What are examples of antibiotic eye drops for treating bacterial eye infections?

Antibiotic Eye Drop Examples

For bacterial conjunctivitis, use moxifloxacin 0.5% or gatifloxacin 0.5% as first-line agents, as these fourth-generation fluoroquinolones provide superior gram-positive coverage compared to older fluoroquinolones. 1, 2, 3

FDA-Approved Fluoroquinolones

Fourth-Generation (Preferred)

• Moxifloxacin 0.5% - Instill one drop in the affected eye 3 times daily for 7 days 2
• Gatifloxacin 0.5% - Day 1: one drop every 2 hours while awake (up to 8 times); Days 2-7: one drop 2-4 times daily 3
• Both agents demonstrate better gram-positive pathogen coverage than earlier generation fluoroquinolones in head-to-head in vitro studies 4, 1

Earlier Generation Options

• Levofloxacin 1.5% - FDA-approved with equal efficacy to ofloxacin 0.3% 4
• Ciprofloxacin 0.3% - FDA-approved for bacterial keratitis 4
• Ofloxacin 0.3% - FDA-approved for bacterial keratitis 4

Severe Infections or Treatment Failures

For Suspected MRSA

• Vancomycin (fortified) - Fluoroquinolones are generally poorly effective against MRSA ocular isolates, with methicillin resistance found in 42% of staphylococcal isolates 4, 1, 5
• Topical linezolid can be used for vancomycin-resistant enterococcus 4

For Resistant Pseudomonas

• Topical colistin 0.19% - Consider for multidrug-resistant Pseudomonas aeruginosa 4, 1
• Note: Sharp increase in Pseudomonas resistance to moxifloxacin has been documented (19% in 2007 to 52% in 2009 in southern India) 4

Fortified Combination Therapy

• Fortified cefazolin/tobramycin - Alternative for severe infections, especially with deep stromal involvement or infiltrates >2mm with extensive suppuration 4
• Should be prepared by FDA-designated 503A and/or 503B compounding pharmacy 4

Special Considerations

Resistance Patterns

• Increasing overall resistance to fluoroquinolones has been observed from 1996 to 2015 4, 5
• Risk factors for fluoroquinolone resistance include recent fluoroquinolone use, hospitalization, and recent ocular surgery 4, 1
• Some pathogens (Streptococci, anaerobes) have variable susceptibility to fluoroquinolones 4

Specific Pathogens

• Gonococcal keratitis - Requires systemic antibiotic therapy in addition to topical treatment 4, 1, 5
• Moraxella keratitis - Usually susceptible to fluoroquinolones and aminoglycosides but requires prolonged treatment duration (mean 41.9 days) 4

Common Pitfalls to Avoid

• Do not use contact lenses during treatment if signs or symptoms of bacterial conjunctivitis are present 2, 3
• Avoid topical corticosteroids until infection has been ruled out, as they can mask signs of infection 6
• Prolonged use may result in overgrowth of non-susceptible organisms including fungi 2, 3
• If no improvement after 7 days, reevaluate diagnosis and consider alternative treatment 5, 6