Brimonidine-purite 0.1% versus brimonidine-purite 0.15% twice daily in glaucoma or ocular hypertension: a 12-month randomized trial

Effects of a Single Dose of Topical Brimonidine 0.15% on Anterior Segment Morphology, Pupil Characteristics, and Choroidal Thickness in Healthy Subjects

PURPOSE

To investigate the effects of a single dose of brimonidine 0.15% on anterior segment morphology, pupil characteristics, and choroidal blood flow in treated and untreated eyes of healthy subjects and to compare the results obtained with those in another healthy volunteer group.

METHODS

Participants were classified as study and control groups. The eyes in the study group were randomized. Only one eye received one drop of brimonidine (treated eyes), and the contralateral eye received single dose of sodium hyaluronate (untreated eyes). In addition, only right eyes of control subjects, who had single dose of sodium hyaluronate to both eyes, were analyzed (control eyes). Anterior segment parameters including central corneal thickness (CCT), aqueous depth, anterior chamber volume, iridocorneal angle (ICA), horizontal anterior chamber diameter, and pupil measurements including scotopic, mesopic, photopic, and dynamic pupil diameters (PDs) were performed with Sirius Scheimpflug camera. Choroidal thickness (CT) measurements were taken with optical coherence tomography. These measurements were taken at baseline and repeated 1 hour after the dosing.

RESULTS

Only the treated eyes had significantly thicker CCT and wider ICA values after instillation of brimonidine. Static and dynamic PD values of treated eyes and even untreated eyes significantly decreased after brimonidine. However, brimonidine has no significant effect on CT measurements.

CONCLUSION

A single dose of brimonidine causes thickening in CCT and widening in ICA values in treated eyes. In addition, it has significant effect to decrease the scotopic, mesopic, photopic, and dynamic PD values in treated and even contralateral eyes while has no effect on choroidal blood flow.

Effects of Brimonidine and Timolol on the Progression of Visual Field Defects in Open-angle Glaucoma: A Single-center Randomized Trial

PRéCIS:: Instillation of brimonidine or timolol slowed visual field deterioration in patients with open-angle glaucoma; both brimonidine and timolol might improve the mean deviation (MD) slopes.

PURPOSE

The purpose of this study was to investigate and compare the effects of 0.1% brimonidine and 0.5% timolol on the progressing visual field defects in open-angle glaucoma.

PATIENTS AND METHODS

We evaluated 1 eye each of 68 glaucoma patients who were treated with at least 1 prostaglandin analog. Their baseline MD slopes were < -0.5 dB/y based on at least 5 Humphrey field analyzer measurements within 3 years. Eligible eyes were randomly assigned to brimonidine or timolol treatment groups and treatments were administered without the wash-out period. Clinical examinations were performed every 4 months for 2 years. We designated the MD slope as the primary endpoint.

RESULTS

Ultimately, 56 eyes (brimonidine:timolol=26:30) were included in the present study (mean age=65.2 y). Dropout rates of brimonidine and timolol treatment groups were 27.8% and 6.3%, respectively. There were no significant differences in baseline intraocular pressure or MD slopes between brimonidine and timolol groups (12.7 and 12.9 mm Hg, P=0.77, and -1.22 and -1.08 dB/y, P=0.43, respectively). Intraocular pressure decreased significantly in the brimonidine group at 4, 8, 12, and 16 months, and in the timolol group at 4 months, without significant differences between the drugs (P=0.20). MD slopes significantly improved in both groups (brimonidine: -0.38 dB/y, P<0.001; timolol: -0.52 dB/y, P=0.04). Furthermore, there was no significant difference between groups in the primary endpoint (P=0.59).

CONCLUSION

Brimonidine and timolol treatments improved MD slopes in open-angle glaucoma.

Meta-analysis of α2-adrenergic agonists versus carbonic anhydrase inhibitors as adjunctive therapy

OBJECTIVE

To evaluate the efficacy of α2-adrenergic agonist (AA) brimonidine and topical carbonic anhydrase inhibitors (CAIs) dorzolamide and brinzolamide in reducing intraocular pressure (IOP) when used as adjunctive therapy to β-blockers (BBs) or prostaglandin analogs (PGAs).

RESEARCH DESIGN AND METHODS

Pertinent publications were identified through systematic searches of PubMed, EMBASE, and the Cochrane Controlled Trials Register. Randomized controlled trials comparing AA with CAIs in patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT) who had inadequate IOP control with monotherapy of a BB or PGA. The weighted mean differences (WMD) of IOP-lowering efficacy were calculated by performing meta-analysis.

MAIN OUTCOME MEASURES

The main efficacy measures were the reduction from baseline to end of treatment in IOP at peak, trough, and diurnal curve.

