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March 1995

The Efficacy of Apraclonidine as an Adjunct to Timolol Therapy

Author Affiliations

From the Medical University of South Carolina, Charleston (Dr Stewart); New York (NY) Eye and Ear Infirmary (Dr Ritch); Wayne State University, Detroit, Mich (Dr Shin); Lehmann Eye Center, Nacogdoches, Tex (Dr Lehmann); Eye Clinic of Wichita (Kan) (Dr Shrader); and Devers Eye Institute, Portland, Ore (Dr van Buskirk). Participants of the Apraclonidine Adjunctive Therapy Study Group are listed on page 292. The authors have no proprietary interest in either Alcon Laboratories Inc and apraclonidine or Merck & Co Inc and timolol.

Arch Ophthalmol. 1995;113(3):287-292. doi:10.1001/archopht.1995.01100030041019

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.

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