Drug class: Antibacterials
CAS number: 114-07-08

Medically reviewed by Drugs.com on Jul 20, 2023. Written by ASHP.

Introduction

Antibacterial; macrolide antibiotic.

Uses for Erythromycin (EENT)

Bacterial Ophthalmic Infections

Topical treatment of superficial infections of the eye involving the conjunctiva and/or cornea caused by susceptible bacteria.

Mild, acute bacterial conjunctivitis often resolves spontaneously without anti-infective treatment. Although topical ophthalmic anti-infectives may shorten time to resolution and reduce severity and risk of complications, avoid indiscriminate use of topical anti-infectives.

Treatment of acute bacterial conjunctivitis generally is empiric; use of a broad-spectrum topical ophthalmic antibacterial usually recommended. In vitro staining and/or cultures of conjunctival material indicated in diagnosis and management of all cases of suspected infectious conjunctivitis in neonates, all cases of suspected gonococcal or chlamydial conjunctivitis, and may be indicated in management of recurrent, severe, or chronic purulent conjunctivitis or when acute conjunctivitis does not respond to initial empiric topical treatment.

Bacterial conjunctivitis caused by Neisseria gonorrhoeae requires treatment with systemic anti-infectives (e.g., IM or IV ceftriaxone) with or without topical anti-infectives. Topical anti-infectives alone are inadequate for treatment of ophthalmia neonatorum caused by N. gonorrhoeae; some experts state that adjunctive use of topical anti-infectives unnecessary when appropriate systemic anti-infectives used.

Chlamydial Ophthalmic Infections

Has been used topically in the treatment of conjunctivitis secondary to trachoma caused by Chlamydia trachomatis^{† [off-label]}; however, systemic anti-infectives (usually oral azithromycin) are recommended for treatment of ocular trachoma.

Systemic anti-infectives (e.g., oral azithromycin, doxycycline, or erythromycin) are necessary for treatment of chlamydial conjunctivitis, including chlamydial ophthalmia neonatorum. Experts state that topical anti-infectives alone are inadequate for treatment of chlamydial ophthalmic infections and are unnecessary when appropriate systemic anti-infectives used.

Has been used for topical prophylaxis of ophthalmia neonatorum caused by C. trachomatis. However, efficacy of topical prophylaxis for prevention of chlamydial neonatal conjunctivitis not established. Experts state that erythromycin used for topical prophylaxis of gonococcal ophthalmia neonatorum will not prevent chlamydial ophthalmia neonatorum.

Prophylaxis of Gonococcal Ophthalmia Neonatorum

Topical prophylaxis of ophthalmia neonatorum caused by N. gonorrhoeae. Efficacy for prevention of ophthalmia neonatorum caused by penicillinase-producing N. gonorrhoeae not established.

CDC and AAP recommend topical erythromycin prophylaxis in all neonates as soon as possible after birth (regardless of whether they are delivered vaginally or by cesarean section); such prophylaxis required by law in most states. Although silver nitrate and tetracycline have been used in the past for topical prophylaxis of gonococcal ophthalmia neonatorum, ophthalmic preparations of these drugs no longer commercially available in the US.

If erythromycin ophthalmic ointment not available, CDC recommends systemic prophylaxis with a single dose of ceftriaxone (IM or IV) for all neonates at risk for exposure to N. gonorrhoeae (especially those born to women who are at risk for gonococcal infection or received no prenatal care).

Infants born to women with untreated gonorrhea are at high risk of infection; CDC and AAP recommend that such neonates receive systemic prophylaxis with a single dose of ceftriaxone (IM or IV) instead of topical erythromycin prophylaxis.

Erythromycin (EENT) Dosage and Administration

Administration

Ophthalmic Administration

Apply 0.5% ophthalmic ointment topically to the eye.

For topical ophthalmic use only.

Avoid contaminating tip of ointment tube with material from eye, fingers, or other source.

When used for prophylaxis of gonococcal ophthalmia neonatorum, place specified amount of ointment into each of neonate’s lower conjunctival sacs and massage gently to spread ointment; after 1 minute, wipe away excess ointment with sterile cotton. Do not flush ointment from the eye following application. Use a new tube or single-use container of ointment for each neonate.

Dosage

Pediatric Patients

Bacterial Ophthalmic Infections

Ophthalmic

Apply 1-cm ribbon of 0.5% ointment to the affected eye(s) up to 6 times daily. For empiric treatment of acute bacterial conjunctivitis, experts recommend application 4 times daily for 1 week.

Prophylaxis of Gonococcal Ophthalmia Neonatorum

Ophthalmic

Place 1-cm ribbon of 0.5% ointment into lower conjunctival sac of both eyes.

Administer as soon as possible (within 1 hour) after birth. Efficacy unlikely to be affected if topical prophylaxis delayed for up to 1 hour after delivery (e.g., to facilitate parent-infant bonding); efficacy of prophylaxis administered after a longer delay not studied.

Adults

Bacterial Ophthalmic Infections

Ophthalmic

Apply 1-cm ribbon of 0.5% ointment to the affected eye(s) up to 6 times daily. For empiric treatment of acute bacterial conjunctivitis, experts recommend application 4 times daily for 1 week.

Cautions for Erythromycin (EENT)

Contraindications

• Hypersensitivity to erythromycin.

Warnings/Precautions

Sensitivity Reactions

Hypersensitivity

Possible sensitivity reactions.

General Precautions

Superinfection

Prolonged use may result in overgrowth of nonsusceptible organisms, including fungi.

If superinfection occurs, discontinue and institute appropriate therapy.

Specific Populations

Pregnancy

Data not available regarding use in pregnant women. Use only if clearly needed.

Lactation

Use with caution in nursing women.

Pediatric Use

See Uses.

Geriatric Use

No overall differences in safety or efficacy compared with younger patients.

Common Adverse Effects

Minor ocular irritation, redness, hypersensitivity.

Erythromycin (EENT) Pharmacokinetics

Absorption

Extent

Topical application to the eye probably does not produce significant antibacterial concentrations in deep layers of cornea or in aqueous humor.

Not known whether erythromycin is absorbed to any substantial extent from mucous membranes.

Stability

Storage

Ophthalmic

Ointment

15–25°C.

Do not expose to excessive heat; do not freeze.

Actions and Spectrum

• Usually bacteriostatic; may be bactericidal in high concentrations or against highly susceptible organisms.

• Inhibits protein synthesis in susceptible organisms by binding to 50S ribosomal subunits.

• Gram-positive bacteria: Active in vitro and in clinical infections against Staphylococcus aureus (methicillin-susceptible strains only), Streptococcus pneumoniae, S. pyogenes (group A β-hemolytic streptococci; GAS), viridans streptococci (α-hemolytic streptococci), and Corynebacterium diphtheriae.

• Gram-negative bacteria: Active in vitro and in clinical infections against some strains of Haemophilus influenzae and Neisseria gonorrhoeae.

• Active against Chlamydia trachomatis and Mycoplasma pneumoniae. Also has activity against Treponema pallidum.

Advice to Patients

• Advise patients to avoid contaminating tip of ointment tube with material from the eye, fingers, or other source.

• Advise patients to immediately discontinue erythromycin ophthalmic ointment and contact a clinician at first sign of hypersensitivity reaction.

• Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses.

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.

• Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

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