Ocular carteolol. A review of its pharmacological properties, and therapeutic use in glaucoma and ocular hypertension

Systemic side effects of glaucoma medications

Glaucoma is a progressive loss of retinal ganglion cells leading to visual field loss. Lowering intraocular pressure is currently the only modifiable risk factor to slow glaucoma progression. Intraocular pressure-lowering options include topical and systemic medications, lasers, and surgical procedures. Glaucoma eye drops play a major role in treating this blinding disease. Similar to all medications, the glaucoma medications have their own adverse effects. The majority of glaucoma medications work by stimulating or inhibiting adrenergic, cholinergic, and prostaglandin receptors, which are distributed all over the body. Therefore, the glaucoma medications can affect organs other than the eye. This review will discuss the systemic adverse effects of carbonic anhydrase inhibitors, sympathomimetics, para-sympathomimetics, beta blockers, prostaglandin analogs, hyperosmotic agents, and novel glaucoma medications with a stress on pregnant patients, breastfeeding mothers, and paediatric patients.

Comparison of the 24-h efficacy and safety of fixed combination carteolol/latanoprost and timolol/latanoprost in patients with primary open-angle glaucoma and ocular hypertension: a prospective crossover study

PURPOSE

To evaluate the 24-h efficacy and safety of fixed combination carteolol/latanoprost (LCFC) and timolol/latanoprost (LTFC) in patients with primary open-angle glaucoma and ocular hypertension.

STUDY DESIGN

Prospective, randomized, crossover study METHODS: Twenty-two patients pretreated with a prostaglandin analog at baseline were randomly assigned at a 1:1 ratio to either LCFC or LTFC treatment. The patients received the assigned study drug in both eyes daily in the evening (20:00). Each treatment group crossed over after a 2-month treatment period. The 24-h curves of intraocular pressure (IOP), pulse rate, and blood pressure were evaluated. Safety was also assessed.

RESULTS

The changes in mean daytime IOP from baseline at the end of the 2-month treatment period in the LCFC and LTFC groups were  - 0.93 and  - 1.15 mmHg, respectively. The changes in peak IOP in the 2 groups were  - 0.91 and  - 0.68 mmHg, respectively. The nighttime pulse rate in the LCFC group increased; that in the LTFC group was lower at all time points. The changes in pulse rate from baseline at 22:00, 2:00, 4:00, and 6:00 differed statistically between the 2 groups. No differences in changes from baseline in systolic and diastolic blood pressures were found between the groups.

CONCLUSION

The 24-h IOP curve of patients in the LCFC group was similar to that of the LTFC group, but on the basis of the pulse rate findings, the effect of LCFC on the cardiovascular system over 24 h was less than that of LTFC.

Ophthalmological features and treatments in five cases of Waardenburg syndrome

The present study aimed to investigate the ocular characteristics and treatment of Waardenburg syndrome (WS). A total of five patients with Waardenburg syndrome from our hospital, aged between 1 and 8 years, were included in the present study. The clinical data of these patients were analyzed, and the ocular manifestations and treatments were described. The general manifestations included hearing loss (1/5), broad high nasal root (2/5) and hypoplasia of alae nasi (2/5). Ophthalmological evaluations revealed ptosis (1/5), strabismus 1 (1/5), synophrys (2/5), telecanthus (5/5), iris hypopigmentation (5/5), high intraocular pressure (1/5) and choroidal hypopigmentation (1/5). For patients with characteristic external eye abnormalities, including ptosis, ocular plastic surgery was performed. For patients with only symptoms of iris heterochromia, no special treatment was required. The findings from the present study suggest that patients with WS may have several characteristic ocular manifestations. Abnormalities in the eyelid can be corrected by ocular plastic surgery, which is beneficial to children's physical and mental development.

Fixed Combination of Carteolol and Pilocarpine Eye-Drops: A Double-Blind Randomized Cross-Over Trial versus Carteolol Alone on Intra-Ocular Pressure

The effects of carteolol 2% and a fixed combination of carteolol 2% and pilocarpine 2% (CBS 341 A) eye-drops on intraocular pressure (I.O.P.) were compared in a multicenter double-blind, cross-over prospective trial. Twenty-eight patients were initially selected after at least three weeks of carteolol 2%, with a morning I.O.P. greater than 21-mmHg. They received 2 drops a day (b.i.d.), in a random order, alternating two weeks of carteolol 2% alone or two weeks of CBS 341 A. After each two-week period a 12-h I.O.P. curve was plotted. Compared to carteolol the combination reduced I.O.P. on average by around 20% (4 mmHg), with maximum effect 4h after instillation. The effectiveness was confirmed after twelve hours. Some side effects were reported with CBS 341 A, due to the well known pharmacological effects of pilocarpine. The new combination could be useful for second-line therapy in glaucoma.

