The cardiovascular, pulmonary, and ocular hypotensive effects of 0.2% brimonidine
J. R. Nordlund, L. R. Pasquale, A. L. Robin, M. T. Rudikoff, J. Ordman, K. S. Chen and J. Walt
Wilmer Ophthalmological Institute, Baltimore, Md.
OBJECTIVE: To compare the cardiovascular, pulmonary, and ocular hypotensive
effects of 0.2% brimonidine tartrate with those of 0.5% timolol maleate,
0.25% betaxolol suspension, and brimonidine vehicle. DESIGN AND PATIENTS: A
single-center, double-masked, randomized, crossover study of 24 young,
healthy men. INTERVENTIONS: Baseline heart rate, blood pressure,
respiratory rate, and intraocular pressure were recorded at hour 0. At hour
2, heart rate, blood pressure, respiratory rate, and forced expiratory
volume in 1 second were measured and a 15-minute treadmill test performed.
Hour 0 measurements were repeated at hour 4. On four subsequent visits, we
instilled one drop of a study medication into each eye after the baseline
measurements at hour 0. RESULTS: Timolol reduced resting (-5.3 to -6.5
beats/min, P < or = .004) and exercise-induced heart rate (-4.3 to -13.6
beats/min; P < or = .022) compared with brimonidine, betaxolol
suspension, and brimonidine vehicle. At hour 4, brimonidine reduced resting
systolic blood pressure compared with all other study medications (-5.2 to
-7.3 mm Hg; P < or = .024). Timolol reduced systolic blood pressure
during exercise and brimonidine reduced systolic blood pressure during
recovery more than betaxolol suspension and brimonidine vehicle (-5.1 to
-7.7 mm Hg; P < or = .033; and -5.4 to -6.0 mm Hg; P < or = .002,
respectively). Mean respiratory rate and forced expiratory volume in 1
second were not significantly altered by any study medication. At hour 4,
brimonidine lowered intraocular pressure as well as timolol and better than
betaxolol suspension (-1.9 mm Hg; P < .001) or brimonidine vehicle (-1.8
mm Hg; P < .001). CONCLUSIONS: The cardiopulmonary effects of 0.2%
brimonidine were limited to a slight reduction in systolic blood pressure
during recovery from exercise and at 4 hours after instillation. The ocular
hypotensive effect of brimonidine was comparable to that of timolol and
greater than that of betaxolol suspension in this patient population.
