Cardiovascular and intraocular pressure effects and plasma concentrations of apraclonidine
A. L. Coleman, A. L. Robin, I. P. Pollack, M. T. Rudikoff, C. Enger and P. R. Mayer
Glaucoma Service, Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Md.
We performed a double-masked, crossover study comparing the cardiovascular
and intraocular pressure effects of 0.5% and 0.25% topical apraclonidine
hydrochloride and 0.5% timolol maleate in 20 healthy female volunteers. The
contralateral effects of unilateral apraclonidine and the plasma
concentrations of apraclonidine were also assessed. All measurements were
done 2, 5, and 8 hours after drop instillation. A 15-minute treadmill test
was performed after the 2-hour measurements. All three active medications
lowered intraocular pressure comparably. There was no significant
contralateral intraocular pressure effect seen with apraclonidine. The
apraclonidine plasma concentrations were variable and unrelated to the
amount of intraocular pressure lowering and cardiovascular parameters
measured. Apraclonidine did not affect blood pressure or heart rate any
differently than placebo. Timolol, however, blunted exercise-induced
tachycardia. There were no significant differences in pupillary diameters
or interpalpebral fissure widths among treatment groups.
