What medication is used to treat bacterial conjunctivitis?

Treatment of Bacterial Conjunctivitis

For mild bacterial conjunctivitis, prescribe a broad-spectrum topical antibiotic (such as moxifloxacin, gentamicin, ofloxacin, or polymyxin B/trimethoprim) applied 4 times daily for 5-7 days. 1, 2

First-Line Treatment Approach

• Topical antibiotics are recommended even for mild cases because they accelerate clinical and microbiological remission by days 2-5, reduce transmissibility, and allow earlier return to school or work compared to no treatment 1, 2

• Choose the most convenient or least expensive broad-spectrum option, as no clinical evidence demonstrates superiority of any particular antibiotic for uncomplicated cases 2

• Recommended first-line agents include:

  • Fluoroquinolones: moxifloxacin 0.5% or ofloxacin 1, 3
  • Aminoglycosides: gentamicin or tobramycin 1
  • Combination agents: polymyxin B/trimethoprim 1
  • Tetracycline ointment 1

Specific Antibiotic Dosing

• Moxifloxacin 0.5%: Instill 1 drop in affected eye 3 times daily for 7 days 3

• Standard broad-spectrum antibiotics: Apply 4 times daily for 5-7 days 2

• Moxifloxacin is FDA-approved for bacterial conjunctivitis caused by susceptible organisms including S. aureus, S. pneumoniae, H. influenzae, and C. trachomatis 3

Moderate to Severe Cases

• Obtain conjunctival cultures and Gram staining before initiating treatment if you observe copious purulent discharge, severe pain, or marked inflammation 1, 2

• Consider compounded fortified antibiotics (such as vancomycin) for suspected MRSA infections 1, 2

• Follow up in 3-4 days if no improvement to reassess and adjust therapy 1

Special Situations Requiring Systemic Therapy

Gonococcal Conjunctivitis

• Requires systemic antibiotics—topical therapy alone is insufficient 1, 2
• Add saline lavage for comfort and faster resolution 1
• Daily follow-up until resolution 2
• Consider hospitalization for severe cases; mandatory for neonates 1

Chlamydial Conjunctivitis

• Requires systemic antibiotics, not topical therapy 1, 2
• For neonates: erythromycin base or ethylsuccinate 50 mg/kg/day divided into 4 doses for 14 days (clinical cure rate 96%, microbiological cure 97%) 1
• Especially important in infants who may have infection at other sites 1, 2
• Follow-up is critical as treatment failure occurs in up to 19% of cases 2

MRSA Conjunctivitis

• May require vancomycin (compounded topical preparation) 1, 2

Alternative When Antibiotics Are Limited

• Povidone-iodine 1.25% ophthalmic solution may be as effective as topical antibiotics and can be considered when access to antibiotics is limited 1, 2

Critical Pitfalls to Avoid

• Do not use topical antibiotics alone for gonococcal or chlamydial conjunctivitis—these require systemic therapy 1, 2

• Advise patients not to wear contact lenses during treatment 3

• In children with gonococcal or chlamydial conjunctivitis, consider the possibility of sexual abuse 1, 2

• Be aware of increasing bacterial resistance, particularly MRSA 1, 2

• Poor adherence to frequent dosing regimens contributes to treatment failure 1

When to Refer to Ophthalmology

• Refer immediately if patient has: 1

  • Visual loss
  • Moderate or severe pain
  • Severe purulent discharge
  • Corneal involvement
  • Conjunctival scarring
  • Lack of response to therapy after 3-4 days
  • Recurrent episodes

• Perform interval visual acuity and slit-lamp examination at follow-up visits 1

• If severe inflammation persists, a brief course of topical corticosteroids may be indicated, but monitor intraocular pressure 1