Carteolol hydrochloride suppresses the generation of reactive oxygen species and rescues cell death after ultraviolet irradiation of cultured lens epithelial cells

Introduction:

Anti-oxidant activities of adrenergic β-blockers are proposed in various organs. The aim of the present study was to investigate the effect of carteolol hydrochloride, an adrenergic β-blocker, on the production of reactive oxygen species (ROS) and the viable cell number after ultraviolet irradiation of cultured lens epithelial cells (LECs).

Materials and Methodology:

Cultured LECs were exposed to 0, 10^–5, 10^–4, and 10^–3 M carteolol hydrochloride for 30 min followed by ultraviolet B (UVB) irradiation at intensity of 100, 200, or 400 mJ/cm². The amount of ROS in the LECs was measured using dichlorodihydrofluorescein at 30 min after exposure to UVB. In addition, the number of living LECs was counted at 15 h after exposure to UVB.

Results:

Exposure to 10^–3 M carteolol hydrochloride significantly decreased the amount of ROS after exposure to UVB at intensities of 100, 200, and 400 mJ/cm². In addition, 10^–3 M carteolol hydrochloride significantly increased the viable cell number after exposure to UVB at 400 mJ/cm². However, 10^–4 and 10^–5M carteolol hydrochloride had no significant effect on ROS or the viable cell number in LECs.

Discussions:

Carteolol hydrochloride protects LECs against UVB irradiation by inhibiting the intracellular production of ROS.

Environmentally Responsive Ophthalmic Gel Formulation of Carteolol Hydrochloride

Environmentally responsive gel formulation for ocular controlled delivery of carteolol hydrochloride (HCl) was developed in an attempt to improve ocular bioavailability and hence decrease its systemic absorption and side effects. The viscosity and the ability of the prepared formulations to deliver carteolol HCl in vitro and in vivo were monitored and compared with an aqueous commercial solution. The effect of polymer concentration and drug concentration on the in vitro release of carteolol HCl was examined. Gelrite formulations showed pseudoplastic behavior with thixotropic characteristics and the viscosity of the prepared systems increased as the concentration of the polymer increased. At fixed drug concentrations, as the Gelrite concentration increased, the drug release decreased. At fixed polymer concentrations, as the drug concentration increased the release of drug increased. Gelrite formulation (0.4% w/w) containing 1% drug showed significantly improved bioavailability compared with the commercial aqueous solution (Arteoptic 1%). The developed in situ gel formulation showed potential for use as delivery systems with superior ocular bioavailability of carteolol HCl.

Cardiovascular and respiratory considerations with pharmacotherapy of glaucoma and ocular hypertension

Glaucoma and ocular hypertension are highly prevalent conditions in individuals over the age of 40 and are commonly seen together in patients with cardiovascular disease. Many of the antiglaucoma medications, when systemically absorbed, affect the sympathetic and parasympathetic nervous systems of patients and can cause cardiovascular toxicity. Such adverse effects are frequently associated with the long-term use of potentially toxic agents in elderly people, who are most prone to chronic eye disease. Moreover, patients may not associate their symptoms with the topical eye medications, and consequently may not report adverse drug effects. Drug-drug interactions can also occur when patients are taking medications for both cardiovascular disease and glaucoma. In this review, the systemic toxicity of these agents is reviewed, along with possible drug-drug interactions. Mention is made of other antiglaucoma medications used alone and in combination with topical beta-blockers. Identification of genetic loci-a bold new step toward glaucoma treatment-is mentioned briefly at the end of the article.

