What antibiotic drops are recommended for treating conjunctivitis?

Antibiotic Eye Drops for Conjunctivitis

For bacterial conjunctivitis, use topical moxifloxacin 0.5% one drop three times daily for 5-7 days as first-line therapy, as it provides superior gram-positive coverage including activity against common pathogens and some MRSA strains. 1, 2

Treatment Algorithm by Etiology

Bacterial Conjunctivitis (Mild to Moderate)

First-Line Options:

• Moxifloxacin 0.5%: One drop three times daily for 7 days 1, 2
  • Superior gram-positive coverage including S. aureus, S. pneumoniae, H. influenzae, and some MRSA strains 1, 3
  • Microbiological eradication rates of 84-94% 1
  • Also effective against Chlamydia trachomatis 3, 2

Alternative Fluoroquinolones (if moxifloxacin unavailable):

• Gatifloxacin 0.5%: Day 1 every 2 hours while awake (up to 8 times), then Days 2-7 two to four times daily 1, 4
• Levofloxacin 0.5%: Demonstrated 89% microbial eradication vs. 80% with ofloxacin 5
• Ofloxacin 0.3%: Four times daily for 5-7 days (second-line, lower eradication rates) 1, 5

Second-Line Options (when fluoroquinolones unavailable or cost-prohibitive):

• Gentamicin, tetracycline, or polymyxin B/trimethoprim 1, 6
• Povidone-iodine 1.25% ophthalmic solution may be as effective as topical antibiotics 6

Severe Bacterial Conjunctivitis

Clinical Features: Copious purulent discharge, pain, marked inflammation 1

Management:

• Obtain conjunctival cultures and Gram staining BEFORE initiating treatment 1, 6
• Consider loading dose: One drop every 5-15 minutes, then hourly applications 3
• Suspect gonococcal or chlamydial infection if severe 1

Gonococcal Conjunctivitis (REQUIRES SYSTEMIC THERAPY)

Critical: Topical antibiotics alone are INSUFFICIENT 1, 6

Treatment:

• Adults: Ceftriaxone 250 mg IM single dose PLUS azithromycin 1 g oral single dose 1
• Neonates: Ceftriaxone 25-50 mg/kg IV or IM single dose 1
• Daily monitoring until resolution is mandatory 1
• Immediate ophthalmology referral required 1

Chlamydial Conjunctivitis (REQUIRES SYSTEMIC THERAPY)

Critical: Topical therapy alone is insufficient; >50% of infants have infection at other sites 1, 6

Treatment:

• Adults: Azithromycin 1 g oral single dose OR doxycycline 100 mg oral twice daily for 7 days 1
• Neonates: Erythromycin base or ethylsuccinate 50 mg/kg/day oral divided into 4 doses for 14 days 1
• Children ≥45 kg but <8 years: Azithromycin 1 g oral single dose 1
• Children ≥8 years: Azithromycin 1 g oral single dose OR doxycycline 100 mg oral twice daily for 7 days 1

Viral Conjunctivitis (NO ANTIBIOTICS)

Management:

• Supportive care ONLY: Refrigerated preservative-free artificial tears four times daily and cold compresses 1
• Avoid antibiotics - no benefit and promotes resistance 1, 7
• For HSV conjunctivitis: Topical ganciclovir 0.15% gel OR trifluridine 1% solution PLUS oral antivirals (acyclovir, valacyclovir, or famciclovir) 1
• Never use topical corticosteroids in HSV without antiviral coverage - potentiates infection 1

Allergic Conjunctivitis (NO ANTIBIOTICS)

Management:

• Second-generation topical antihistamines with mast-cell stabilizing properties as first-line 1
• Cold compresses, refrigerated artificial tears, sunglasses 1
• Avoid antibiotics - no benefit 1

Critical Red Flags Requiring Immediate Ophthalmology Referral

• Visual loss 1
• Moderate or severe pain 1
• Severe purulent discharge 1
• Corneal involvement (infiltrate, ulcer, opacity) 1
• Conjunctival scarring 1
• Lack of response after 3-4 days of appropriate therapy 1, 6
• History of HSV eye disease 1
• Immunocompromised state 1
• Neonatal conjunctivitis (requires systemic treatment) 1

Special Populations

Contact Lens Wearers:

• Higher risk for Pseudomonas infection - use fluoroquinolones 6
• Advise discontinuation of contact lens use during treatment 1

Pediatric Patients:

• Fluoroquinolones (moxifloxacin, levofloxacin, gatifloxacin, ciprofloxacin, besifloxacin) approved for children >12 months 1

Suspected MRSA:

• Consider compounded topical vancomycin if fluoroquinolones fail 1
• MRSA isolates generally resistant to fluoroquinolones and aminoglycosides but susceptible to vancomycin 1

Common Pitfalls to Avoid

• Using antibiotics for viral conjunctivitis - promotes resistance and provides no benefit 1, 7
• Using topical corticosteroids in HSV without antiviral coverage - potentiates infection 1
• Treating gonococcal or chlamydial conjunctivitis with topical antibiotics alone - systemic therapy is mandatory 1, 6
• Failing to consider sexual abuse in children with gonococcal or chlamydial conjunctivitis 1
• Ignoring local resistance patterns - fluoroquinolone resistance varies geographically 1, 3
• Not obtaining cultures in severe cases - delays appropriate therapy 1, 6

Infection Control

• Strict hand hygiene with soap and water 1
• Avoid close contact for 7-14 days in viral conjunctivitis 1
• Discard multiple-dose eyedrop containers to avoid cross-contamination 1
• Separate towels and avoid eye rubbing 6