Dorzolamide May Be Effective, Well Tolerated for Pediatric Glaucoma

Laurie Barclay, MD

September 13, 2005

Sept. 13, 2005 -- Dorzolamide is efficacious and well tolerated for glaucoma treatment in children younger than six years, according to the results of a randomized trial published in the September issue of the Archives of Ophthalmology.

"The topical carbonic anhydrase inhibitor dorzolamide hydrochloride (Trusopt; Merck & Co, Inc, Whitehouse Station, NJ) has been studied in pediatric glaucoma patients and has had good tolerability and has lowered intraocular pressure (IOP), although not as much as oral acetazolamide," write Elyssa Z. Ott, BS, from Merck Research Laboratories in West Point, Pennsylvania, and colleagues from the Pediatric Dorzolamide Study Group. "However, the information provided by these reports is less than comprehensive."

In this three-month, double-masked, multicenter trial, patients were randomized to receive 2% dorzolamide three times daily or timolol maleate gel-forming solution (0.25% for patients younger than two years and 0.5% for patients at least two but younger than six years of age) once daily plus placebo twice daily. If monotherapy was insufficient to control IOP, younger patients were also given dorzolamide three times daily and 0.25% timolol gel-forming solution once daily, and older patients were given a fixed combination of 2% dorzolamide and 0.5% timolol twice daily. The primary safety outcome was the proportion of patients who discontinued therapy because of a drug-related adverse event, and a secondary measure was IOP reduction.

Of 56 younger patients randomized to dorzolamide, one (1.8%) discontinued concomitant therapy because of bradycardia. Two (3.0%) of 66 older patients discontinued dorzolamide because of ocular adverse events. The most commonly reported ocular adverse events were discharge and ocular hyperemia in the younger cohort, and ocular hyperemia and burning or stinging in the older cohort.

With dorzolamide, the mean change in IOP from baseline to week 12 was -7.3 mm Hg (-20.6%) in the younger cohort and -7.1 mm Hg (-23.3%) in the older cohort ( P < .001 for both).

"Dorzolamide was generally well tolerated and demonstrated efficacy for up to three months in patients younger than six years," the authors write. "In addition, 2% dorzolamide monotherapy seemed to be comparable in safety in this study population to that reported in previous adult studies and comparable in efficacy to that reported in the published pediatric literature."

Merck & Co., Inc. supported this study, employs four of the authors, and provided research grants to two other authors.

Arch Ophthalmol. 2005;123:1177-1186

Reviewed by Gary D. Vogin, MD


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