A double-masked, randomized 1-year study comparing dorzolamide (Trusopt), timolol, and betaxolol. International Dorzolamide Study Group

OBJECTIVE

To investigate the safety profile and efficacy of 2.0% dorzolamide hydrochloride, when administered three times daily for up to 1 year, compared with that of 0.5% timolol maleate and 0.5% betaxolol hydrochloride, each administered twice daily. In addition, the effect of adding dorzolamide to the regimen of patients with inadequate ocular hypotensive efficacy while they were receiving one of the two beta-adrenoceptor antagonists and the effect of adding timolol to the regimen of patients receiving dorzolamide were also evaluated.

DESIGN

A double-masked, randomized, parallel comparison.

SETTING

Multinational study at 34 international sites.

PATIENTS

Five hundred twenty-three patients with open-angle glaucoma or ocular hypertension, 17 to 85 years of age. Patients currently using ocular hypotensive medications were required to undergo a washout.

INTERVENTION

Two percent dorzolamide three times a day, 0.5% timolol (Timoptic, Merck, Whitehouse Station, NJ) twice daily, and 0.5% betaxolol solution (Betoptic, Alcon, Fort Worth, Tex) twice daily.

RESULTS

At 1 year, the mean percent reduction in intraocular pressure at peak of 2% dorzolamide, 0.5% timolol, and 0.5% betaxolol was approximately 23%, 25%, and 21%, respectively. At afternoon trough, the mean percent reduction in intraocular pressure was 17%, 20%, and 15% for dorzolamide, timolol, and betaxolol, respectively.

CONCLUSIONS

The ocular hypotensive efficacy of 2.0% dorzolamide, given three times a day, is comparable with that of 0.5% betaxolol, given twice daily, for up to 1 year. In addition, long-term use of dorzolamide was not associated with clinically meaningful electrolyte disturbances or systemic side effects commonly observed with the use of oral carbonic anhydrase inhibitors.

Adverse effects of topical antiglaucoma drugs on the ocular surface

PURPOSE

This study was designed to determine the effect of long-term antiglaucoma topical medication on the ocular surface; measuring basal Schirmer's and tear break-up time tests using conjunctival impression cytology.

METHODS

The ocular surfaces of 30 control subjects (group 1), 24 primary open-angle glaucoma patients treated with 0.5% betaxolol hydrochloride (group 2), 27 primary open-angle glaucoma patients treated with 0.5% timolol maleate (group 3) and 26 primary open-angle glaucoma patients treated with 0.5% betaxolol and 1% dipivefrin hydrochloride (group 4) were evaluated. Basal Schirmer's and tear break-up time tests were measured and ocular surface changes were determined by impression cytology. Impression cytology specimens of each group were graded and scored in the range 0-3 according to Nelson's method.

RESULTS

Patients in groups 2, 3 and 4 showed statistically significant fewer normal basal Schirmer's tests (wettability) and tear break-up time tests (P < 0.01). Also, the conjunctival impression cytology scores were significantly higher in groups 2, 3 and 4 than in group 1 (P < 0.01).

CONCLUSIONS

The conclusion was that it is possible that conjunctival surface and tear film function change after the long-term use of antiglaucoma medication.

The cardiovascular, pulmonary, and ocular hypotensive effects of 0.2% brimonidine

OBJECTIVE

To compare the cardiovascular, pulmonary, and ocular hypotensive effects of 0.2% brimonidine tartrate with those of 0.5% timolol maleate, 0.25% betaxolol suspension, and brimonidine vehicle.

DESIGN AND PATIENTS

A single-center, double-masked, randomized, crossover study of 24 young, healthy men.

INTERVENTIONS

Baseline heart rate, blood pressure, respiratory rate, and intraocular pressure were recorded at hour 0. At hour 2, heart rate, blood pressure, respiratory rate, and forced expiratory volume in 1 second were measured and a 15-minute treadmill test performed. Hour 0 measurements were repeated at hour 4. On four subsequent visits, we instilled one drop of a study medication into each eye after the baseline measurements at hour 0.

