Apraclonidine. A one-week dose-response study
H. D. Jampel, A. L. Robin, H. A. Quigley and I. P. Pollack
Glaucoma Services, Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, MD.
We performed a double-masked, cross-over, dose-response study of
apraclonidine hydrochloride (formerly known as ALO 2145) in 20 patients
with elevated intraocular pressure (IOP). We administered three
concentrations of apraclonidine (0.125%, 0.25%, 0.5%) and vehicle alone
bilaterally every 12 hours for one week. Patients were examined 2, 5, and 8
hours after the initial dose, and then on day 2 and day 8. We studied IOP,
pupillary diameter, interpalpebral fissure width, blood pressure, and
pulse. There was a two-week washout period after each one-week session. All
concentrations of apraclonidine significantly lowered IOP. The 0.5% and
0.25% concentrations had equal maximal effects, lowering IOP in each
patient by an average of 27% relative to vehicle alone. This corresponded
to a mean decrease in IOP of 8.7 mm Hg, from a baseline of 24.9 mm Hg to
16.2 mm Hg. The 0.5% and 0.25% concentrations were significantly more
effective than the 0.125% concentration at two and eight hours. Mean
interpalpebral fissure width increased in a dose-dependent fashion; the
pupillary effect was minimal. Blood pressure and pulse were unchanged.
Thirty percent of subjects reported transient dry nose or dry mouth. These
symptoms may be dose-dependent.
