24-hour control of intraocular pressure with 2% dorzolamide/0.5% timolol fixed-combination ophthalmic solution in open-angle glaucoma

[Efficacy and safety of the fixed combination of dorzolamide/timolol (Dorzotimol) in primary open-angle glaucoma]

Safe and effective glaucoma treatment remains a critical task in ophthalmology. Newly introduced medications, in addition to mandatory registration trials, are also evaluated in real-world clinical settings.

PURPOSE

This study assesses the efficacy and safety of the fixed combination of dorzolamide/timolol (Dorzotimol) in patients with primary open-angle glaucoma (POAG) in real-world clinical settings.

MATERIAL AND METHODS

The study included 55 patients aged 46 to 75 years with stage I and II POAG. The initial mean intraocular pressure (IOP) was 24.07±1.31 mm Hg. All patients were prescribed the fixed combination of dorzolamide/timolol.

RESULTS

The mean IOP after 1, 3, 6, and 12 weeks of therapy was 19.20±2.46, 18.48±2.04, 17.88±1.88, and 17.62±1.63 mm Hg, respectively. After 12 weeks of therapy, IOP reduction to 18 mm Hg was observed in 63.64% of patients, a reduction of 20% or more from baseline in 81.82% of patients, and a reduction of 30% or more in 14.55% of patients. No serious adverse events were recorded during the observation period.

CONCLUSION

This study confirms the high hypotensive efficacy and safety of the fixed combination of dorzolamide/timolol (Dorzotimol).

Dorzolamide/Timolol Fixed Combination: Learning from the Past and Looking Toward the Future

The key clinical attributes of preserved dorzolamide/timolol fixed combination (DTFC) and the emerging potential of preservative-free (PF) DTFC are reviewed with published evidence and clinical experience. The indications and role of DTFC in current glaucoma management are critically discussed. Preserved DTFC became the first intraocular pressure (IOP)-lowering fixed combination (FC) approved by the US Food and Drug Administration (FDA) and remains one of most commonly used medications worldwide. The pharmacological properties of DTFC reflect those of its two time-tested constituents, i.e., the carbonic anhydrase inhibitor dorzolamide and the non-selective beta-blocker timolol. In regulatory studies DTFC lowers IOP on average by 9 mmHg (32.7%) at peak and by 7.7 mmHg (27%) at trough. In trials DTFC shows equivalence to unfixed concomitant therapy, but in real-life practice it may prove superior owing to enhanced convenience, elimination of the washout effect from the second drop, improved tolerability, and better adherence. PF DTFC became the first PF FC approved, first in unit-dose pipettes, and more recently in a multidose format. Cumulative evidence has confirmed that PF DTFC is at least equivalent in efficacy to preserved DTFC and provides a tangible clinical benefit to patients with glaucoma suffering from ocular surface disease by improving tolerability and adherence. Finally, we identify areas that warrant further investigation with preserved and PF DTFC

Meta-analysis of Timolol on Diurnal and Nighttime Intraocular Pressure and Blood Pressure

Purpose

To evaluate the nighttime intraocular pressure (IOP) and blood pressure (BP) response to timolol treatment in patients with ocular hypertension or primary open-angle glaucoma.

Methods

This was a meta-analysis of previously published studies that must have been randomized, prospective, crossover or parallel, single or double-masked trials. The treatment period must have been ≥2 weeks with ≥19 patients per treatment arm for a crossover, and ≥50 patients for a parallel designed trial. Studies must have included both baseline and treated 24-hour curves.

Results

For the IOP analysis, we included 8 articles with 340 patients. A reduction from baseline was observed for timolol at each time point and for the 24-hour curve (p≤0.009). When 2 studies, in which timolol was used adjunctively were removed, a similar difference was observed as above at each time point and for the 24-hour curve (p≤0.003). In 2 studies, there were small reductions from baseline for the mean diastolic and systolic BPs at most time points and for the 24-hour curve (3.9 and 4.2 mmHg, respectively) with timolol treatment. The ocular perfusion pressure did not show any difference between baseline and timolol treatment at any time point or for the 24-hour curve (p>0.05).

Conclusions

This meta-analysis suggests that topical timolol therapy provides an ocular hypotensive effect over the 24-hour curve, including the nighttime hours, and while small reductions in the systolic and diastolic pressures occur, the ocular perfusion pressure is not altered over 24 hours.

24-h Efficacy of Glaucoma Treatment Options

Current management of glaucoma entails the medical, laser, or surgical reduction of intraocular pressure (IOP) to a predetermined level of target IOP, which is commensurate with either stability or delayed progression of visual loss. In the published literature, the hypothesis is often made that IOP control implies a single IOP measurement over time. Although the follow-up of glaucoma patients with single IOP measurements is quick and convenient, such measurements often do not adequately reflect the untreated IOP characteristics, or indeed the quality of treated IOP control during the 24-h cycle. Since glaucoma is a 24-h disease and the damaging effect of elevated IOP is continuous, it is logical that we should aim to understand the efficacy of all treatment options throughout the 24-h period. This article first reviews the concept and value of diurnal and 24-h IOP monitoring. It then critically evaluates selected available evidence on the 24-h efficacy of medical, laser and surgical therapy options. During the past decade several controlled trials have significantly enhanced our understanding on the 24-h efficacy of all glaucoma therapy options. Nevertheless, more long-term evidence is needed to better evaluate the 24-h efficacy of glaucoma therapy and the precise impact of IOP characteristics on glaucomatous progression and visual prognosis.