RESULTS

Timolol reduced resting (-5.3 to -6.5 beats/min, P < or = .004) and exercise-induced heart rate (-4.3 to -13.6 beats/min; P < or = .022) compared with brimonidine, betaxolol suspension, and brimonidine vehicle. At hour 4, brimonidine reduced resting systolic blood pressure compared with all other study medications (-5.2 to -7.3 mm Hg; P < or = .024). Timolol reduced systolic blood pressure during exercise and brimonidine reduced systolic blood pressure during recovery more than betaxolol suspension and brimonidine vehicle (-5.1 to -7.7 mm Hg; P < or = .033; and -5.4 to -6.0 mm Hg; P < or = .002, respectively). Mean respiratory rate and forced expiratory volume in 1 second were not significantly altered by any study medication. At hour 4, brimonidine lowered intraocular pressure as well as timolol and better than betaxolol suspension (-1.9 mm Hg; P < .001) or brimonidine vehicle (-1.8 mm Hg; P < .001).

CONCLUSIONS

The cardiopulmonary effects of 0.2% brimonidine were limited to a slight reduction in systolic blood pressure during recovery from exercise and at 4 hours after instillation. The ocular hypotensive effect of brimonidine was comparable to that of timolol and greater than that of betaxolol suspension in this patient population.

Retrobulbar arterial hemodynamic effects of betaxolol and timolol in normal-tension glaucoma

PURPOSE

beta-Adrenergic blocking drugs lower intraocular pressure. The question of whether these drugs also alter, either directly or indirectly, orbital hemodynamics is potentially of great importance for patients with normal-tension glaucoma who may have some degree of reversible vasospasm.

METHODS

We compared the effect of selective (betaxolol) and nonselective (timolol) beta-adrenergic blocking drugs on flow velocities (as determined by color Doppler imaging) in orbital vessels in 13 patients with normal-tension glaucoma (mean age, 62 +/- 3 years; mean intraocular pressure, 15 +/- 2 mm Hg). A one-month drug treatment double-masked crossover design, with a three-week washout before each drug, was used.

RESULTS

Neither drug changed peak systolic velocity in any of the four vessels studied (ophthalmic, nasal and temporal posterior ciliary, and central retinal arteries). Additionally, timolol did not alter end-diastolic velocity or resistance index (defined as [peak systolic velocity minus end-diastolic velocity] divided by peak systolic velocity) in any of the vessels measured. In contrast, betaxolol tended to increase end-diastolic velocity and to decrease resistance index: the four-vessel average end-diastolic velocity increased 30% (P = .08), and the four-vessel average resistance index decreased significantly (P = .04). These reductions in resistance index occurred despite that betaxolol, in contrast to timolol, did not significantly decrease intraocular pressure.

CONCLUSIONS

These results suggest that, in patients with normal-tension glaucoma, selective beta-adrenergic blockade (betaxolol) may have ocular vasorelaxant effects independent of any influence on intraocular pressure, whereas nonselective blockade (timolol) lowers intraocular pressure without apparently altering orbital hemodynamics.

A comparison of the safety and efficacy of twice daily brimonidine 0.2% versus betaxolol 0.25% in subjects with elevated intraocular pressure. The Brimonidine Study Group III

The safety and ocular hypotensive efficacy of twice-daily administration of brimonidine 0.2% solution or betaxolol 0.25% suspension were compared in subjects with open-angle glaucoma or ocular hypertension. A total of 206 adult patients were enrolled in a prospective, 3-month, multicentered, randomized, double-masked, parallel-group study. Both drugs significantly (p < 0.001) reduced peak and trough intraocular pressure (IOP) at every scheduled follow-up visit over the 3-month study. At peak, the overall mean decrease from baseline IOP was greater (p = 0.004) in the brimonidine-treated group (5.8 mm Hg) than in the betaxolol-treated group (3.8 mm Hg). At trough, the overall mean decrease from baseline (p < 0.001) was 3.9 mm Hg in the brimonidine-treated group and 3.2 mm Hg in the betaxolol-treated group. The IOP-lowering effect of brimonidine was sustained throughout the 3-month study period. Terminations from the study due to lack of efficacy included 2.9% (3/103) of patients in the brimonidine group and 4.2% (4/96) of those in the betaxolol group. The overall incidence of adverse events was similar in both treatment groups, with the only significant (p = 0.027) between-group difference being that ocular blurring was reported more often by patients receiving betaxolol suspension than by those receiving brimonidine treatment. Instillation of drug was reported to be comfortable (p = 0.036) by more brimonidine-treated patients than betaxolol-treated patients. Overall, brimonidine 0.2% solution was well-tolerated, safe and clinically and statistically more effective than betaxolol 0.25% suspension in lowering intraocular pressure in patients with open-angle glaucoma or ocular hypertension.

