Comprehensive medication guide to Erythromycin Ethylsuccinate including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0–$20 copay for generic erythromycin ethylsuccinate on most commercial plans, Medicare Part D, and Medicaid; typically Tier 1 or Tier 2 on most formularies; prior authorization generally not required for standard acute antibiotic courses.
Estimated Cash Pricing
$15–$50 for a typical acute course of generic tablets or suspension with a GoodRx or SingleCare coupon; retail prices without a coupon can reach $80–$200+ for suspension formulations depending on the pharmacy.
Medfinder Findability Score
72/100
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Erythromycin Ethylsuccinate (brand names E.E.S. and EryPed) is an oral macrolide antibiotic used to treat a wide range of bacterial infections. It is an ester form of erythromycin, chemically modified to improve oral absorption and stability. It has been in clinical use since the 1950s and remains an important option for patients who are allergic to penicillin.
Erythromycin Ethylsuccinate is FDA-approved for upper and lower respiratory tract infections, skin and soft-tissue infections, chlamydial urethritis and cervicitis, pertussis (whooping cough), Legionnaire's disease, intestinal amebiasis, and long-term prophylaxis of rheumatic fever in penicillin-allergic patients.
It is available as film-coated tablets (400mg) and oral suspension (200mg/5mL and 400mg/5mL), with the suspension formulations intended primarily for pediatric use. Generic versions are widely available and manufactured by multiple companies including Amneal Pharmaceuticals and Carnegie Pharmaceuticals.
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Erythromycin Ethylsuccinate works by binding to the 50S ribosomal subunit of susceptible bacteria and inhibiting RNA-dependent protein synthesis. Bacteria need ribosomes to make proteins — without proteins, they cannot grow, divide, or maintain themselves. By blocking this process, erythromycin stops bacterial multiplication and gives the immune system time to clear the infection.
Erythromycin is primarily bacteriostatic (stops bacterial growth) rather than bactericidal (kills bacteria directly) at standard clinical doses. This is why completing the full prescribed course is important — stopping early allows surviving bacteria to resume multiplying before your immune system has fully cleared the infection.
Erythromycin is also a potent inhibitor of CYP3A4, the liver enzyme responsible for metabolizing approximately 50% of all medications. This mechanism underlies erythromycin's extensive drug interaction profile and requires careful medication reconciliation before prescribing or dispensing.
400 mg — film-coated tablet
Standard adult dosage form. Take 400mg every 6 hours (up to 4g/day for severe infections). Can be taken with or without food.
200 mg/5 mL — oral suspension
Pediatric suspension. Reconstituted from granules. For children: 30-50mg/kg/day in divided doses. Primarily for infants and young children.
400 mg/5 mL — oral suspension
Higher-concentration pediatric/adult suspension. Reconstituted from granules. Can be used in older children and adults who cannot swallow tablets.
Oral Erythromycin Ethylsuccinate is not on the FDA's official Drug Shortage List as of 2026 — but finding it at your local pharmacy can still be a challenge. Because prescribing volumes have declined significantly as newer macrolides (especially azithromycin) took over most of its indications, many chain pharmacies no longer routinely stock E.E.S. The suspension formulations are particularly difficult to find at large retail chains due to reconstitution and storage requirements.
Independent community pharmacies and warehouse pharmacies (Costco, Sam's Club) are more likely to stock or special-order E.E.S. Mail-order pharmacy is a good option for patients on ongoing prescriptions (such as rheumatic fever prophylaxis).
Rather than calling every pharmacy in your area, medfinder contacts pharmacies near you to check which ones have Erythromycin Ethylsuccinate in stock — then texts the results directly to you.
Erythromycin Ethylsuccinate is not a controlled substance, so any licensed prescriber can write a prescription without DEA registration requirements or special prescription forms. It is widely prescribed in primary care and pediatric settings.
Primary Care Physicians (family medicine, internal medicine)
Pediatricians
OB/GYNs (for chlamydial infections and pregnancy-related indications)
Infectious Disease Specialists
Nurse Practitioners (NPs) — in most states
Physician Assistants (PAs) — in most states
Urgent Care Providers
Erythromycin Ethylsuccinate is widely available via telehealth for appropriate outpatient infections. Because it is not a controlled substance, telehealth providers can prescribe it in most states without restrictions. Services like Teladoc, MDLive, and PlushCare can evaluate and prescribe E.E.S. for conditions like strep throat, skin infections, and chlamydia.
