Long-term Glaucoma Treatment with MK-507, Dorzolamide, a Topical Carbonic Anhydrase Inhibitor.
OBJECTIVE
The purpose of this study was to examine the long-term efficacy and safety of dorzolamide (a topical carbonic anhydrase inhibitor, previously known as MK-507) as an ocular hypotensive agent.


METHODS
This open-labeled, multicenter, 52-week trial enrolled patients with primary open-angle glaucoma or ocular hypertension. One percent dorzolamide hydrochloride was instilled in both eyes of each patient every 8 h. On the 1st day of the study, intraocular pressure (IOP) was measured with a Gold-mann applanation tonometer at 8:30 and 10:30 a.m. Patients were examined at least every 4 weeks. During each clinic visit, dorzolamide was given at 12:30 a.m., and IOP was determined 8 h later. After IOP measurements, dorzolamide was administered again. Further IOP readings were taken 2 h later at 10:30 a.m. Patients were monitored closely by testing for visual acuity, anterior segment, and by continuously evaluating symptoms.


RESULTS
Ninety-eight patients entered the study and 81 patients (82.7%) completed the study according to the protocol. Three patients had to be withdrawn because of untoward reactions; two experienced ocular discomfort and one developed palpitation. Four patients required additional ocular hypotensive medication for further IOP reduction. One patient was excluded from the analysis because the patient was younger than age 20, which violated the protocol. Dorzolamide significantly reduced IOP by 12.9-17.5% at 8 h after administration and by 16.7-24.1% at 2 h after administration. The IOP decrease was consistent throughout the 52-week trial without waning or potentiation. Our results indicate that dorzolamide may be a safe and effective ocular hypotensive agent.