Two-year safety study of dorzolamide as monotherapy and with timolol and pilocarpine. Dorzolamide Safety Study Group.

PURPOSE: To evaluate the safety of open-label 2.0% dorzolamide as monotherapy and when used with timolol and/or pilocarpine for as long as 2 years. METHODS: The safety of dorzolamide was evaluated in patients with open-angle glaucoma or ocular hypertension over a 2-year period. The incidence of the most common drug-related adverse experiences in the first year was compared with that in the second year using McNemar's test. The ocular hypotensive effect of dorzolamide as monotherapy and with adjunctive therapy was assessed using percent change in intraocular pressure (IOP) from baseline. RESULTS: Of the 304 patients enrolled, 164 (53.9%) continued to receive dorzolamide as monotherapy for 2 years and 140 (46.1%) required add-on therapy. Add-on therapy was initiated by month 6 in 112 of these 140 patients (80%). Of the 304 patients, 202 (66.4%) completed 2 years of therapy. Of the patients who received dorzolamide as monotherapy, drug-related adverse events occurred more frequently during the first year (29.7%) than the second year (13.8%), and the most common ocular drug-related adverse events included conjunctivitis, burning/stinging eye, follicular conjunctivitis, and eyelid edema. After 2 years of therapy, the mean percent decrease in peak IOP was 22.8% for patients receiving dorzolamide monotherapy and 31.2% to 36.0% for patients receiving add-on therapy. CONCLUSION: Dorzolamide was generally well tolerated for up to 2 years as monotherapy and when used with timolol and/or pilocarpine. Drug-related adverse events were less frequent during the second year of monotherapy than during the first year. Most patients who required add-on therapy did so within the first 6 months of initiating dorzolamide therapy.