A double-masked, randomized, 1-year study comparing the corneal effects of dorzolamide, timolol, and betaxolol. Dorzolamide Corneal Effects Study Group

OBJECTIVE

To compare the long-term effects of dorzolamide hydrochloride (Trusopt, Merck and Co Inc, White-house Station, NJ), timolol maleate, and betaxolol hydrochloride on corneal endothelial cell density and corneal thickness.

METHODS

This 1-year multicenter study was conducted in 298 patients with ocular hypertension or open-angle glaucoma who had a baseline central corneal endothelial cell density greater than 1500 cells/mm2 and central corneal thickness less than 0.68 mm in each eye. Patients were randomized to 0.5% betaxolol twice daily, 0.5% timolol twice daily, or 2.0% dorzolamide 3 times daily. Specular microscopy and ultrasonic pachymetry of the central cornea was performed at baseline and 6 and 12 months following institution of therapy. Endothelial cell densities were determined by a single masked observer.

RESULTS

The mean percent changes from baseline for both outcome measures were similar in all 3 treatment groups at both 6 and 12 months. After 1 year of treatment, the mean percent loss in endothelial cell density from baseline was 3.6%, 4.5%, and 4.2% for the dorzolamide, timolol, and betaxolol groups, respectively. The mean percent change from baseline for corneal thickness was 0.47%, -0.25%, and 0.39% for the dorzolamide, timolol, and betaxolol groups, respectively.

CONCLUSIONS

Dorzolamide is equivalent to timolol and betaxolol in terms of the change in central endothelial cell density and thickness after 1 year of therapy. All 3 treatments exhibit good long-term corneal tolerability in patients with normal corneas at baseline.

A double-masked randomized comparison of the efficacy and safety of unoprostone with timolol and betaxolol in patients with primary open-angle glaucoma including pseudoexfoliation glaucoma or ocular hypertension. 6 month data

PURPOSE

A long-term comparison of the ocular hypotensive efficacy and safety of unoprostone isopropyl 0.15% twice daily with that of timolol maleate 0.5% twice daily and betaxolol HCl 0.5% twice daily.

DESIGN

This was a randomized, multicenter, double-masked, active-controlled 24-month clinical trial involving 27 centers in Europe and Israel.

METHODS

The study population was composed of patients with primary open-angle glaucoma (including pseudoexfoliation) or ocular hypertension. After washout of antiglaucoma medications, intraocular pressure (IOP) was measured at 0, + 2, + 8, and + 12 hours. Patients were randomized in a 2:1:1 ratio to unoprostone, timolol, or betaxolol. Patients returned for examinations at 2 and 6 weeks and 3 and 6 months.

RESULTS

556 patients were randomized. Each drug produced a clinically and statistically (P <.001) significant reduction from baseline in 12-hour diurnal IOP at month 6 (- 4.3 mm Hg, unoprostone; - 5.8 mm Hg, timolol; - 4.9 mm Hg, betaxolol). Differences in adjusted treatment means between unoprostone and timolol and unoprostone and betaxolol were 1.57 mm Hg (95% CI: 1.00, 2.13) and 0.53 mm Hg (95% CI: - 0.03, 1.09), respectively. Unoprostone was clinically equivalent to betaxolol but did not have as great an IOP-lowering effect as timolol. Discontinued for inadequate control of IOP were 7%, 1%, and 4% of the patients for unoprostone, timolol, and betaxolol, respectively. There were no changes of note in visual acuity, pupil size, cup-to-disk ratio, visual fields, or iris color. Changes in heart rate and blood pressure were small, with no clinically significant differences between groups.

CONCLUSIONS

Unoprostone provided a clinically significant IOP-lowering effect equivalent to betaxolol but not to timolol. The side effect profile of unoprostone appears to be comparable to other established IOP-lowering agents.

