Neuropsychiatric Adverse Events from Topical Ophthalmic Timolol

A national analysis of systemic adverse events of beta-blockers used for glaucoma therapy

PURPOSE

To evaluate systemic complications for timolol, carteolol, levobunolol, and/or betaxalol by using an FDA Federal Adverse Event Reporting System (FAERS).

METHODS

We evaluated FAERS for adverse events associated with β-blocker use for glaucoma. All reported symptoms were reviewed to identify systemic adverse events and to detect safety signals, defined as information on a new or known side effect that may be caused by a medicine. We used the proportional reporting ratio (PRR), reporting odds ratio (ROR), empirical Bayes geometric mean (EBGM), and information component (IC) as a part of a disproportionality analysis comparing the frequency of β-blocker symptoms with all other adverse event reports. We considered a signal to be detected when all four disproportionality analysis metrics were positive.

RESULTS

We found 10,500,309 total adverse event reports from the FAERS database 2004-2022Q3, which included 8,793 case reports with a primary suspect of a β-blocker use for glaucoma. 1,838 unique adverse symptoms were reported were associated with β-blocker. Regarding outcomes, there were 165 (1.88%) reports of disability, 671 (7.63%) reports of hospitalisation, and 1,934 (21.99%) reports of some other unspecified complication. Regarding adverse events, the most reported general, cardiac, and respiratory symptoms were respectively dizziness (n = 281), bradycardia (n = 145), and dyspnoea (n = 195). 256 (2.91%) cases of death were reported. We found significant signals on bradycardia (n = 145), complete atrioventricular block (n = 38), and bronchospasm (n = 23). No allergic, endocrine, constitutional, or gastrointestinal symptoms generated positive signals.

CONCLUSION

β-blocker use in glaucoma therapy can be rarely associated with serious systemic and life-threatening complications.

Ocular Surface Fluid: More than a Matrix

Although the eye can be subjected to therapeutic manipulation, some of its structures are highly inaccessible. Thus, conventional therapeutic administration pathways, such as topical or systemic routes, usually show significant limitations in the form of low ocular penetration or the appearance of side effects linked to physiology, among others. The critical feature of many xenobiotics is the drug gradient from the concentrated tear reservoir to the relatively barren corneal and conjunctival epithelia, which forces a passive route of absorption. The same is true in the opposite direction, towards the ocular surface (OS). With the premise that tears can be regarded as equivalent to or a substitute for plasma, researchers may determine drug concentrations in the OS fluid. Within this framework, a survey of scholarly sources on the topic was conducted. It provided an overview of current knowledge, allowing the identification of relevant theories, methods, and gaps in the existing research that can be employed in subsequent research. OS fluid (tears particularly) has enormous potential as a source of biological material for external drug screening and as a biomarker of various systemic diseases. Given the numerous alternate matrices, knowledge of their properties is very important in selecting the most appropriate specimens in toxicological analyses.

Application of Quality by Design in the Development of Hydrogen Sulfide Donor Loaded Polymeric Microparticles

Hydrogen sulfide (H2S) is a multifaceted gasotransmitter molecule which has potential applications in many pathological conditions including in lowering intraocular pressure and providing retinal neuroprotection. However, its unique physicochemical properties pose several challenges for developing its efficient and safe delivery method system. This study aims to overcome challenges related to H2S toxicity, gaseous nature, and narrow therapeutic concentrations range by developing polymeric microparticles to sustain the release of H2S for an extended period. Various formulation parameters and their interactions are quantitatively identified using Quality-by-Design (QbD) approach to optimize the microparticle-based H2S donor (HSD) delivery system. Microparticles were prepared using a solvent-evaporation coacervation process by using polycaprolactone (PCL), soy lecithin, dichloromethane, Na2S.9H2O, and silicone oil as polymer, surfactant, solvent, HSD, and dispersion medium, respectively. The microparticles were characterized for size, size distribution, entrapment efficiency, and H2S release profile. A Main Effects Screening (MES) and a Response Surface Design (RSD) model-based Box-Behnken Design (BBD) was developed to establish the relationship between critical process parameters (CPPs) and critical quality attributes (CQAs) qualitatively and quantitatively. The MES model identified polymer to drug ratio and dispersion medium quantity as significant CPPs among others, while the RSD model established their quantitative relationship. Finally, the target product performance was validated by comparing predicted and experimental outcomes. The QbD approach helped in achieving overall desired microparticle characteristics with fewer trials and provided a mathematical relationship between the CPPs and the CQAs useful for further manipulation and optimization of release profile up to at least 30 days.

