Study: 12-hour dosing of carbonic anhydrase inhibitor controls IOP after phaco

Application of a single drop of brinzolamide 1% can sufficiently control IOP within the first 4 to 6 hours after uneventful phacoemulsification, a prospective study found. However, 12-hour dosing may be necessary to control IOP through 1 day postop.

Erkin Kir, MD, and colleagues compared the IOP-lowering efficacy of applying Azopt (brinzolamide 1%, Alcon) in one of two dosing regimens with no hypotensive medication among 60 eyes of 60 patients with similar preop IOPs who underwent uneventful clear corneal phaco. Specifically 20 eyes received a single drop of brinzolamide immediately after surgery, 20 eyes received one drop in 12-hour intervals immediately after speculum removal and 20 control eyes received no medication.

At 4 to 6 hours postop, both the single drop and 12-hour dosing groups had significantly lower IOPs than the control group; this trend persisted through 24 hours postop in the 12-hour dosing group (P = .001), but not in the single drop group.

In the control group, one eye experienced a postoperative IOP elevation greater than 30 mm Hg between 4 and 6 hours postop.

The investigators reported IOP increases of greater than 5 mm Hg in four eyes in both dosing groups, as well as 14 eyes in the control group, at 4 to 6 hours postop.

The study is published in the October issue of Canadian Journal of Ophthalmology.