No. Erythromycin Ethylsuccinate is
not a controlled substance and has no DEA scheduling. It is a standard prescription antibiotic that any licensed healthcare provider can prescribe — including via telehealth in most states.
Because it is not a controlled substance, there are no restrictions on the number of refills (other than those imposed by the prescribing indication), no special prescription forms required, and no DEA-registered prescriber requirements. Nurse practitioners and physician assistants in most states can prescribe E.E.S. without restriction.
The most frequent side effects are gastrointestinal and are dose-related:
Nausea (most common)
Abdominal cramping and stomach pain
Diarrhea
Loss of appetite
Vomiting (less common)
QT prolongation / Torsades de pointes arrhythmia (palpitations, dizziness, fainting)
Cholestatic hepatitis / liver damage (jaundice, dark urine, upper right abdominal pain)
C. difficile-associated diarrhea (severe, watery, or bloody diarrhea during or weeks after treatment)
Ototoxicity / hearing loss (especially in elderly patients with renal/hepatic impairment)
Infantile hypertrophic pyloric stenosis in neonates under 6 weeks old
Allergic reactions (rash, hives, anaphylaxis)
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Azithromycin (Zithromax, Z-Pak)
Newer macrolide with once-daily dosing and 5-day courses. Better GI tolerability, fewer drug interactions (no CYP3A4 inhibition), and wider availability. First-line substitute for most E.E.S. indications.
Clarithromycin (Biaxin)
Macrolide with twice-daily dosing. Stronger activity against some resistant strains. Used for respiratory infections and H. pylori. Has similar CYP3A4 interaction profile to erythromycin.
Amoxicillin
Beta-lactam antibiotic. First-line for strep throat and respiratory infections in non-penicillin-allergic patients. Not appropriate for penicillin-allergic patients.
Doxycycline
Tetracycline antibiotic effective for chlamydia (CDC preferred for non-pregnant adults), atypical pathogens, and respiratory infections. Avoid in pregnant women and children under 8.
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Pimozide
majorAbsolutely contraindicated — erythromycin inhibits CYP3A4 metabolism of pimozide, causing dangerous QT prolongation and risk of fatal arrhythmia.
Cisapride
majorAbsolutely contraindicated — risk of QT prolongation and ventricular arrhythmia.
Colchicine
majorPotentially life-threatening colchicine toxicity even at normal doses of both drugs. Avoid combination; hold colchicine during erythromycin course.
Lovastatin / Simvastatin
majorSignificantly elevated statin levels — risk of myopathy and rhabdomyolysis. Hold the statin during erythromycin treatment when possible.
Ergotamine / Dihydroergotamine
majorRisk of acute ergot toxicity with severe vasospasm and ischemia. Avoid combination.
Warfarin
moderateEnhanced anticoagulation effect — monitor INR closely during and after erythromycin course.
Digoxin
moderateElevated digoxin serum levels — monitor for digoxin toxicity.
Theophylline
moderateReduced theophylline clearance — elevated levels with risk of theophylline toxicity. Monitor serum levels.
Cyclosporine / Tacrolimus
moderateElevated immunosuppressant levels — risk of nephrotoxicity. Monitor drug levels and kidney function.
Carbamazepine
moderateElevated carbamazepine levels — risk of toxicity including dizziness, double vision, and ataxia.
Erythromycin Ethylsuccinate is one of the oldest antibiotics still in use and remains clinically relevant in 2026 — particularly for penicillin-allergic patients, children requiring pediatric suspension formulations, and patients on long-term rheumatic fever prophylaxis. While newer macrolides like azithromycin have taken over most of its routine uses, E.E.S. occupies an important niche that makes it worth knowing how to access.
The main access challenge is pharmacy stocking — not an official shortage. Independent pharmacies, mail-order services, and compounding pharmacies are your best bets when chain pharmacies don't have it. E.E.S. is affordable with a discount coupon or insurance, and patient assistance programs are available for those who qualify. Its extensive drug interaction profile and GI side effect burden are important considerations when prescribing.
If you're having trouble finding Erythromycin Ethylsuccinate at your local pharmacy, medfinder can help. Enter your medication, dosage, and location — medfinder contacts pharmacies near you and texts you the results.
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