Effects of the combination of bimatoprost and latanoprost on intraocular pressure in primary open angle glaucoma: a randomised clinical trial

AIMS: To evaluate the effect of the combination of bimatoprost and latanoprost on intraocular pressure (IOP) in primary open angle glaucoma (POAG). METHODS: An open label randomised clinical trial was conducted, which included 18 glaucomatous patients (36 eyes). In the first 4 weeks, latanoprost 0.005% was prescribed for both eyes of the patients and any other antiglaucoma medication was discontinued. In the next 4 weeks (phase 1), bimatoprost 0.03% was combined with latanoprost in one randomly assigned eye (case eye) of each patient. In the next 4 weeks (phase 2), bimatoprost was discontinued in the case eyes, while bimatoprost was substituted for latanoprost in the fellow eye (control eye). The IOP was measured at the end of the first 4 weeks (baseline measurement) and weekly during phases 1 and 2. RESULTS: In the case eyes, the mean IOP increased along the first phase (1.8 mm Hg; p = 0.006) when compared to baseline measurements. The IOP returned to previous values after discontinuation of bimatoprost in phase 2. In the control eyes, the mean IOP did not change throughout the study. CONCLUSION: The combination of bimatoprost and latanoprost in POAG increases the IOP and should not be considered as a therapeutic option.