Efficacy and safety of brimonidine and dorzolamide for intraocular pressure lowering in glaucoma and ocular hypertension

Pharmaceutical In Situ Gel for Glaucoma: Recent Trends and Development with an Update on Research and Patents

Glaucoma is a progressive visual polyneuropathy characterized by retinal ganglion cell atrophy and optic nerve head changes. It's generally triggered due to increased intraocular pressure compared with the healthy eye. Glaucoma is treated with various medications in traditional eye drops, such as prostaglandins, carbonic anhydrase inhibitors, beta-blockers, and others. Such treatments are difficult to use and produce lachrymal leakage and inadequate corneal permeability, resulting in lower availability. Ophthalmic in situ gels, introduced in past decades with tremendous effort, are among the finest various choices to solve the drawbacks of eye drops. Employing different polymers with pH-triggered, temperature-triggered, and ion-activated processes have been used to generate ophthalmic in situ gelling treatments. Once those preparations are delivered into the eye, they change phase from sol to gel, allowing the medicine to stay in the eye for longer. These formulations are known as smart gels as they turn into gelling fluids when administered into the eyes. The different mechanisms of in situ gel formulations are used for the management of glaucoma and are discussed in this review article.

Recent Trends in Treatment and Associated Costs of Primary Angle-Closure Glaucoma: A Retrospective Cohort Study

PURPOSE

To describe recent trends in the treatment for primary angle-closure glaucoma (PACG) and its associated costs in a clinical setting.

DESIGN

A retrospective cohort study.

SUBJECTS

We included patients with PACG from 2011 to 2020 using a large-scale administrative claims database in Japan.

METHODS

We calculated the frequencies and costs of antiglaucoma drugs, ophthalmic examinations, and glaucoma-related surgeries, stratified by fiscal years and age groups.

MAIN OUTCOME MEASURES

Frequencies and costs of antiglaucoma drugs, ophthalmic examinations, and glaucoma-related surgeries.

RESULTS

We identified 5654 patients with PACG (15 338 patient-years). Prostanoid FP receptor agonist, nonselective β-blocker, and topical carbonic anhydrase inhibitor use decreased, whereas prostanoid EP2 receptor agonist, α-2 adrenergic agonist, Rho-associated protein kinase inhibitor, and fixed-combination eyedrops use increased. The total amount of drug per patient-year significantly decreased. In recent years, the frequency of cataract surgery increased, whereas that of laser peripheral iridotomy decreased. Visual field testing, slit-lamp examination, intraocular pressure measurement, and funduscopy were performed 0.83, 6.65, 5.15, and 4.61 times/patient-year, respectively. The total cost of drugs, examinations, and surgeries was 60 338 yen per patient-year. Patients with PACG spent more than twice the money on surgeries and examinations than they did on antiglaucoma drugs.

CONCLUSION

The amount of antiglaucoma drugs dispensed decreased, and the proportion of fixed-combination and newly introduced eyedrops increased. Frequency of cataract surgery increased whereas that of laser peripheral iridotomy decreased in recent years. Surgeries and examinations were the major cost drivers for PACG treatment. The current results would be valuable information for future economic analyses and policy making.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

[Selective α2-agonists in the treatment of glaucoma: pharmacology, efficacy and safety]

Glaucoma is the main cause of irreversible blindness in the world. Among the hypotensive eye drops, an important place belongs to the selective α2-adrenergic receptor antagonist brimonidine. This part of the review focuses on key pharmacological and therapeutic characteristics of brimonidine and its mode of action. The article also discusses the side effects of brimonidine and the methods of their prevention.

Mechanochemical solid-state synthesis of 2-aminothiazoles, quinoxalines and benzoylbenzofurans from ketones by one-pot sequential acid- and base-mediated reactions

α-Chloroketones - obtained by the atom-economical chlorination of ketones with trichloroisocyanuric acid (TCCA) in the presence of p-TSA under ball-milling conditions - were set up for a sequential base-mediated condensation reaction with thiourea/thiosemicarbazides, o-phenylenediamine and salicylaldehyde to afford 2-aminothiazoles, 2-hydrazinylthiazoles, quinoxalines and benzoylbenzofurans, respectively, in respectable yields. The viability of one-pot sequential acid- and base-mediated reactions in the solid state under ball-milling conditions is thus demonstrated.