RESULTS

Eleven published randomized clinical trials involving 1493 patients were included in the meta-analysis. As adjunctive therapy, the IOP reduction was greater in the brimonidine group than in the CAI group at peak (WMD: 0.99 mmHg [95% confidence interval, 0.45 to 1.53]) and diurnal curve (WMD: 0.62 mmHg [0.07 to 1.18]). As adjunctive therapy to BBs, brimonidine was more effective than CAIs in reducing IOP at peak (WMD: 0.85 mmHg [0.42 to 1.29]) and trough (WMD: 0.47 mmHg [0.12 to 0.83]). As adjunctive therapy to PGAs, brimonidine resulted greater reduction in peak IOP than CAIs (WMD: 1.04 mmHg [0.08 to 2.00]).

CONCLUSIONS

Brimonidine provides greater IOP-lowering efficacy than topical carbonic anhydrase inhibitors as adjunctive therapy to BBs or PGAs.

Update on the role of alpha-agonists in glaucoma management

Glaucoma is the second most common cause of world blindness (following cataract) with estimated cases reaching 79.6 million by 2020. Although the etiology of glaucoma is multi-factorial, intraocular pressure (IOP) is the only modifiable factor in glaucoma management proven to alter the natural course of the disease. Among various classes of IOP-lowering medications currently available, alpha-adrenergic receptor agonists are used either as monotherapy, as second-line therapy, or in fixed combination with beta-blockers. Non-selective adrenergic agonists such as epinephrine and dipivefrin are infrequently used today for the treatment of glaucoma or ocular hypertension, and have been replaced by the alpha-2-selective agonists. The use of apraclonidine for IOP reduction in glaucoma or OHT is limited due to a high rate of follicular conjunctivitis. The alpha-2-selective agonist in use today is brimonidine. The brimonidine-purite formulations are preferred to brimonidine-benzalkonium chloride (BAC) formulations due better tolerability while maintaining similar efficacy. Brimonidine is also effective when used in combination with a beta-blocker. Using brimonidine-timolol fixed combination (BTFC) as first-line therapy has an added potential for neuroprotection. This would be a valuable strategy for glaucoma treatment, for patients who are intolerant of prostaglandin analogs, or for patients where prostaglandin analogues are contraindicated as first-line therapy, such as in patients with inflammatory glaucoma.

Safety and tolerability of brimonidine purite 0.1% and brimonidine purite 0.15%: a meta-analysis of two phase 3 studies

OBJECTIVE

To compare the safety and tolerability of two formulations of brimonidine ophthalmic solution, brimonidine Purite (P) 0.1% and brimonidine P 0.15%, for reducing intraocular pressure in patients with glaucoma or ocular hypertension (OHT).

STUDY DESIGN AND METHODS

Meta-analysis of safety and tolerability results from two previously reported prospective, randomized, 12-month, double-masked, multicenter, parallel-group clinical studies with similar entry criteria and protocols. In study 1 (two clinical trials), after washout of previous medications, patients with glaucoma or OHT were randomized to thrice-daily treatment with brimonidine P 0.15% (n = 381), brimonidine P 0.2% (n = 383), or brimonidine 0.2% (n = 383). In study 2 (one clinical trial), the treatment arms were thrice-daily brimonidine P 0.1% (n = 215) and brimonidine 0.2% (n = 218).

MAIN OUTCOME MEASURE

Treatment-related adverse events (AEs) and discontinuations due to AEs.

RESULTS

Treatment-related AEs were significantly reduced with brimonidine P 0.15% compared with brimonidine 0.2% in study 1 (p < 0.001). Treatment-related AEs and discontinuations due to AEs were significantly reduced with brimonidine P 0.1% compared with brimonidine 0.2% in study 2 (p < or = 0.014). In the meta-analysis of study 1 and study 2, the overall incidence of treatment-related AEs was lower with brimonidine P 0.1% than with brimonidine P 0.15% (41.4 vs. 49.7%; p = 0.050). Although the incidence of treatment-related ocular AEs was similar with brimonidine P 0.1% and 0.15% (p = 0.461), treatment-related systemic AEs were less frequent with brimonidine P 0.1% than with brimonidine P 0.15% (4.7 vs. 14.2%; p < 0.001), and there were fewer discontinuations due to systemic AEs with brimonidine P 0.1% than with brimonidine P 0.15% (p = 0.025).

CONCLUSIONS

Brimonidine P 0.1% has improved systemic safety and tolerability compared with brimonidine P 0.15%. The ocular safety and tolerability of the formulations are similar. The present meta-analysis is based on only two clinical studies, and additional studies further evaluating the safety and tolerability of these medications are warranted.