Intraocular pressure-lowering effects of commonly used fixed-combination drugs with timolol: a systematic review and meta-analysis

Background

The first goal of medical therapy in glaucoma is to reduce intraocular pressure (IOP), and the fixed-combination medications are needed to achieve sufficiently low target IOP. The aim of this systematic review and meta-analysis is to evaluate IOP-lowering effect of the commonly used fixed-combination drugs containing 0.5% timolol.

Methods

Pertinent publications were identified through systematic searches. Over 85% of the patients had to be diagnosed with primary open-angle glaucoma (POAG) or ocular hypertension (OHT). Forty-one randomized clinical trials were included in the meta-analysis. The main efficacy measures were the absolute and relative values of mean diurnal IOP reduction, and the highest and lowest IOP reductions on the diurnal IOP curve. The pooled 1- to 3-month IOP-lowering effects after a medicine-free washout period was calculated by performing meta-analysis using the random effects model, and relative treatment effects among different fixed combinations were assessed using a mixed-effects meta-regression model.

Results

The relative reductions for mean diurnal IOP were 34.9% for travoprost/timolol, 34.3% for bimatoprost/timolol, 33.9% for latanoprost/timolol, 32.7% for brinzolamide/timolol, 29.9% for dorzolamide/timolol, and 28.1% for brimonidine/timolol. For the highest IOP decrease, relative reductions ranged from 31.3% for dorzolamide/timolol to 35.5% for travoprost/timolol; for the lowest IOP decrease, those varied from 25.9% for dorzolamide/timolol to 33.1% for bimatoprost/timolol. Both latanoprost/timolol and travoprost/timolol were more effective in lowering mean diurnal IOP than brimonidine/timolol (WMD: 5.9 and 7.0) and dorzolamide/timolol (WMD: 3.8 and 3.3).

Conclusions

All six commonly used fixed-combination drugs containing timolol can effectively lower IOP in patients with POAG and OHT, and both latanoprost/timolol and travoprost/timolol might achieve better IOP-lowering effects among the six fixed-combination agents.

Intraocular pressure and ocular hemodynamics in patients with primary open-angle glaucoma treated with the combination of morning dosing of bimatoprost and dorzolamide hydrochloride

AIMS

This prospective, multicenter, single-masked study evaluated the additive effect of dorzolamide hydrochloride 2% on the diurnal intraocular pressure (IOP) curve and retinal and retrobulbar hemodynamics in patients with primary open-angle glaucoma (POAG) treated with morning-dosed bimatoprost 0.03%.

METHODS

Eighty-nine patients (aged, 60.7 ± 11.8 years, range 33-80; 68 women) with POAG received bimatoprost dosed once in the morning for 1 month, after which dorzolamide was added twice daily for 2 months. IOP (Goldmann) and arterial blood pressure (BP) and diurnal ocular perfusion pressures (OPP) were measured every 2 hr for 24 hr. Heidelberg retina flowmetry of the retinal microcirculation was recorded four times daily in 64 patients and colour Doppler imaging of the ophthalmic and central retinal arteries was recorded five times daily in 25 patients. All measurements were taken after the two phases of treatment and compared using anova analysis with Bonferroni adjustment.

RESULTS

Mean baseline IOP was 16.5 ± 3.4 mmHg. Mean diurnal IOP with dorzolamide adjunctive therapy (12.9 ± 2.1 mmHg) was significantly lower compared to mean IOP with bimatoprost monotherapy (13.6 ± 2.2 mmHg) (p = 0.03). Adjunctive dorzolamide therapy significantly decreased vascular resistance in the ophthalmic artery (p = 0.02). Mean diastolic BP and OPP were significantly lower after adjunctive therapy. There were no changes in retinal microcirculation between the two phases of treatment.

CONCLUSIONS

Adjunctive dorzolamide therapy to morning-dosed bimatoprost 0.03% reduced diurnal IOP and vascular resistance in the ophthalmic artery but did not alter retinal circulation in this group of patients with POAG.

Relationship between visual field severity and response to fixed combination dorzolamide/timolol or timolol alone

PURPOSE

To examine the response to intraocular pressure (IOP)-lowering medications as a function of glaucoma severity represented by visual field defects.

METHODS

Post hoc analysis of a multicenter, double-masked, parallel study comparing the 24-h efficacy of the dorzolamide/timolol fixed combination (N = 117) versus timolol alone (N = 115) in patients with open-angle glaucoma or ocular hypertension. Visual field scoring was performed independently by three glaucoma specialists. Two scoring systems were used: the Advanced Glaucoma Intervention Study (AGIS) scoring system and a classical visual field scoring system. Patients were divided into three groups based on their visual field scores. The changes from baseline daytime and nighttime mean IOP, and 24-h IOP fluctuation after 8 weeks of treatment by baseline glaucoma severity, were compared across treatments using a simple linear regression analysis.

RESULTS

Most (approximately 73%) patients had no visual field damage at baseline. With either dorzolamide/timolol or timolol alone, there was no significant difference in IOP response from baseline over 24 h based on the level of visual field damage, as measured by either the AGIS or the classic visual field scoring systems. The Pearson's rho correlations between the baseline AGIS score and the change in daytime IOP, nighttime IOP, and 24-h IOP range were 0.0024 (P = 0.97), -0.086 (P = 0.21), and 0.076 (P = 0.26), respectively. Correlations by classic score were 0.024 (P = 0.72), -0.074 (P = 0.28), and 0.061 (P = 0.37), respectively.

CONCLUSIONS

This analysis showed no significant relation between the severity of baseline visual field defects and the ocular hypotensive efficacy of the dorzolamide/timolol fixed combination and timolol alone.