The effects of intravenous romifidine on intraocular pressure in clinically normal horses and horses with incidental ophthalmic findings

DESIGN

Original study.

OBJECTIVE

To evaluate the effect of sedation with romifidine hydrochloride 1% (Sedivet: Boehringer-Ingelheim) on intraocular pressure (IOP) in the normal horse and horses with incidental ophthalmic findings as measured by applanation tonometry.

ANIMALS

Nineteen clinically normal horses (13 geldings, six mares) and eight horses (three geldings, five mares) with incidental ophthalmic findings were included in this study.

PROCEDURES

All horses underwent complete ophthalmic examination with pharmacologic mydriasis a minimum of 2 weeks prior to IOP evaluation. Baseline intraocular pressure values were obtained following auriculopalpebral nerve block and topical anesthetic. Immediately thereafter, romifidine was administered intravenously (75 µg/kg) and the IOP recorded at 5, 15, 30, 45 and 60 min postsedation in both eyes. Five successive readings were obtained at each time point, the low and high value discarded, and three remaining readings averaged for a mean.

RESULTS

The changes with time were consistent between eyes and OD and OS results were pooled. The mean IOP at baseline was 26.35 ± 5.57 mmHg. Mean IOP values were significantly lower than baseline at 5 (P < 0.0001), 15 (P < 0.0001), 30 (P = 0.0003), 45 (P < 0.0001) and 60 (P = 0.0005) minutes. The largest change from baseline (16.7%) was noted at t = 15 min.

CONCLUSIONS AND CLINICAL RELEVANCE

Administration of romifidine significantly decreased the IOP from baseline at all time points measured. The greatest decline in IOP was noted at 15 min postsedation. Results are consistent with other studies noting a decline in IOP with administration of α-2 agonists.

Safety of carbonic anhydrase inhibitors

INTRODUCTION

Carbonic anhydrase (CA) inhibitors have an impressive safety record despite the multiple functions that CA isozymes serve because they are not fully inhibited with most dosing. While reducing the targeted CA-dependent process sufficiently for disease control, residual activity and uncatalyzed rates in combination with compensations are adequate to avoid lethal consequences. Some drugs have in vitro selectivity differences against the 13 active isozymes, but none are convincingly selective in vivo or clinically. Efforts to synthesize selective inhibitors should result in safer drugs with fewer side effects.

AREAS COVERED

This review will focus on approved drugs with CA-inhibiting activity, whether used directly for this purpose or others. Side effects are discussed in relation to various organ systems and the disease being treated. Causes of side effects are considered, and strategies for symptom reduction are given.

EXPERT OPINION

Common side effects of paresthesias, dyspepsia, lassitude and fatigue in 30 - 40% of patients are generally tolerable or abate, but if not can be partially relieved by bicarbonate supplementation. The most important safety concerns are severe acidosis, respiratory failure and encephalopathy in patients with renal, pulmonary and hepatic disease where caution is critical, as is also the case in persons with sulfa drug allergies.

What comparative effectiveness research is needed? A framework for using guidelines and systematic reviews to identify evidence gaps and research priorities

The authors developed and tested a framework for identifying evidence gaps and prioritizing comparative effectiveness research by using a combination of clinical practice guidelines and systematic reviews. In phase 1 of the project, reported elsewhere, 45 clinical questions on the management of primary open-angle glaucoma were derived from practice guidelines and prioritized by using a 2-round Delphi survey of clinicians. On the basis of the clinicians' responses, 9 questions were classified as high-priority. In phase 2, reported here, systematic reviews that addressed the 45 clinical questions were identified. The reviews were classified as at low, high, or unclear risk of bias, and evidence gaps (in which no systematic review was at low risk of bias) were identified. The following comparative effectiveness research agenda is proposed: Two of the 9 high-priority questions require new primary research (such as a randomized, controlled trial) and 4 require a new systematic review. The utility and limitations of the framework and future adaptations are discussed.

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.

