Effects of Telmisartan on Intraocular Pressure, Blood Pressure, and Ocular Perfusion Pressure in Normal and Glaucomatous Cats.

Purpose: To determine the effect of telmisartan on intraocular pressure (IOP), blood pressure (BP), and ocular perfusion pressure (OPP) in normal and glaucomatous cats. Methods: A four-week study was conducted in six normal adult cats, followed by a longer six-month study performed in 37 cats with spontaneous glaucoma and 11 age-matched normal cats. Telmisartan (1 mg/kg/day) or placebo-vehicle were administered orally once daily. IOP was measured by rebound tonometry. BP readings were obtained by oscillometric method. OPP was calculated as mean arterial pressure (MAP) - IOP. IOP and BP were obtained three times a week for the first study and weekly for the second study. Results: Baseline IOP was significantly higher, and OPP was significantly lower in glaucomatous cats than in normal cats (P < 0.0001). These differences between glaucomatous and normal cats persisted throughout the study, regardless of treatment (P < 0.001). No significant differences in IOP, BP, or OPP were detected between any study phases in the first, normal feline cohort or between telmisartan- and placebo-treated glaucomatous cats at any timepoint in the second study. Conclusions: Oral telmisartan was well tolerated and did not have a detrimental effect on BP or OPP in cats but did not lower IOP or improve OPP in cats with glaucoma. Translational Relevance: While showing telmisartan could not be used as a sole therapy for IOP lowering, our data affirmed a lack of detrimental effects of telmisartan on BP and OPP in a translationally-relevant, spontaneous, large animal glaucoma model.