Ocular Carteolol

Ocular carteolol (Mikelan), Teoptic, Ocupress) is a nonselective beta-adrenoceptor antagonist with intrinsic sympathomimetic activity (ISA). Ocular carteolol effectively reduces intraocular pressure (IOP) in patients with open-angle glaucoma (OAG) or ocular hypertension (OH). Twice-daily administration of standard carteolol has generally similar IOP-lowering efficacy to other ocular beta-adrenoceptor antagonists such as timolol, betaxolol and metipranolol in patients with OAG or OH. In addition, long-term treatment with carteolol has similar efficacy to timolol and betaxolol in terms of reducing IOP and maintaining visual fields in patients with newly diagnosed primary OAG (POAG). The new long-acting formulation of once-daily carteolol has equivalent efficacy to the standard formulation of carteolol administered twice daily in patients with OAG or OH. Both the standard and long-acting formulations of ocular carteolol are generally well tolerated in terms of topical adverse effects involving the eyes or systemic adverse effects involving the cardiovascular system. Thus, twice-daily carteolol is a well established option in the treatment of glaucoma and OH, and the new once-daily formulation of long-acting carteolol offers similar efficacy and tolerability with a potential for improved patient adherence.

Cardiovascular considerations in using topical, oral, and intravenous drugs for the treatment of glaucoma and ocular hypertension: focus on beta-adrenergic blockade

Glaucoma and ocular hypertension are highly prevalent conditions in individuals over the age of 40 and are commonly seen together in patients with cardiovascular disease. Many of the antiglaucoma medications, when systemically absorbed, affect the sympathetic and parasympathetic nervous systems of patients and can cause cardiovascular toxicity. Such adverse effects are frequently associated with the long-term use of potentially toxic agents in elderly people, who are most prone to chronic eye disease. Moreover, patients may not associate their symptoms with the topical eye medications, and consequently may not report adverse drug effects. Drug-drug interactions can also occur when patients are taking medications for both cardiovascular disease and glaucoma. This review focuses on beta-adrenergic blockers as topical antiglaucoma medications and other topical antiglaucoma drugs. The systemic toxicity of these agents is reviewed, along with the possible drug interactions. Brief mention is also made of other antiglaucoma medications used alone and in combination with topical beta-blockers.

Pharmacological therapy for glaucoma: a review

For some time the medical treatment of glaucoma has consisted of topical beta-blockers, adrenergic agents, miotics and oral carbonic anhydrase inhibitors (CAIs). However, the therapeutic arsenal available for the medical treatment of glaucoma has recently extended with new classes of ocular hypotensive agents i.e. prostaglandins, local CAIs and alpha2-adrenergic agents. Beta-blockers are still the mainstay in glaucoma treatment and are first line drugs. However, even if they are applied once daily, as with timolol in gel forming solution and levobunolol, the possible cardiopulmonary adverse effects of beta-blockers remain a cause for concern. When monotherapy with beta-blockers is ineffective in reducing intraocular pressure (IOP) or is hampered by adverse effects, a change of monotherapy to prostaglandins, local CAIs, alpha2-adrenergic agonists (brimonidine) or to dipivalyl epinephrine is advised. Prostaglandins, local CAIs and alpha2-adrenergic agonists, such as brimonidine, may in time become first line drugs because they reduce IOP effectively and until now systemic adverse effects have rarely been reported with these agents. The development of a pro-drug of either a local CAI or an alpha2-adrenergic agonist with a sustained and continuous effect on IOP level, which could be applied once a day is suggested. Because of these new developments, miotics, i.e. pilocarpine and carbachol, are recommended as second or third line drugs. The cholinesterase inhibitors are considered third line drugs as better agents with fewer local and systemic adverse effects have become available. Oral CAIs may be used temporarily in patients with elevated IOPs e.g. postsurgery or post-laser, or continuously in patients with glaucoma resistant to other treatment. Combining ocular hypotensive drugs is indicated when the target pressure for an individual patient cannot be reached with monotherapy. Combination therapy of beta-blockers is additive with prostaglandins, topical CAIs and miotics. Prostaglandins such as latanoprost can be combined with beta-blockers, adrenergic agents, local CAIs and miotics. Combinations with brimonidine or local CAIs need further investigation. Treatment of glaucoma with the new ocular hypotensive agents, either in monotherapy or combination therapy, may provide lower IOPs and delay or postpone the need for surgery.

Short-term comparative study of topical 2% carteolol with and without benzalkonium chloride in healthy volunteers

AIM

A crossover, randomised double blind study was undertaken in 30 healthy volunteers, in order to compare the tolerance of 2% carteolol with and without preservative in short term use.

METHODS

Complete ophthalmic examinations were performed before and 30, 60, and 180 minutes after instillation of one drop of the solution, and after 3 days of preservative treatment. After a 5 day washout, the same examinations were done with the second drug.

