Erythromycin Ophthalmic Ointment: Dosage and Usage
For superficial ocular infections, apply approximately 1 cm of erythromycin 0.5% ophthalmic ointment directly to the infected eye(s) up to 6 times daily depending on infection severity. 1
Specific Indications and Dosing
Superficial Ocular Infections
- Apply 1 cm ribbon of ointment to the conjunctiva and/or cornea for infections caused by erythromycin-susceptible organisms 1
- Frequency ranges from 1-6 times daily based on severity 1
- Effective for conjunctival and corneal infections involving susceptible bacteria 1
Anterior Blepharitis
- Apply to eyelid margins one or more times daily or at bedtime for several weeks 2
- Can be repeated intermittently using different antibiotics to prevent resistance development 2
- Duration should be guided by severity and clinical response 2
Neonatal Prophylaxis
- Instill 1 cm ribbon into each lower conjunctival sac as a single application for prevention of ophthalmia neonatorum due to N. gonorrhoeae or C. trachomatis 1
- Do not flush the ointment from the eye after instillation 1
- Use a new tube for each infant 1
- Required by law in most states for all newborns, regardless of delivery method 2
Important Clinical Limitations
When Ointments Are Suboptimal
- Ointments lack adequate corneal penetration for severe bacterial keratitis due to poor solubility 2
- For central or severe keratitis (>2 mm infiltrate, deep stromal involvement, hypopyon), use topical antibiotic drops instead, such as fluoroquinolones 2
- Ointments may be useful as adjunctive bedtime therapy in less severe cases 2
Prophylaxis Limitations
- Effectiveness against penicillinase-producing N. gonorrhoeae is not established 1
- For infants born to mothers with clinically apparent gonorrhea, systemic penicillin G is required (50,000 units IM/IV for term infants); topical prophylaxis alone is inadequate 1
Common Pitfalls to Avoid
- Do not rely on ointment monotherapy for bacterial keratitis requiring aggressive treatment—drops achieve superior corneal tissue levels 2
- Avoid prolonged continuous use as this promotes antibiotic resistance and can cause medication toxicity 2
- When tapering antibiotics for keratitis, do not reduce below 3-4 times daily as subtherapeutic dosing increases resistance risk 2
- For persistent epithelial defects with controlled infection, add surface rehabilitation measures (lubrication, bandage contact lens, amniotic membrane) rather than continuing high-frequency antibiotics 2