Treatment Duration for Neo Poly Bac (Neomycin-Polymyxin B) for Stye
Neo Poly Bac ophthalmic ointment should be applied 3-4 times daily for 7-10 days for treatment of a stye (hordeolum), which is a localized bacterial skin and soft tissue infection of the eyelid.
Rationale for Duration
Styes are classified as uncomplicated skin and soft tissue infections (SSTIs), for which the standard treatment duration is 7-14 days 1
For most bacterial SSTIs, 7-10 days of antibiotic therapy is adequate for uncomplicated cases, with extension to 14 days reserved for infections that have not improved after 5 days 1
Recent evidence supports shorter courses (5-7 days) for uncomplicated cellulitis and similar superficial infections, though styes involving the eyelid margin may warrant the full 7-10 day course given the sensitive anatomical location 1
Application Guidelines
Apply the ointment directly to the affected eyelid margin 3-4 times daily, as this frequency has been shown effective in ophthalmic formulations containing neomycin 3.5 mg and polymyxin B 10,000 units per gram 2
The combination of neomycin and polymyxin B provides synergistic antibacterial activity against both gram-positive organisms (primarily Staphylococcus aureus, the most common cause of styes) and gram-negative bacteria, with MIC values reduced 3-4 fold compared to single agents 3, 4
Clinical Monitoring
Reassess at 5 days: If no improvement is seen, consider extending treatment to the full 14 days or switching to an alternative antibiotic 1
Discontinue at 7-10 days if complete resolution occurs, as prolonged use beyond clinical cure does not improve outcomes and may increase resistance risk 1
Important Caveats
Do not confuse styes (hordeola) with orbital cellulitis or other deep tissue infections of the eye, which require 7-14 days of systemic antibiotics and cannot be treated with topical therapy alone 5
If the stye progresses to involve deeper structures, develops systemic signs, or fails to respond to topical therapy within 5 days, systemic antibiotics and/or incision and drainage may be necessary 1
Neomycin-polymyxin B combinations are most effective when they contain 1.75-3.50 mg neomycin and 3,000-6,000 units polymyxin B per gram, which is the standard formulation in Neo Poly Bac 4