What is the dosing for Polytrim (polymyxin B sulfate and trimethoprim) eye drops?

From the Guidelines

Polytrim eye drops should be dosed at least 3 to 4 times a day to avoid subtherapeutic levels and reduce the risk of antibiotic resistance. When treating bacterial keratitis, especially in the presence of virulent or indolent organisms or in immunocompromised patients, it is crucial to maintain an adequate dosing frequency 1.

Key Considerations

• The dosing frequency of Polytrim eye drops is critical in ensuring the effectiveness of the treatment and preventing the development of antibiotic resistance.
• A dose of 1-2 drops in the affected eye(s) every 4 hours is a common recommendation for bacterial conjunctivitis or corneal infections.
• Treatment should typically continue for 7-10 days, even if symptoms improve earlier, to ensure complete eradication of the infection.

Administration Guidelines

• Before applying Polytrim eye drops, wash your hands thoroughly to prevent contamination.
• Tilt your head back, pull down the lower eyelid to form a pocket, and instill the drops without touching the dropper tip to any surface.
• After application, close your eyes gently for 1-2 minutes to allow the medication to be absorbed.
• If using other eye medications, wait at least 5 minutes between applications to avoid potential interactions.

Mechanism of Action and Side Effects

• Polytrim contains trimethoprim and polymyxin B, which work together to kill bacteria by disrupting protein synthesis and cell membranes.
• Common side effects may include temporary burning or stinging, blurred vision, and eye irritation.
• Contact your doctor if you experience severe irritation, worsening symptoms, or if your condition doesn't improve after 2-3 days of treatment, as this may indicate a need to adjust the treatment regimen or address potential complications 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Adults: In mild to moderate infections, instill one drop in the affected eye(s) every three hours (maximum of 6 doses per day) for a period of 7 to 10 days. Pediatric Use: Clinical studies have shown Trimethoprim and Polymyxin B Sulfate Ophthalmic Solution to be safe and effective for use in pediatric patients over two months of age. The dosage regimen is the same as for adults. The recommended dosing for Polytrim eye drops is:

• 1 drop in the affected eye(s)
• Every 3 hours
• Maximum of 6 doses per day
• For a period of 7 to 10 days 2

From the Research

Polytrim Eye Drop Dosing

• The dosing of Polytrim eye drops, which contain polymyxin B sulfate and trimethoprim, can vary depending on the specific condition being treated and the patient population 3, 4, 5, 6.
• In a study comparing the efficacy of polymyxin B sulfate/trimethoprim and moxifloxacin for the treatment of bacterial conjunctivitis, patients were randomly assigned to receive either 1 drop of polymyxin/trimethoprim four times daily for 7 days or 1 drop of 0.5% moxifloxacin three times daily for 7 days 3.
• Another study evaluated the subjective response to treatment with trimethoprim-polymyxin B of children with presumed acute bacterial conjunctivitis, and found that 95% of infected eyes were cured or improved within 7 days 4.
• A single-blinded randomized clinical trial compared polymyxin B-trimethoprim and moxifloxacin for the treatment of acute conjunctivitis in children, and found that both treatments were effective, with no significant difference in clinical efficacy between the two groups 5.
• A multicentre trial compared the efficacy of trimethoprim-polymyxin B ophthalmic solution with neomycin-polymyxin B-gramicidin and chloramphenicol ophthalmic solutions for the treatment of presumptive bacterial conjunctivitis, and found that trimethoprim-polymyxin B was significantly better than chloramphenicol in reducing signs and symptoms 6.

Key Findings

• Polymyxin B sulfate/trimethoprim is effective for the treatment of bacterial conjunctivitis, with a clinical response rate that does not differ from moxifloxacin 3, 5.
• Trimethoprim-polymyxin B ophthalmic solution is effective and well-tolerated for the treatment of acute bacterial conjunctivitis in children 4.
• The combination of polymyxin B/trimethoprim and rifampin has been shown to be effective against Pseudomonas aeruginosa clinical isolates, and may represent a promising therapeutic for P. aeruginosa keratitis 7.