RESULTS

Results showed good general tolerance for both formulations. No significant difference in subjective tolerance, corneal aesthesiometry, punctuate keratitis, Schirmer's test, intraocular pressure (IOP) decrease (about 25% in the two groups at 3 hours, 10% after 3 days of treatment), resting cardiac frequency, or blood pressure was observed. However, break up time was significantly reduced from baseline by preserved carteolol both at 3 hours (10.40 (5.9) seconds to 6.15 (3.9) seconds, p = 0.001) and after 3 days (7.72 (5.5) seconds, p = 0.04). Preservative free carteolol did not significantly change the break up time (baseline 9.08 (5.7) seconds; 3 hours = 7.88 (5.5) seconds, not significant; day 3 = 8.35 (5.8), non-significant).

CONCLUSIONS

These results confirm that carteolol is well tolerated, either with or without preservative. The preservative free group showed better stability of the tear film, without loss of effect on IOP. This difference, although mild in the healthy young subjects in the present study could be much more relevant in those patients treated long term, older patients, and/or those suffering from ocular surface disorders. In such instances, preservative free drugs could be of potential benefit to protect the lacrimal fluid integrity and corneoconjunctival surface.

Effects of pilocarpine and other antiglaucoma drugs on cultured human Tenon's fibroblast cells

It has been found that long-term therapy with topical antiglaucoma drugs may decrease the success of glaucoma filtering surgery. In this study, various antiglaucoma drugs, including carteolol, betaxolol, levobunolol, pilocarpine, and timolol, were investigated for their proliferative effect on cultured human Tenon's fibroblast cells. It was found that the 3H-thymidine uptake of cultured fibroblast cells was inhibited by commercial antiglaucoma drugs, including carteolol of 0.1% concentration (13%), 0.01% (50%) and 0.001% (53%), betaxolol of 0.05% concentration (14%), 0.005% (42%) and 0.0005% (62%), levobunolol of 0.05% concentration (2%), 0.005% (32%) and 0.0005% (55%), and timolol of 0.025% concentration (4%), 0.0025% (47%) and 0.00025% (55%), whereas the 3H-thymidine uptake was increased by commercial pilocarpine eyedrop from 103% (0.2% of concentration), 170% (0.02% of concentration) to 171% (0.002% of concentration), when cells were treated with commercial drugs for 100 min. Meanwhile, the proliferations of cultured fibroblast cells were stimulated by simultaneously combining 0.2%, 0.02% and 0.002% concentrations of pilocarpine eyedrops with other antiglaucoma drugs, such as carteolol of 0.1% concentration (50%), 0.01% (113%) and 0.001% (138%), betaxolol of 0.05% concentration (24%), 0.005% (128%) and 0.0005% (142%), levobunolol of 0.05% concentration (32%), 0.005% (87%) and 0.0005% (119%), and timolol of 0.025% concentration (15%), 0.0025% (94%) and 0.00025% (118%). Following incubation with pure pilocarpine, the proliferation of Tenon's fibroblast cells was inhibited for 84% (0.2% concentration), 84% (0.02% concentration) and 90% (0.002% concentration). When fibroblast cells were treated with commercial pilocarpine eyedrops for 24 hours, the 3H-thymidine uptake was increased to 160% (0.02% concentration) and 172% (0.002% concentration). This result shows that the commercial pilocarpine may play a crucial role for the proliferation of cultured human Tenon's fibroblast cells.

Comparison of the ocular beta-blockers

OBJECTIVE

To compare the similarities and differences among the ocular beta-blockers. Important considerations when comparing these agents are the differences in systemic adverse effects, local tolerability, and cost.

DATA SOURCE

Information was retrieved from a MEDLINE search of the English-language literature and bibliographic reviews of review articles. Index terms included beta-blockers, glaucoma, timolol, levobunolol, betaxolol, metipranolol, and carteolol.

STUDY SELECTION

Emphasis was placed on eyedrop studies, as well as properly designed and executed clinical trials that assessed dosage, dosing interval, therapeutic response, adverse effects, and cost.

DATA EXTRACTION

Data from several studies were evaluated according to the study design, therapeutic response, and adverse effects.

