Polymyxin B-Trimethoprim for Bacterial Conjunctivitis Treatment
Polymyxin B-trimethoprim ophthalmic solution is indicated as a first-line treatment for bacterial conjunctivitis, administered as 1 drop four times daily for 5-7 days. 1, 2, 3
Indications and Efficacy
Polymyxin B-trimethoprim ophthalmic solution is FDA-approved for:
- Acute bacterial conjunctivitis
- Blepharoconjunctivitis
It is effective against common ocular pathogens including:
- Staphylococcus aureus
- Staphylococcus epidermidis
- Streptococcus pneumoniae
- Streptococcus viridans
- Haemophilus influenzae
- Pseudomonas aeruginosa (limited data) 2, 3
Treatment Protocol
- Dosage: 1 drop in the affected eye(s) four times daily 4, 5
- Duration: 5-7 days 1
- Expected response: Clinical improvement typically occurs within 3-6 days, with complete resolution in most cases by 7-10 days 6, 7
Clinical Considerations
Efficacy Comparison
While polymyxin B-trimethoprim is effective, newer fluoroquinolones like moxifloxacin may provide faster symptom resolution:
- Moxifloxacin shows complete resolution in 81% of patients by 48 hours vs. 44% with polymyxin B-trimethoprim 4
- However, final cure rates at 7-10 days are similar between polymyxin B-trimethoprim (96%) and moxifloxacin (95%) 7
Cost-Effectiveness
- Polymyxin B-trimethoprim offers significant cost savings compared to fluoroquinolones with similar final clinical outcomes 7
- This makes it an excellent first-line choice for uncomplicated bacterial conjunctivitis
Adjunctive Measures
- Warm compresses to soften discharge and loosen crusts 1
- Proper hygiene measures to prevent spread:
- Frequent handwashing
- Separate towels and washcloths
- Avoiding sharing pillowcases
- Proper disinfection of toys and surfaces 1
When to Refer to an Ophthalmologist
Refer patients with:
- No response to therapy after 3-4 days
- Moderate to severe pain
- Decreased vision
- Corneal involvement
- Recurrent episodes
- History of herpes simplex virus eye disease
- Immunocompromised status 1
Special Populations
For neonatal conjunctivitis:
- Consider specific pathogens based on time of onset:
- 1-7 days: Possible gonococcal infection
- 5-19 days: Possible chlamydial infection
- First week: Common bacterial pathogens (S. aureus, Enterococcus, Klebsiella, E. coli)
- These may require different antibiotic choices and systemic therapy 1
Polymyxin B-trimethoprim is a well-established, effective, and economical first-line treatment for bacterial conjunctivitis, with high cure rates comparable to newer, more expensive alternatives when used for a complete treatment course.