Concomitant limaprost use and intraocular pressure response to latanoprost in normal-tension glaucoma

Normal-tension glaucoma (NTG) is a progressive optic neuropathy in which intraocular pressure (IOP) reduction is important for limiting disease progression. Latanoprost is commonly used as first-line therapy, but treatment response varies. We investigated whether concomitant oral limaprost use was associated with the IOP response to latanoprost in patients with NTG. We retrospectively reviewed patients with NTG treated between January 2015 and August 2021 at the Veterans Health Service Medical Center. The final matched cohort included 446 patients: 223 patients receiving latanoprost with concomitant limaprost and 223 age- and sex-matched controls receiving latanoprost alone. Three-month IOP was analyzed at the patient level.Multivariable linear regression was performed with 3-month IOP as the outcome, adjusting for baseline IOP, age, sex, nonsteroidal anti-inflammatory drug use, systemic beta-blocker use, diabetes, and hypertension. Baseline IOP was similar between groups. The median IOP reduction at 3 months was 1.0 mm Hg [interquartile range (IQR), −0.5 to 2.5] in the limaprost group and 2.0 mm Hg [IQR, 0.5–3.0] in controls. In the adjusted analysis, concomitant limaprost use was associated with a 0.91-mm Hg higher IOP at 3 months (95% confidence interval, 0.54 to 1.27; P < .001). In a secondary exploratory subgroup of 63 patients who subsequently received add-on dorzolamide/timolol, 35 were in the limaprost group and 28 were controls; no statistically significant between-group difference in IOP reduction was detected. Concomitant limaprost use was associated with a modestly smaller observed IOP reduction after latanoprost treatment in patients with NTG. Because of the retrospective design and the modest magnitude of the association, prospective studies are needed to determine whether a clinically meaningful pharmacologic interaction exists.