Ocular hypotensive efficacy of brimonidine 0.15% as adjunctive therapy with latanoprost 0.005% in patients with open-angle glaucoma or ocular hypertension

How latanoprost changed glaucoma management

Glaucoma is currently considered one of the leading causes of severe visual impairment and blindness worldwide. Topical medical therapy represents the treatment of choice for many glaucoma patients. Introduction of latanoprost, 25 years ago, with an entirely new mechanism of action from that of the antiglaucoma drugs used up to that time was a very important milestone. Since then, due mainly to their efficacy, limited systemic side effects and once daily dosing, prostaglandin analogues (PGAs) have become as the first-choice treatment for primary open-angle glaucoma. PGAs are in general terms well tolerated, although they are associated with several mild to moderate ocular and periocular adverse events. Among them, conjunctival hyperemia, eyelash changes, eyelid pigmentation, iris pigmentation and hypertrichosis around the eyes are the most prevalent. The objective of this paper is to review the role of PGAs in the treatment of glaucoma over the 25 years since the launch of Latanoprost and their impact on clinical practice outcomes.

Topical Medication Therapy for Glaucoma and Ocular Hypertension

Glaucoma is one of the most common causes of blindness, thus seriously affecting people’s health and quality of life. The topical medical therapy is as the first line treatment in the management of glaucoma since it is inexpensive, convenient, effective, and safe. This review summarizes and compares extensive clinical trials on the topical medications for the treatment of glaucoma, including topical monotherapy agents, topical fixed-combination agents, topical non-fixed combination agents, and their composition, mechanism of action, efficacy, and adverse effects, which will provide reference for optimal choice of clinical medication. Fixed-combination therapeutics offer greater efficacy, reliable security, clinical compliance, and tolerance than non-fixed combination agents and monotherapy agents, which will become a prefer option for the treatment of glaucoma. Meanwhile, we also discuss new trends in the field of new fixed combinations of medications, which may better control IOP and treat glaucoma.

Efficacy and Safety of Switching from Prostaglandin Analog Therapy to Prostaglandin / Timolol Fixed Combination or Prostaglandin / Brimonidine Therapy

Background:

To compare the safety and efficacy between switching to prostaglandin/timolol fixed combination eye drops (PG/timolol FCs) and adding brimonidine to PG analogue monotherapy.

Methods:

Eyes of 53 patients with primary open-angle glaucoma or ocular hypertension who were receiving PG analogue monotherapy were included. Participants were randomly divided into two treatment groups: one was prescribed PG/timolol FCs (switched group), and for the other, 0.1% brimonidine was added to the PG analogue (added group). Intraocular pressure (IOP), blood pressure, and pulse rate were measured after 1 and 3 months and compared to baseline values. Participants were also surveyed to determine if they had experienced systemic or topical adverse events at each study visit. IOP changes at 1 and 3 months were compared between groups.

Results:

Three months after changing medication, mean IOP was 14.6 ± 2.4 mmHg in the switched group and 13.7 ± 1.8 mmHg in the added group; both were significantly lower than the baseline values (switched group, 16.5 ± 2.7 mmHg; added group, 15.8 ± 2.3 mmHg; both P < 0.001). Neither the mean nor the percentage reductions in IOP were significantly different between groups at 1 and 3 months. In the added group, diastolic blood pressure was lower than that at 1 and 3 months, systolic blood was lower than that at 3 months (P < 0.01). The patients who had experienced systemic or topical adverse events were 53.8% in the added group and 40.7% in the the changed group, which was equivalent between groups (P =0.4142). Three patients (11.5%) in the added group, but none from the switched group, were excluded from analyses because of adverse events (not significant, P = 0.217).

Conclusion:

Switching from a PG analogue to PG/timolol FCs or to PG with brimonidine was equally safe (systemically and topically) and effective in reducing IOP. Thus, PG with brimonidine might be appropriate medication in patients who cannot use PG/timolol FCs due to repiratory or circulatory disease.

Intraocular pressure-lowering combination therapies with prostaglandin analogues

Intraocular pressure (IOP) reduction is currently the only therapeutic approach demonstrated to preserve visual function in patients with glaucoma. The first line of glaucoma treatment consists of topical IOP-lowering medications, usually initiated as monotherapy. A significant proportion of patients require more than one medication to reach a target IOP at which optic nerve damage will not progress. As prostaglandin analogues (PGAs) are the most effective class for reducing IOP, one of the other commonly used classes (β-adrenoceptor antagonist [β-blocker], carbonic anhydrase inhibitor or α(2)-adrenoceptor agonist) is frequently combined with a PGA. In the last decade, the use of fixed combinations containing two medications in a single bottle has steadily increased. Fixed combinations have the potential to simplify the dosing regimen, increase patient adherence, avoid the washout effect of the second drop on the first medication instilled, decrease exposure to preservatives and, sometimes, reduce the cost of treatment. Clinical trials have evaluated PGA-based fixed combinations versus unfixed combinations (individual components administered concomitantly) or versus individual monotherapies; however, any advantage that the fixed combinations may have in terms of IOP-lowering efficacy is still debated. For these reasons, the PGA-based fixed combinations are not approved by regulatory authorities in some countries, such as the US. We review the published studies evaluating the efficacy and tolerability of the IOP-lowering unfixed and fixed combination therapies with PGAs. Regarding unfixed combinations, the review shows that α(2)-adrenergic agonists-PGA and carbonic anhydrase inhibitor-PGA combinations seem to be at least as effective at reducing IOP as the β-blocker-PGA combinations. As for the fixed combinations, the review shows that the three PGA-timolol fixed combinations are more effective than their component medications used separately as monotherapy and are better tolerated than the three respective prostaglandins. The three PGA-timolol fixed combinations are less effective at reducing IOP than the unfixed combinations but are better tolerated. The advantage of the fixed combinations in terms of patient adherence and persistence is supported by a very small number of studies and remains to be more accurately determined. Most studies, but not all, seem to show that PGA-timolol fixed combinations are more effective than other available β-blocker fixed combinations (dorzolamide-timolol fixed combinations) at reducing IOP and are similarly tolerated.