A comparative study of betaxolol and dorzolamide effect on ocular circulation in normal-tension glaucoma patients

OBJECTIVE

To determine whether dosages of a selective beta-blocking agent (betaxolol) and a topical carbonic anhydrase inhibitor (dorzolamide), sufficient to significantly lower intraocular pressure (IOP), have similar or disparate impact on the retinal and retrobulbar circulation.

DESIGN

Counterbalanced crossover, with open-label use of medications.

PARTICIPANTS

Nine persons with normal-tension glaucoma (NTG).

INTERVENTION

After a 3-week drug washout, NTG patients were studied after 1 month of treatment with either dorzolamide or betaxolol, with determinations of IOP and retinal and retrobulbar hemodynamics.

MAIN OUTCOME MEASURES

At baseline and after treatment with each drug, retinal arteriovenous passage time was determined by scanning laser ophthalmoscopy after fluorescein dye injection, and flow velocities in the central retinal and ophthalmic arteries were measured with color Doppler ultrasonography imaging.

RESULTS

Betaxolol and dorzolamide each lowered IOP significantly, with these changes apparent and maximal after 2 weeks (each P < 0.05). In contrast, dorzolamide (but not betaxolol) accelerated arteriovenous passage of fluorescein dye in the inferior temporal quadrant of the retina (P < 0.05). Neither drug affected arteriovenous passage in the superotemporal retina or any aspect of central retinal or ophthalmic artery flow velocity after either 2 or 4 weeks.

CONCLUSIONS

Although both dorzolamide and betaxolol are effective ocular hypotensive agents and their topical instillation leaves retrobulbar hemodynamics unaltered, dorzolamide alone accelerates inferotemporal retinal dye transit.

The efficacy of topical prophylactic antiglaucoma therapy in primary closed angle glaucoma in dogs: a multicenter clinical trial

The ability of either 0.5% betaxolol (1 drop topically, bid; n=31) or a combination of 0.25% demecarium bromide and a topical corticosteroid (gentamicin/betamethasone) (DB/GB; 1 drop of each topically, sid; n=55) to prevent glaucoma in the fellow eye of dogs with unilateral, primary closed angle glaucoma (PCAG) was investigated in a multicenter, open-label, clinical trial. Untreated control dogs (n=20) developed glaucoma significantly sooner (median, eight mos; p less than 0.001) than dogs treated either with DB/GB (median, 31 mos) or betaxolol (median, 30.7 mos). Although DB/GB and betaxolol equally delayed or prevented the onset of glaucoma in the second eye, a less frequent dosing schedule for DB/GB suggests demecarium bromide in combination with a topical corticosteroid may be preferable to betaxolol in preventing PCAG in dogs.

Alpha-1-noradrenergic neurotransmission, corticosterone, and behavioral depression

BACKGROUND

Impaired brain alpha-1 noradrenergic neurotransmission has been implicated in some of the symptoms of depressive illness but has been difficult to investigate experimentally because of the insensitivity of current animal models of depression. The present experiment addressed this problem by examining the effects of pharmacologic blockade and corticosteroid-induced desensitization of alpha-1 receptors on two newer, more sensitive models in mice: the inhibition of nest-leaving and the tail suspension tests (TST).

METHODS

Male mice were administered either prazosin, betaxolol, atipamezole, corticosterone, or repeated restraint stress prior to measurement of either nest-leaving or TST. General behavioral function was assessed in horizontal wire, swim, and latency to escape footshock tests.

RESULTS

Prazosin increased depressive behavior in the nest-leaving and TSTs, whereas corticosterone and restraint stress did so only in the more sensitive nest-leaving test. Betaxolol also reduced nest-leaving, suggestive of an alpha-1 beta-1 receptor synergy. The effects of these agents could not be attributed to hypotension, sedation, or general behavioral impairment.

CONCLUSIONS

The fact that a reduction in alpha-1 noradrenergic neurotransmission increases depressive behavior, coupled with the fact that this change can result from elevated corticosteroid secretion, provides further support for a role of this factor in depressive illness. As not all alpha-1 functions are reduced in depression, it is likely that only a subgroup or specific locality of alpha-1 receptors are affected.

