What is the recommended dose of Polytrim (polymyxin B sulfate and trimethoprim) for conjunctivitis in a 6-month-old infant?

Polytrim Dosing for Conjunctivitis in a 6-Month-Old

For a 6-month-old infant with bacterial conjunctivitis, administer Polytrim (trimethoprim-polymyxin B) as one drop in the affected eye(s) every 3 hours while awake (maximum 6 doses per day) for 7 to 10 days. 1

FDA-Approved Dosing

• Polytrim is safe and effective for infants over 2 months of age, with the same dosing regimen as adults 1
• The standard regimen is one drop every 3 hours (maximum 6 doses daily) for 7-10 days 1
• This dosing applies to both mild and moderate bacterial conjunctivitis 1

Clinical Efficacy in Pediatric Populations

• Trimethoprim-polymyxin B demonstrates excellent efficacy in children with acute bacterial conjunctivitis, with 95% of infected eyes cured or improved within 7 days 2
• The combination provides broad-spectrum coverage against the most common pediatric pathogens: Haemophilus influenzae and Streptococcus pneumoniae 2
• Physicians rated overall efficacy as excellent or good in 96% of pediatric cases 2

Important Clinical Considerations

When to expect improvement:

• Most children show clinical improvement by 3-5 days of treatment 3
• If no improvement occurs after 3-4 days, consider culture and sensitivity testing 4
• Bacterial eradication typically occurs in 71% of cases by days 3-5 3

Safety profile:

• Adverse events are rare, transient, and mild-to-moderate in intensity 2
• Patients report being very comfortable or moderately comfortable in 89% of cases 2

Critical Pitfalls to Avoid

Rule out serious infections first:

• Any purulent conjunctivitis in an infant under 1 year requires immediate evaluation to exclude gonococcal or chlamydial infection, which require systemic antibiotics 5
• Gonococcal conjunctivitis can cause corneal perforation within 24-48 hours and requires immediate systemic treatment 5
• Always examine the cornea with fluorescein staining to detect early corneal involvement 5

When Polytrim is NOT appropriate:

• Gonococcal conjunctivitis requires ceftriaxone 25-50 mg/kg IV/IM (single dose, not exceeding 250 mg) plus systemic azithromycin 6
• Chlamydial conjunctivitis requires erythromycin base 50 mg/kg/day orally divided into 4 doses for 14 days 6
• Severe purulent discharge that rapidly reaccumulates after cleaning warrants immediate referral 7

Infection Control

• The infant remains infectious until 24-48 hours after starting appropriate antibiotic treatment 7
• Should not attend daycare until completing 24 hours of antibiotic therapy 7
• Careful hand hygiene and separate towels are essential to prevent spread 7