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

To determine the effect of telmisartan on intraocular pressure (IOP), blood pressure (BP), and ocular perfusion pressure (OPP) in normal and glaucomatous cats. 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. 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. 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. 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.