Unmet needs in glaucoma therapy: The potential role of hydrogen sulfide and its delivery strategies

Glaucoma is an optic neuropathy disorder marked by progressive degeneration of the retinal ganglion cells (RGC). It is a leading cause of blindness worldwide, prevailing in around 2.2% of the global population. The hallmark of glaucoma, intraocular pressure (IOP), is governed by the aqueous humor dynamics which plays a crucial role in the pathophysiology of the diesease. Glaucomatous eye has an IOP of more than 22 mmHg as compared to normotensive pressure of 10-21 mmHg. Currently used treatments focus on reducing the elevated IOP through use of classes of drugs that either increase aqueous humor outflow and/or decrease its production. However, effective treatments should not only reduce IOP, but also offer neuroprotection and regeneration of RGCs. Hydrogen Sulfide (H₂S), a gasotransmitter with several endogenous functions in mammalian tissues, is being investigated for its potential application in glaucoma. In addition to decreasing IOP by increasing aqueous humor outflow, it scavenges reactive oxygen species, upregulates the cellular antioxidant glutathione and protects RGCs from excitotoxicity. Despite the potential of H₂S in glaucoma, its delivery to anterior and posterior regions of the eye is a challenge due to its unique physicochemical properties. Firstly, development of any delivery system should not require an aqueous environment since many H₂S donors are susceptible to burst release of the gas in contact with water, causing potential toxicity and adverse effects owing to its inherent toxicity at higher concentrations. Secondly, the release of the gas from the donor needs to be sustained for a prolonged period of time to reduce dosing frequency as per the requirements of regulatory bodies. Lastly, the delivery system should provide adequate bioavailability throughout its period of application. Hence, an ideal delivery system should aim to tackle all the above challenges related to barriers of ocular delivery and physicochemical properties of H₂S itself. This review discusses the therapeutic potential of H₂S, its delivery challenges and strategies to overcome the associated chalenges.

Stable Gastric Pentadecapeptide BPC 157 Therapy of Rat Glaucoma

Cauterization of three episcleral veins (open-angle glaucoma model) induces venous congestion and increases intraocular pressure in rats. If not upgraded, one episcleral vein is regularly unable to acquire and take over the whole function, and glaucoma-like features persist. Recently, the rapid upgrading of the collateral pathways by a stable gastric pentadecapeptide BPC 157 has cured many severe syndromes induced by permanent occlusion of major vessels, veins and/or arteries, peripherally and centrally. In a six-week study, medication was given prophylactically (immediately before glaucoma surgery, i.e., three episcleral veins cauterization) or as curative treatment (starting at 24 h after glaucoma surgery). The daily regimen of BPC 157 (0.4 µg/eye, 0.4 ng/eye; 10 µg/kg, 10 ng/kg) was administered locally as drops in each eye, intraperitoneally (last application at 24 h before sacrifice) or per-orally in drinking water (0.16 µg/mL, 0.16 ng/mL, 12 mL/rat until the sacrifice, first application being intragastric). Consequently, all BPC 157 regimens immediately normalized intraocular pressure. BPC 157-treated rats exhibited normal pupil diameter, microscopically well-preserved ganglion cells and optic nerve presentation, normal fundus presentation, normal retinal and choroidal blood vessel presentation and normal optic nerve presentation. As leading symptoms, increased intraocular pressure and mydriasis, as well as degeneration of retinal ganglion cells, optic nerve head excavation and reduction in optic nerve thickness, generalized severe irregularity of retinal vessels, faint presentation of choroidal vessels and severe optic nerve disc atrophy were all counteracted. In conclusion, we claim that the reversal of the episcleral veins cauterization glaucoma appeared as a consequence of the BPC 157 therapy of the vessel occlusion-induced perilous syndrome.

Brimonidine Eye Drops Causing Encephalopathy in a Patient With Advanced Chronic Kidney Disease

Brimonidine eye drops are frequently prescribed for the treatment of glaucoma and ocular hypertension in adults. Systemic toxicities including neurological side effects have been reported with its use, especially in the paediatric population. In this report, we present a case of encephalopathy secondary to the use of brimonidine eye drops in a patient with underlying advanced chronic kidney disease, who recovered promptly after drug cessation. Herein, we also review the pharmacokinetics of eye drops leading to their systemic side effects, especially in the context of renal impairment. We also explore the possibility of extracorporeal treatment, such as by haemodialysis, for the treatment of these manifestations. This case demonstrates the need to clarify a patient’s drug history and stop offending medications early on in a patient with delirium, while treatments such as antidotes or extracorporeal treatment are being considered.