours after meals. Avoid grapefruit juice as it can increase erythromycin serum concentrations and risk of QT prolongation. Avoid alcohol as it may increase hepatotoxicity risk. High-fat meals may delay absorption.
Administration with food may reduce gastrointestinal adverse effects. Grapefruit and grapefruit juice should be avoided as they inhibit CYP3A4 and can increase erythromycin levels, raising risk of QT prolongation and other adverse effects. Avoid alcohol as it may exacerbate GI irritation.
E-MYCIN E (erythromycin) is classified as FDA Pregnancy Category B. No teratogenic effects have been demonstrated in animal studies, and adequate well-controlled studies in pregnant women have not shown fetal risk. However, data are limited; use during pregnancy only if clearly needed. First trimester: No evidence of increased risk of major malformations. Second and third trimesters: Considered safe; erythromycin is a first-line agent for Group B Streptococcus prophylaxis during labor.
Erythromycin (E.E.S. 200) is classified as FDA Pregnancy Category B. Animal reproduction studies have not demonstrated fetal risk, but no adequate human studies exist. First trimester: No teratogenic effects reported; however, use only if clearly needed. Second and third trimesters: Considered safe; no known fetal toxicity. There is a potential association with pyloric stenosis in neonates if used after 32 weeks gestation, though absolute risk is low. Overall risk-benefit assessment should consider maternal infection treatment necessity.
Erythromycin is excreted into breast milk in small amounts (M/P ratio approximately 0.5-1.0). Breastfeeding is considered safe as concentrations are low and unlikely to cause adverse effects in the infant. However, caution is advised due to potential for gastrointestinal disturbances or sensitization. The AAP classifies erythromycin as compatible with breastfeeding.
Erythromycin is excreted into breast milk in small amounts. The milk-to-plasma ratio (M/P) is approximately 0.5. Oral absorption by the infant is minimal, and adverse effects are rare. However, there is a theoretical risk of infant gastrointestinal disturbance or allergic reaction. The American Academy of Pediatrics considers erythromycin compatible with breastfeeding. Caution is advised, especially in infants with jaundice or hepatic impairment.
No specific dosage adjustments are recommended during pregnancy. Pharmacokinetic changes (increased volume of distribution, altered clearance) are not clinically significant for erythromycin. Standard dosing (e.g., 250-500 mg PO QID) is used. For IV therapy, no adjustment needed.
Pregnancy induces physiological changes including increased plasma volume, renal blood flow, and hepatic metabolism. Erythromycin pharmacokinetics in pregnancy: decreased peak serum concentrations (Cmax) by 20-30%, increased volume of distribution, but no significant change in half-life. The area under the curve (AUC) may be reduced. Standard dosing (250-500 mg every 6 hours) is usually sufficient; however, severe infections may require higher doses or additional monitoring of therapeutic levels. No routine dose adjustment is recommended, but clinical response should be evaluated.
Category C
Category C
E-MYCIN E (erythromycin ethylsuccinate) is a macrolide antibiotic with bacteriostatic activity against gram-positive cocci and atypical pathogens. It is a prodrug that is hydrolyzed to active erythromycin. Administer on an empty stomach for optimal absorption. It may prolong QT interval; use with caution in patients with electrolyte disturbances or concurrent QT-prolonging drugs. Monitor for hepatotoxicity, especially in patients with pre-existing liver disease. It is a strong inhibitor of CYP3A4, increasing levels of statins, warfarin, and other drugs.
Erythromycin ethylsuccinate is a macrolide antibiotic with similar spectrum to penicillin. It is a CYP3A4 inhibitor; monitor for interactions with statins, warfarin, and other CYP3A4 substrates. QT prolongation risk; avoid with other QT-prolonging drugs. Use with caution in hepatic impairment. Common GI adverse effects may be mitigated by administration with food. It is pregnancy category B.
Take this medication exactly as prescribed, usually every 6 to 8 hours, on an empty stomach (1 hour before or 2 hours after meals).Do not crush or chew the tablets; swallow them whole with a full glass of water.Complete the full course of therapy even if you feel better to prevent antibiotic resistance.Avoid grapefruit juice as it may increase the effects and side effects of this medication.Contact your doctor immediately if you experience jaundice, dark urine, severe abdominal pain, or signs of liver problems.Inform your doctor about all medications you are taking, especially statins, warfarin, or other drugs metabolized by CYP3A4.Use effective contraception if you are of childbearing age; this medication may reduce the effectiveness of hormonal contraceptives.If you miss a dose, take it as soon as you remember. If it is almost time for the next dose, skip the missed dose and continue your regular schedule. Do not double the dose.
Take this medication exactly as prescribed, even if you feel better.Complete the full course of therapy to prevent resistance.May cause nausea, vomiting, abdominal pain, or diarrhea. Taking with food may reduce GI upset.Inform your doctor if you have liver disease, heart rhythm problems, or are taking other medications.Avoid grapefruit and grapefruit juice while on this medication due to potential interaction.Report any signs of allergic reaction (rash, hives, difficulty breathing) or severe diarrhea (watery or bloody stools).