Moxifloxacin has higher aqueous concentrations when given hours before cataract surgery

Administering topical moxifloxacin 2 hours before cataract surgery can achieve significantly higher aqueous concentrations than initiating dosing 1 day before surgery, a prospective, randomized triple-masked study found. However, both dosing regimens produced considerably higher aqueous concentrations than the known minimum inhibitory concentration for Staphylococcus epidermidis.

Abhay R. Vasavada, MS, FRCS, and colleagues at Iladevi Cataract & IOL Research Centre in Ahmedabad, India, randomly assigned 172 patients undergoing cataract surgery to receive one of two dosing regimens of preoperative Vigamox (moxifloxacin 0.5%, Alcon) and evaluated subsequent aqueous concentrations. Specifically, 86 patients in group one received moxifloxacin four times 1 day before surgery, as well as one drop 2 hours before surgery, for a total of five drops. Eighty-six patients in group two received one drop of the drug 2 hours before surgery and in 15-minute intervals over 1 hour, for a total of five drops.

Aqueous samples were collected for 156 of these patients within 2 hours of the first dose instillation on the day of surgery.

The average duration between the first instillation on the day of surgery to aqueous collection was 119 minutes in group one and 117 minutes in group two, the authors noted.

The investigators found that aqueous humor concentration of moxifloxacin averaged 1.58 µg/mL in group one and 2.05 µg/mL in group two, according to the study, published in the August issue of Journal of Cataract & Refractive Surgery.