E.E.S. 200
Clinical safety rating: caution
Comprehensive clinical and safety monograph for E.E.S. 200 (E.E.S. 200).
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.
| Metabolism | Metabolized primarily via hepatic CYP3A4 and is a moderate inhibitor of CYP3A4. Eliminated mainly in bile, with some renal excretion. |
| Excretion | 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. |
| Half-life | Approximately 1.5-2 hours in adults with normal renal function; may be prolonged to 5-6 hours in severe renal impairment. |
| Protein binding | 70-80% bound primarily to alpha-1-acid glycoprotein (AAG) and to a lesser extent albumin. |
| Volume of Distribution | 0.5-0.9 L/kg; extensive tissue penetration (except CSF and brain unless meninges inflamed). |
| Bioavailability | Oral: 25-50% (base); variable due to acid instability; enteric-coated formulations improve absorption. |
| Onset of Action | Oral: 1-2 hours (time to peak serum concentration); peak antibacterial effect correlates with serum levels. |
| Duration of Action | 6-12 hours (bacteriostatic effect persists while drug levels remain above MIC); clinical dosing every 6-12 hours. |
| Molecular Weight | 733.93 |
400 mg orally every 6 hours as the ethylsuccinate salt. Maximum daily dose 4 g.
| Dosage form | SUSPENSION |
| Renal impairment | No dose adjustment required for GFR >10 mL/min. For GFR <10 mL/min, reduce dose by 25-50% or administer at prolonged intervals. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose by 50%. Child-Pugh C: Reduce dose by 75% or avoid use. |
| Pediatric use | 30-50 mg/kg/day orally in divided doses every 6 hours, as ethylsuccinate. Maximum 2 g/day. |
| Geriatric use | No specific dose adjustment, but monitor for ototoxicity and QT prolongation. Initiate at lower end of dosing range. |
| 1st trimester | Erythromycin (E.E.S. 200) is generally considered safe; however, avoid use of erythromycin estolate due to increased risk of hepatotoxicity. |
| 2nd trimester | Generally safe; no known teratogenic effects in second trimester. |
| 3rd trimester | Generally safe; use near term may be associated with infantile hypertrophic pyloric stenosis (IHPS), especially if used after 32 weeks. |
Clinical note
Comprehensive clinical and safety monograph for E.E.S. 200 (E.E.S. 200).
| Placental transfer | Erythromycin crosses the placenta; fetal levels are approximately 5-20% of maternal serum concentrations. |
| Breastfeeding | Erythromycin is excreted into breast milk in small amounts. Although generally considered compatible with breastfeeding, potential risks include infant gastrointestinal disturbances and theoretical risk of pyloric stenosis. Monitor infant for diarrhea, rash, and feeding intolerance. |
■ FDA Black Box Warning
Increased risk of infantile hypertrophic pyloric stenosis (IHPS) when used in neonates; use only when no alternative therapy is available.
| Serious Effects |
Hypersensitivity to erythromycin or any macrolide antibioticConcurrent use with cisapride, pimozide, ergotamine, or dihydroergotamine (risk of QT prolongation and serious cardiac arrhythmias)Pre-existing QT interval prolongation or history of torsades de pointesHepatic impairment (especially with erythromycin estolate)
| Precautions | 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. |
| Food/Dietary | 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. |
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| Lactation Rating | L2 (probably compatible) / Safe |
| Teratogenic Risk | 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. |
| Fetal Monitoring | Maternal monitoring should include liver function tests (erythromycin can cause hepatotoxicity), auditory function (especially with high doses or renal impairment), and ECG for QT prolongation risk. Fetal monitoring includes ultrasound for growth and development if used in first trimester. Neonatal monitoring should include observation for symptoms of pyloric stenosis (projectile vomiting) if maternal use in late pregnancy. |
| Fertility Effects | No clinically significant effects on fertility have been reported in animal or human studies. Erythromycin does not affect reproductive hormones or gamete function at therapeutic doses. However, untreated infections can impair fertility, so appropriate treatment is beneficial. |
| Clinical Pearls | 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. |
| Patient Advice | 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). |