Ion exchange resins for ophthalmic delivery

A new novel delivery system for ophthalmic drugs was developed using an antiglaucoma agent Betaxolol Hydrochloride as a model. The new delivery system involved both the binding and release of drug from ion exchange resin particles. Betaxolol was studied in-vitro via a release model analysis. The ocular comfort of Betaxolol was greatly enhanced by reducing the availability of free drug molecules in the precorneal tear film. The amount of resin concentration was selected to obtain optimum binding of the drug. The zeta potential of suspended particles was adjusted to produce flocculated suspension. Drug resin particles were then incorporated into the structured vehicle, containing Carbomer 934P as a polymer, to enhance the physical stability and ease of resuspendability of the product. This delivery system also optimized the bioavailability of Betaxolol, reducing the total drug concentration in half to 0.25% Betaxolol in 0.25% BETOPTIC S Ophthalmic Suspension as compared with 0.5% Betaxolol in BETOPTIC 0.5% Sterile Ophthalmic Solution dosage form. Increased comfort of 0.25% BETOPTIC S Ophthalmic Suspension, as well as its bioequivalency data in animal models (rabbits), was confirmed in actual clinical trials of the product 0.25% BETOPTIC S Ophthalmic Suspension. The 0.25% BETOPTIC S Ophthalmic Suspension product has been approved gamma FDA and is marketed in U. S. since February 1990. The 0.25% BETOPTIC S Ophthalmic Suspension formulation has an increased bioavailability (equivalent to BETOPTIC 0.5% Sterile Ophthalmic Solution at half the concentration of drug); and pharmaceutically, is an elegant suspension product which settles slowly providing uniform dosage and increased ocular comfort.

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.

Formulation influence on conjunctival penetration of four beta blockers in the pigmented rabbit: a comparison with corneal penetration

The objective of this study was to compare the influence of pH, tonicity, benzalkonium chloride, and EDTA on the conjunctival and corneal penetration of four beta blockers--atenolol, timolol, levobunolol, and betaxolol. Drug penetration was evaluated using the isolated pigmented rabbit conjunctiva and cornea in the modified Ussing chamber. The conjunctiva was more permeable than the cornea to all four beta blockers. Formulation changes caused larger changes in corneal than in conjunctival drug penetration, especially for the hydrophilic beta blockers, atenolol and timolol. Raising the solution pH to 8.4 caused the largest increase in corneal penetration for all drugs except atenolol. This increase was greater than that obtained by removing the corneal epithelium. The same formulation also increased conjunctival drug penetration, although to a lesser extent. In the case of timolol, the formulation changes evaluated brought about similar changes in its ocular and systemic absorption with good in vitro-in vivo correlations. The above findings indicate that in making formulation changes to maximize corneal drug penetration, it is necessary to evaluate possible changes in conjunctival drug penetration, hence systemic absorption. Moreover, because the conjunctiva plays an active role in the noncorneal route of ocular drug absorption, the relative contribution of the noncorneal to the corneal routes to ocular drug absorption may also be altered by formulation changes.

Ocular drug delivery using 20-kHz ultrasound

The cornea is a major pathway for drug delivery to diseased eye structures. We have investigated the application of 1-s bursts of 20-kHz ultrasound, at I(SAPA) of 14 W/cm(2) (I(SATA) of 2 W/cm(2)), for enhancement of corneal permeability to glaucoma drugs of different lipophilicity (atenolol, carteolol, timolol and betaxolol). The permeability of rabbit cornea increased by 2.6 times for atenolol, 2.8 for carteolol, 1.9 for timolol and 4.4 times for betaxolol (all p-values < 0.05), after 60 min of ultrasound (US) exposure in vitro. The differences between the treatment and control experiments were statistically significant after 10 to 30 min of US exposure for all four drugs. US application appeared to produce epithelial disorganization and structural changes in the corneal stroma. Further studies are needed to determine the optimal US parameters for a safe and effective treatment.

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.

