Intraocular pressure lowering effect of dorzolamide/timolol fixed combination in patients with glaucoma who were unresponsive to prostaglandin analogs/prostamides^*

ABSTRACT

Objective: To evaluate the intraocular pressure lowering effect of the dorzolamide/timolol fixed combination (DTFC) in non-responder glaucoma patients to prostaglandin analogs/prostamides (prostas).

Patients and methods: All glaucoma patients treated with DTFC, between June 2003 and December 2005, who were unresponsive to prostaglandin analogs/prostamides, were identified through a retrospective medical records review. A non-responder was defined as an intraocular pressure (IOP) lowering effect less than 15% compared with baseline measurement. Two 12‑hour IOP diurnal curves, measured between 8:00 a.m. and 8:00 p.m. (8:00 a.m., 10:00 a.m., 12:00 noon, 2:00 p.m., 4:00 p.m., 6:00 p.m. and 8:00 p.m.), were obtained retrospectively from the records of 31 patients, the first while on prostaglandin analogs/prostamides (baseline IOP) and the second while receiving DTFC (DTFC IOP). The study outcomes were the change in mean diurnal IOP and the reduction in IOP fluctuation as a result of receiving DTFC in patients unresponsive to prostas. The IOP was evaluated by intragroup comparisons with a two-tailed paired Student's t‑test. A chi-square test was adopted for analysis of categorical variables.

Results: 31 patients were included in this retrospective study. DTFC significantly reduced IOP in the patients overall, from 25.4 (3.5) to 20.2 (1.0) mmHg, p < 0.0001. The majority of patients were diagnosed with pseudoexfoliative glaucoma (PEX) (58%; 18/31). DTFC reduced the mean IOP fluctuations over 12 hours (highest minus lowest IOP reading within the 12‑hours pressure curve) from 8.6 (3.2) to 4.3 (1.4) mmHg, p < 0.0001. The most common adverse events were ocular burning (16%) and taste perversion (13%). There were no serious treatment-related adverse events.

Conclusion: DTFC significantly reduced the IOP in patients with glaucoma who did not respond to prostaglandin analogs/prostamides. Further research is needed to confirm these results.

Key words: :

• Dorzolamide/timolol fixed combination
• Non-responders
• Primary open-angle glaucoma
• Prostaglandin analogs
• Prostamides
• Pseudoexfoliative glaucoma