Intraocular pressure-lowering effect of 0.005% latanoprost with two different dosing regimens.

PURPOSE: To compare the intraocular pressure (IOP)-lowering effect of 0.005% latanoprost used once every other day versus once daily in patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT).

METHODS

Forty eyes of 20 patients with bilateral OHT or early POAG were enrolled in this prospective, randomized, crossover study. After a washout period of 1-4 weeks, each patient started latanoprost once daily in 1 randomly assigned eye and once every other day in the other eye. After 1 month, eyes were crossed over to the opposite dosing regimen for another month. IOP was measured at 9 am, 4 pm, and 9 pm, both at baseline and on 2 consecutive days, at the end of the first and second months. The main outcome measure was IOP reduction on the second day at the end of the first and second months.

RESULTS

Mean±standard deviation (SD) baseline IOPs (mmHg) in the right and left eye were 25.6±2.6 and 25.5±2.7 (P=0.8), respectively. Mean±SD diurnal IOPs decreased (mmHg) by 8.6±2.5 in the once-daily group versus 7.3±2.3 in the every-other-day group (P<0.001) at the end of the first month and 8.4±2.5 versus 7.7±2.5 at the end of the second month (both on day 2) (P=0.01).

CONCLUSIONS

Once every-other-day administration of latanoprost significantly reduced the IOP although the IOP reduction was less pronounced 36-48 h after drug application.