Erythromycin

Selected oral and IV labels cover susceptible respiratory, skin, and other infections, including streptococcal infections, Mycoplasma pneumoniae, pertussis, diphtheria as an adjunct to antitoxin or for carrier eradication, erythrasma, listeriosis, intestinal amebiasis, and Legionella infections. Haemophilus influenzae respiratory indications require the label-specified sulfonamide combination; erythromycin alone is not dependable coverage. Oral labels also describe rheumatic-fever prevention when penicillin cannot be used. Treat only proven or strongly suspected susceptible bacterial disease, considering cultures and local resistance. IV treatment is reserved for cases in which oral administration is not possible or immediate high serum levels are needed.

Older systemic labels retain chlamydial, syphilis, and gonococcal PID indications/regimens. Current CDC guidance no longer recommends erythromycin for adult/pregnancy chlamydia because GI intolerance can impair adherence; its current PID regimens do not include erythromycin. CDC specifically advises against erythromycin for syphilis during pregnancy because it does not reliably cure maternal infection or treat the fetus. These legacy label regimens are not promoted here. Neonatal chlamydial systemic treatment remains a separate CDC-supported use.

The 2% skin gel is labeled for acne vulgaris. The 0.5% ophthalmic ointment treats susceptible superficial conjunctival/corneal infection and is used for neonatal gonococcal prophylaxis. Although the eye label also mentions chlamydial prophylaxis, CDC states erythromycin eye prophylaxis is ineffective against chlamydial infection; neonatal chlamydial disease needs systemic treatment. Skin gel is not an eye medicine.

These are general label regimens, not a universal course for every organism/site. Infection-specific duration and susceptibility must be selected separately. The base tablet is film-coated, not the delayed-release ERY-TAB product.

Base tablets may be taken with or without food, but optimal blood concentrations occur fasting, at least 30 minutes and preferably 2 hours before meals. E.E.S. may be taken without regard to meals. For ADULT conversion, the E.E.S. label states 400 mg ethylsuccinate activity corresponds to 250 mg base/stearate/estolate activity; this is not a pediatric conversion rule. For the selected E.E.S. 200 mg/5 mL granules, add 77 mL water for a 100 mL bottle or 154 mL for a 200 mL bottle and shake vigorously; measure the prescribed volume accurately.

For severe infection in adults and children, the IV label gives 15–20 mg/kg/day; severe infections may require up to 4 g/day. IV therapy should transition to oral therapy when appropriate. Continuous infusion is preferred at 1 mg/mL; intermittent infusion uses one-fourth of the daily dose at intervals no longer than 6 hours, at 1–5 mg/mL in at least 100 mL, infused over 20–60 minutes. Never give IV push or intramuscularly. Reconstitute the 500 mg vial with 10 mL sterile water only; do not use saline, bacteriostatic water, or other diluents for initial reconstitution. The current label lists 0.9% sodium chloride, lactated Ringer’s, or Normosol-R for further dilution. Follow its exact compatibility/preparation instructions.

Gel: apply a thin film to cleaned, gently dried affected skin once or twice daily; spread lightly rather than rub. If worsening or no improvement after 6–8 weeks, stop and consult the clinician. For acne antibiotic therapy, AAD recommends concurrent benzoyl peroxide to limit resistance; this is guidance, not a fixed-dose product instruction. Eye infection: apply approximately a 1 cm ribbon into the infected eye up to 6 times daily according to severity. For neonatal gonococcal prophylaxis, CDC recommends 0.5% ointment once in both eyes at birth, ideally within 24 hours; use a new tube for each infant and do not flush it out.

CDC’s neonatal chlamydial conjunctivitis/pneumonia regimen is oral erythromycin base or ethylsuccinate 50 mg/kg/day divided into 4 doses for 14 days, with follow-up for response and pyloric-stenosis symptoms. Topical eye treatment alone is inadequate for chlamydial ophthalmia; gonococcal disease also needs systemic treatment. The older IV label’s endocarditis dental prophylaxis scheme does not match the current AHA wallet card, whose listed regimens do not include erythromycin; no legacy dental prophylaxis dose is supplied here.

All selected products are contraindicated after hypersensitivity to erythromycin or their ingredients. Systemic labels contraindicate combinations with terfenadine, astemizole, cisapride, pimozide, ergotamine/dihydroergotamine, and lovastatin/simvastatin; some prohibitions appear in interaction sections as well as the formal list. The topical and eye labels do not list these systemic combinations as their own formal contraindications. QT-risk avoidance belongs to warnings, not a fabricated additional contraindication list.

None of these selected U.S. labels contains a boxed warning. Systemic arrhythmia and interaction warnings still require active screening.

Oral treatment commonly causes dose-related nausea, vomiting, abdominal pain, or diarrhea; reversible hearing loss occurs particularly with high exposure and renal/hepatic impairment. IV treatment can cause venous irritation. Gel causes burning, dryness, peeling, redness, or itching; eye ointment can cause mild irritation, redness, or allergy. Serious allergic/skin/hepatic reactions require discontinuation and assessment. Systemic overdose requires stopping treatment and supportive management; hemodialysis or peritoneal dialysis does not remove erythromycin. Local-product ingestion or significant eye/skin reactions requires product-specific assessment rather than an invented antidote.