DATA SYNTHESIS

Timolol maleate, levobunolol, metipranolol, and carteolol have similar effectiveness in lowering intraocular pressure; however, levobunolol and timolol gel forming solution may have an advantage of once-daily dosing. Studies have not been published comparing the clinical efficacy of timolol hemihydrate with that of other ocular beta-blockers. Metipranolol is cost effective in treating primary open-angle glaucoma; however, it has been associated with more ocular burning, stinging, and granulomatous anterior uveitis than other agents. The intrinsic sympathomimetic activity of carteolol has not yet displayed a definite advantage over the other agents in terms of optic disk perfusion and systemic adverse effects. The control of intraocular pressure with betaxolol has not always been as good as with timolol; however, betaxolol has some advantages over timolol and the other topical beta-blockers in terms of systemic adverse effects.

CONCLUSIONS

Considering cost, efficacy, and safety, timolol maleate is the recommended formulary agent because the other agents cannot consistently show an outstanding advantage.

Topical ophthalmic beta-adrenergic blockade for the treatment of glaucoma and ocular hypertension

Since the late 1970s, topical beta-adrenergic blockers have been the drugs of choice in treating ocular hypertension and associated glaucoma. The currently available drugs are timolol, betaxolol, levobunolol, metipranolol, and carteolol. All reduce intraocular pressure by decreasing the production of aqueous humor. Although these drugs are applied locally in the eye, they may enter the general circulation and reach concentrations high enough to cause systemic effects, including alterations in heart rate and rhythm, bronchoconstriction, dyslipidemia, and central nervous system abnormalities. Interactions with other drugs may also occur. Ocular beta- blockers differ in beta 1-selectivity (betaxolol is beta 1-selective, whereas the other drugs are nonselective) and in intrinsic sympathomimetic activity (ISA) or partial agonist properties (only carteolol possesses ISA). These differences give betaxolol and carteolol potential advantages in minimizing certain side effects. The advantage of betaxolol vis-à-vis systemic side effects is more clearly established than that of carteolol. Further systematic study is needed to determine what advantages, if any, are conferred by the presence of ISA.

Effects of ocular carteolol and timolol on plasma high-density lipoprotein cholesterol level

Fifty-eight healthy, normolipidemic adult men participated in a prospective, masked, randomized crossover study designed to compare the effects of two topical nonselective beta-adrenergic antagonists, carteolol and timolol, on plasma high-density lipoprotein cholesterol levels. Two eight-week treatment periods were separated by an eight-week drug-free period. Carteolol 1.0% or timolol 0.5% was used, one drop twice daily, in both eyes without nasolacrimal occlusion. Fresh plasma was assayed for levels of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and apolipoproteins A-I and B-100. With indistinguishable effects on intraocular pressure, carteolol and timolol induced different (P = .013) decrements in high-density lipoprotein cholesterol levels. Carteolol treatment decreased high-density lipoprotein cholesterol levels by 3.3% (-0.04 mmol/l) and raised the ratio of total to high-density lipoprotein cholesterol levels by 4.0% (0.15 unit); timolol treatment decreased high-density lipoprotein cholesterol levels by 8.0% (-0.10 mmol/l) and raised the ratio of total to high-density lipoprotein cholesterol levels by 10.0% (0.37 unit). There was no differential drug effect on the other lipid variables measured. Ocular nonselective beta-adrenergic antagonist therapy can produce clinically relevant decrements in high-density lipoprotein cholesterol levels in healthy men.

Topical ophthalmic beta blockers: a comparative review

Topically administered beta blockers are the preferred medical therapy for glaucoma. These agents reduce intraocular pressure (IOP), thereby preventing damage to the optic nerve and the subsequent loss of vision. Timolol, betaxolol, levobunolol, metipranolol, and carteolol are the topical beta blockers available in the U.S. They have similar IOP-lowering efficacy, but differ in other pharmacological properties. Topically administered beta blockers are generally well tolerated. They undergo systemic absorption, however, and can adversely affect cardiovascular and bronchopulmonary function in patients with existing diseases such as heart failure, sinus bradycardia, chronic obstructive airways disease, or asthma. Betaxolol, which is beta 1-selective, and carteolol, which has intrinsic sympathomimetic activity (ISA), may have systemic tolerability profiles superior to the traditional nonselective, non-ISA beta blockers. These hypotheses require confirmation in controlled clinical trials. Local adverse effects associated with beta blockers include stinging, burning, red eye, itching, tearing and loss of corneal sensitivity. Stinging upon instillation is a particularly frequent finding with betaxolol (up to 30% to 40% of patients). Preliminary evidence suggests that carteolol has the best local tolerability profile of these drugs.