Longterm effect of topical beta-blockers on intraocular pressure and visual field sensitivity in ocular hypertension and chronic open-angle glaucoma

In a prospective, randomized study, nineteen patients with ocular hypertension (n = 14) or chronic open-angle glaucoma (n = 5) were treated with either betaxolol 0.5% or timolol 0.5% in both eyes twice daily. Visual field sensitivity and intraocular pressure were assessed with the Octopus perimeter (program G1) and applanation tonometry, respectively, at 3, 6, 12, 24, 36, and 48 months during treatment. Four of the nineteen patients (two timolol-treated and two betaxolol-treated) were lost to follow-up after the 36-month examination. Whereas both drugs reduced the intraocular pressure, the decrease in the timolol-treated group was statistically more pronounced than in the betaxolol-treated group at month 3, 6, and 48 (p < 0.03). In both treatment groups, the visual field mean sensitivity (MS) index decreased slightly during the first six months of treatment, but remained so only in the timolol-treated group at all subsequent examinations. In the betaxolol-treated group, there was a statistically significant increase in MS at the 12, 24, 36, and 48 month visits (p < 0.01). These findings suggest that factors other than IOP alone may determine visual field outcome.

Effects of topical timolol (0.5%) and betaxolol (0.5%) on corneal sensitivity

There are conflicting reports on the propensity of topical beta blockers to produce corneal anaesthesia. We measured corneal sensitivity thresholds quantitatively for 10 minutes following the administration of one drop of topical timolol maleate (0.5%), betaxolol hydrochloride (0.5%), or saline in 30 eyes of 18 normal subjects in a randomised, double-masked study. Most subjects had insignificant changes in corneal sensitivity thresholds. We identified, however, a subgroup of four subjects (five eyes) that had a marked and prolonged increase of corneal sensitivity threshold (corneal anaesthesia) after timolol (three eyes) and betaxolol (two eyes). The group mean age of these 'responders' (49.0 years) was significantly greater (p less than 0.005) than that of the non-responders (35.0). We recommend periodic measurements of corneal sensitivity in older patients receiving topical timolol or betaxolol, especially when given in higher concentrations, to identify responders, who may be at risk of developing keratitis.

The acute effect of topical beta-adrenoreceptor blocking agents on retinal and optic nerve head circulation

PURPOSE

Topical beta-blockers are the most common treatment for ocular hypertension in glaucoma, but their ocular hemodynamic effects are not well known. We investigated the acute effects of betaxolol (beta-1 selective antagonist), levobunolol (non-selective antagonist with active polar metabolite), and timolol (non-selective antagonist) on retinal and superficial optic nerve head circulation.

METHODS

Intraocular pressure (IOP), heart rate, blood pressure, and retinal circulation were evaluated in 12 healthy subjects (6F/6M; mean age=24+/-2 years) before and two hours after instillation of each drug on separate occasions at least two weeks apart. Macular capillary blood velocity (MCBV), epipapillary blood velocities (EBV), arteriovenous passage (AVP) times, and arterial and venous diameters were measured by digital image analysis of scanning laser fluorescein angiograms.

RESULTS

All drugs significantly (p<0.05) reduced IOP. There was no significant effect on blood pressure or calculated ocular perfusion pressure. Only levobunolol significantly lowered heart rate (p<0.05). Each drug produced a significant (p<0.01) decrease in AVP time of approximately 25%. MCBV was significantly (p<0.01) increased by approximately 20% in all three conditions; each drug also produced significant (p<0.01) increases in EBV. Arterial and venous diameters remained unaffected.

CONCLUSION

All three drugs, despite different beta-adrenergic properties, increased blood velocities in retinal and epipapillary capillaries. These changes, occurring as they do in concert with decreased retinal arteriovenous passage time at constant retinal arterial and venous diameter, may indicate improved retinal perfusion after drug treatment. Improved circulation, if it indeed occurs, in tandem with reduced IOP, might explain in part the beneficial effect of beta-adrenoreceptor blocking agents in glaucomatous patients.

The comparative cardiovascular, pulmonary, ocular blood flow, and ocular hypotensive effects of topical travoprost, bimatoprost, brimonidine, and betaxolol

OBJECTIVE

This study evaluated systemic and ocular acute safety and intraocular pressure (IOP)-lowering efficacy of travoprost 0.004% and bimatoprost 0.03%, compared to brimonidine 0.2% and betaxolol 0.25% in healthy subjects.