Avoid the systemic contraindicated combinations listed in Safety. Colchicine toxicity can be life-threatening; follow its own organ-function and inhibitor restrictions. Atorvastatin exposure/myopathy risk also requires review, although it is not identical to the formal lovastatin/simvastatin prohibition. Calcium-channel blockers such as verapamil, diltiazem, and amlodipine can produce hypotension; triazolam/midazolam can cause greater/prolonged sedation. Review additive QT drugs and antiarrhythmics before prescribing.

Systemic labels describe increased concentrations/effects of medicines including theophylline, digoxin, carbamazepine, phenytoin, valproate, cyclosporine/tacrolimus, and oral anticoagulants; obtain clinically appropriate levels or INR and adjust the affected medicine as needed. Sildenafil exposure may rise and its own dosing guidance applies. These are medication-specific actions, not a universal erythromycin dose reduction. Gel labeling cautions about additive irritation from other peeling/abrasive topical acne agents; local-label evidence does not establish the full systemic interaction profile for eye or skin use.

Systemic labels describe limited controlled human pregnancy data and advise use only when clearly needed; some oral labels note observational cardiovascular-malformation associations without establishing causation. Erythromycin does not reliably treat fetal syphilis. Systemic erythromycin is present in breast milk and labeling advises caution. Gel and eye labels also advise individualized pregnancy/lactation assessment; systemic absorption/milk effects after topical gel are not established. These summaries reflect the selected labels, not a claim of zero infant risk.

Systemic labels contain pediatric dosing; neonatal use requires the indication-specific regimen, weight assessment, and pyloric-stenosis surveillance. Gel safety/effectiveness in pediatric patients has not been established by its label; the AAD guidance is not an FDA-approved pediatric age for this product. Older systemic-treatment patients need attention to QT risk, interactions, hearing effects, and organ function. Eye prophylaxis in newborns has a distinct route and purpose.

Erythromycin is concentrated in the liver and excreted mainly in bile; use systemic therapy cautiously with impaired hepatic function. High-dose systemic treatment and renal/hepatic dysfunction increase hearing-toxicity concerns. The selected labels do not supply one complete quantitative renal/hepatic adjustment algorithm for all formulations; do not invent one. Dialysis does not remove systemic drug. Local gel and eye labels do not establish separate numerical organ-impairment regimens.

Erythromycin binds the bacterial 50S ribosomal subunit and inhibits protein synthesis. Resistance and cross-resistance can compromise activity; susceptibility and site of infection determine suitability. Acne gel’s mechanism is not fully characterized by its label. Do not assume activity against every organism on the historical indication list without contemporary susceptibility assessment.

Oral base and ethylsuccinate have formulation-dependent absorption: base reaches optimal concentrations fasting, whereas ethylsuccinate achieves comparable levels with or without meals. Systemic erythromycin distributes widely, with low CSF penetration absent meningeal inflammation, and undergoes predominantly biliary elimination. Less than 5% of oral drug and about 12–15% of IV drug are recovered active in urine. The local labels do not provide a comparable systemic exposure or elimination model, so oral/IV measurements are not assigned to gel or ophthalmic treatment.

Confirm indication, allergy, cultures/susceptibility when appropriate, current treatment guidance, and medication interactions. For systemic therapy assess hepatic/renal function, electrolyte/QT risk, hearing symptoms at high exposure, and indicated drug levels or INR; ECG/laboratory frequency depends on risk and treatment. Check IV site and preparation compatibility. Follow skin/eye response and overgrowth; neonatal chlamydial disease requires follow-up after the course. No label establishes a universal monitoring interval.

Take only the prescribed route and complete the indicated course; do not save/share antibiotics. Report fainting/palpitations, jaundice, hearing changes, severe rash, or persistent watery/bloody diarrhea promptly. Caregivers should seek assessment for infant vomiting or feeding irritability. Shake and accurately measure suspension. Keep gel away from eyes and flames, and avoid contaminating the ophthalmic tube tip. Reassess acne if worsening or unimproved after 6–8 weeks.

Torrent base tablets: 250 mg white/off-white oval AC412 and 500 mg AC413; representative 30-count NDCs 13668-606-30 and 13668-607-30. Carnegie E.E.S. 400 mg tablets are pink oval marked EE; 200 mg/5 mL granules are supplied for 100 or 200 mL bottles. Hospira IV product is a 500 mg vial, NDC 0409-6482-01. Padagis gel is supplied in 30 g or 60 g tubes. The selected ophthalmic record is RemedyRepack’s 3.5 g repackaged tube, NDC 70518-0465-00, not a claim that it is the original manufacturer’s package.

Covered products are non-enteric film-coated base tablets 250/500 mg, E.E.S. ethylsuccinate granules 200 mg/5 mL after mixing and 400 mg tablets, lactobionate injection 500 mg/vial for IV infusion, skin gel 2% (20 mg/g), and ophthalmic ointment 0.5% (5 mg/g). Delayed-release tablets, stearate/estolate products, other suspension packages, combination products, and off-label prokinetic regimens require separate review and are outside this reference.

Base tablets and unopened IV vials: 20–25°C; base-tablet excursions 15–30°C. E.E.S. granules/tablets: below 30°C before mixing; refrigerate mixed suspension and use within 10 days. IV reconstituted stock is stable for 24 hours at room temperature or 2 weeks refrigerated; administer the final diluted infusion within 8 hours and discard unused single-vial contents. Gel: 20–25°C, keep original tube tightly closed, away from heat/open flame because it is flammable. Selected eye ointment: 15–25°C. Inspect IV solution for particles/discoloration and protect sterile eye-tube tips from contact.