Molecular clustering identifies complement and endothelin induction as early events in a mouse model of glaucoma

Glaucoma is one of the most common neurodegenerative diseases. Despite this, the earliest stages of this complex disease are still unclear. This study was specifically designed to identify early stages of glaucoma in DBA/2J mice. To do this, we used genome-wide expression profiling of optic nerve head and retina and a series of computational methods. Eyes with no detectable glaucoma by conventional assays were grouped into molecularly defined stages of disease using unbiased hierarchical clustering. These stages represent a temporally ordered sequence of glaucoma states. We then determined networks and biological processes that were altered at these early stages. Early-stage expression changes included upregulation of both the complement cascade and the endothelin system, and so we tested the therapeutic value of separately inhibiting them. Mice with a mutation in complement component 1a (C1qa) were protected from glaucoma. Similarly, inhibition of the endothelin system with bosentan, an endothelin receptor antagonist, was strongly protective against glaucomatous damage. Since endothelin 2 is potently vasoconstrictive and was produced by microglia/macrophages, our data provide what we believe to be a novel link between these cell types and vascular dysfunction in glaucoma. Targeting early molecular events, such as complement and endothelin induction, may provide effective new treatments for human glaucoma.

Control of intracellular calcium signaling as a neuroprotective strategy

Both acute and chronic degenerative diseases of the nervous system reduce the viability and function of neurons through changes in intracellular calcium signaling. In particular, pathological increases in the intracellular calcium concentration promote such pathogenesis. Disease involvement of numerous regulators of intracellular calcium signaling located on the plasma membrane and intracellular organelles has been documented. Diverse groups of chemical compounds targeting ion channels, G-protein coupled receptors, pumps and enzymes have been identified as potential neuroprotectants. The present review summarizes the discovery, mechanisms and biological activity of neuroprotective molecules targeting proteins that control intracellular calcium signaling to preserve or restore structure and function of the nervous system. Disease relevance, clinical applications and new technologies for the identification of such molecules are being discussed.

Three-month, randomized, parallel-group comparison of brimonidine-timolol versus dorzolamide-timolol fixed-combination therapy

OBJECTIVE

Fixed combinations of 0.2% brimonidine-0.5% timolol and 2% dorzolamide-0.5% timolol are used to lower intraocular pressure (IOP). The objective of this study was to evaluate the IOP-lowering efficacy and ocular tolerability of brimonidine-timolol compared with dorzolamide-timolol when used as monotherapy or as adjunctive therapy to a prostaglandin analog (PGA) in patients with glaucoma or ocular hypertension.

STUDY DESIGN AND METHODS

Pooled data analysis of two randomized, investigator-masked, 3-month, parallel-group studies with identical protocols (ten sites). In all, 180 patients with open-angle glaucoma or ocular hypertension who were in need of lower IOP received topical brimonidine-timolol BID or dorzolamide-timolol BID as monotherapy (n = 101) or as adjunctive therapy to a PGA (latanoprost, bimatoprost, or travoprost) (n = 79).

CLINICAL TRIAL REGISTRATION

The studies are registered with the identifiers NCT00822081 and NCT00822055 at http://www.clinicaltrials.gov.

MAIN OUTCOME MEASURES

IOP was measured at 10 a.m. (peak effect) at baseline and at months 1 and 3. Tolerability/comfort was evaluated using a patient questionnaire.

RESULTS

There were no statistically significant between-group differences in patient demographics. Most patients were Caucasian, and the mean age was 68 years. There were also no statistically significant differences between treatment groups in baseline IOP. At month 3, the mean (SD) reduction from baseline IOP for patients on fixed-combination monotherapy was 7.7 (4.2) mmHg (32.3%) with brimonidine-timolol versus 6.7 (5.0) mmHg (26.1%) with dorzolamide-timolol (p = 0.040). The mean reduction from PGA-treated baseline IOP for patients on fixed-combination adjunctive therapy was 6.9 (4.8) mmHg (29.3%) with brimonidine-timolol versus 5.2 (3.7) mmHg (23.5%) with dorzolamide-timolol (p = 0.213). Patients on brimonidine-timolol reported less burning (p < 0.001), stinging (p < 0.001), and unusual taste (p < 0.001) than patients on dorzolamide-timolol.

CONCLUSIONS

Fixed-combination brimonidine-timolol provided the same or greater IOP lowering compared with fixed-combination dorzolamide-timolol. Both fixed-combination medications were safe and well-tolerated. Brimonidine-timolol received higher ratings of ocular comfort than dorzolamide-timolol. The duration of the studies was 3 months, and additional studies will be needed to compare the efficacy and tolerability of brimonidine-timolol and dorzolamide-timolol during long-term treatment.