The efficacy of apraclonidine as an adjunct to timolol therapy. Apraclonidine Adjunctive Therapy Study Group [published errata appear in Arch Ophthalmol 1995 Sep;113(9):1112 and 1995 Nov;113(11):1465]
W. C. Stewart, R. Ritch, D. H. Shin, R. P. Lehmann, C. E. Shrader and E. M. van Buskirk
Medical University of South Carolina, Charleston.
OBJECTIVE: To compare the intraocular pressure (IOP) lowering efficacy of
0.5% and 1.0% apraclonidine hydrochloride when used adjunctively with 0.5%
timolol maleate in 129 patients. DESIGN: A multicenter, randomized,
double-masked clinical trial. Adult patients of either sex diagnosed as
having either open-angle glaucoma or ocular hypertension were enrolled in
the study. Patients using only 0.5% timolol maleate twice daily for at
least 4 weeks and who had 8 AM IOPs of at least 22 mm Hg and no greater
than 30 mm Hg 12 hours after dosing were eligible for the study. After 8 AM
baseline IOPs were obtained while patients were taking timolol only, they
were then randomized to receive either 0.5% or 1.0% apraclonidine twice
daily in addition to their timolol. Intraocular pressures were measured at
8 AM (before morning dosing) and at 11 AM (3 hours after dosing) on days 14
and 90 and at 8 AM only on day 45. RESULTS: Both concentrations of
apraclonidine produced significant IOP reductions from baseline at all
visits (P < .001). At 8 AM, after the nighttime dose, the additional
mean IOP reduction from the timolol baseline ranged from 2.5 to 3.3 mm Hg
(10.3% to 13.6% reduction, respectively). At 11 AM, 3 hours after the
morning dose, the additional IOP reduction from the timolol baseline ranged
from 4.7 to 5.2 mm Hg (20.0% to 21.7%, respectively). No difference in IOP
reduction was observed between the 0.5% and 1.0% apraclonidine
concentrations and no loss of IOP efficacy was observed for either
concentration for the duration of the study. Sensitivity to 0.5% and 1.0%
apraclonidine was observed in nine (13.8%) and 13 (20.3%) patients,
respectively. Overall, therapy was discontinued owing to ocular or
nonocular side effects with 0.5% and 1.0% apraclonidine in 14 (21.5%) and
16 (25%) patients, respectively. CONCLUSIONS: We believe that 0.5%
apraclonidine is equally effective as 1.0% apraclonidine when used twice
daily as the first adjunctive drug to timolol. The drug effect is
maintained for at least 90 days.