PATIENTS AND METHOD

Nineteen (19) young men, ages between 24 and 42, were enrolled in a single-center, institutional randomized, double-masked, crossover clinical trial. Baseline IOP, heart rate, blood pressure, and respiratory rate were recorded at hour 0. At minute 30, heart rate, blood pressure, respiratory rate, and spirometry were measured. At hour 1, color Doppler imaging of retrobulbar vessels was performed. At hour 2, heart rate, blood pressure, and respiratory rate were measured; spirometry and a 15-minute treadmill test were performed. The same protocol was applied after one drop of a study medication was instilled into each eye on four subsequent visits at 5-day intervals.

RESULTS

Travoprost and bimatoprost did not cause significant reductions in systolic blood pressure during exercise and recovery. The mean respiratory rate and forced expiratory volume in 1 second were not significantly altered by any study medication. Travoprost reduced the resistive index and increased blood velocities in the ophthalmic artery and its branches. Bimatoprost caused a significant increase in end diastolic velocity of the ophthalmic artery. At hour 6, all medications reduced IOP significantly (p < 0.05). The most frequent ocular side effect of travoprost and bimatoprost was conjunctival hyperemia.

CONCLUSION

Travoprost and bimatoprost were found to be systemically safe and caused an increase in blood-flow velocities of the retrobulbar vessels after a single-dose application. Their ocular hypotensive effect was comparable to that of brimonidine and greater than that of betaxolol in healthy subjects.

Improved lung function tests on changing from topical timolol: non-selective beta-blockade impairs lung function tests in elderly patients

Fifty-two elderly glaucomatous patients, without a history of asthma or obstructive airways disease, who were using topical timolol for control of intraocular pressure were recruited. Their topical therapy was changed to either betaxolol or pilocarpine. The change was associated with improvement in mean peak flow from 278 l/min to 328 l/min (t = 5.73, p < 0.001), mean FEV1 from 1.66 l to 1.85 l (t = 7.09, p < 0.001) and mean FVC from 2.40 l to 2.64 l (t = 5.07, p < 0.001). Change to either betaxolol or pilocarpine was associated with improved lung function tests. Lung function tests in a control group of 20 showed no significant changes. Both drugs maintained control of intraocular pressure but betaxolol had fewer ocular side effects.

Compliance, clinical outcome, and quality of life of patients with stable angina pectoris receiving once-daily betaxolol versus twice daily metoprolol: a randomized controlled trial

Background

A randomized, controlled trial was conducted in an outpatient setting to examine the effect of beta-blocker dosing frequency on patient compliance, clinical outcome, and health-related quality of life in patients with stable angina pectoris.

Methods

One hundred and twelve beta-blockers-naive outpatients with stable angina pectoris were randomized to receive betaxolol, 20 mg once daily or metoprolol tartrate, 50 mg twice daily for 8 weeks. The principal outcome measure was overall compliance measured electronically, whereas secondary outcome measures were drug effectiveness and health-related quality of life.

Results

The overall compliance was 86.5 ± 21.3% in the betaxolol group versus 76.1 ± 26.3% in the metoprolol group (p < 0.01), and the correct number of doses was taken on 84.4 ± 21.6% and 64.0 ± 31.7% of treatment days, respectively (p < 0.0001). The percentage of missed doses was 14.5 ± 21.5% in the once-daily group and 24.8 ± 26.4% in the twice-daily group (p < 0.01). The percentage of doses taken in the correct time window (58.6% vs 42.0%, p = 0.01), correct interdose intervals (77.4% v 53.1%, p < 0.0001), and therapeutic coverage (85.6% vs 73.7%, p < 0.001) were significantly higher in the once-daily group. Both studied drugs had similar antianginal effectiveness. Health-related quality of life improved in both groups, but this increase was more pronounced in the betaxolol arm in some dimensions.

Conclusions

The study demonstrates that patient compliance with once-daily betaxolol is significantly better than with twice daily metoprolol. Similarly, this treatment provides better quality of life. These results demonstrate possible therapeutic advantages of once-daily over twice-daily beta-blockers in the treatment of stable angina pectoris.

Changes in depressive status associated with topical beta-blockers

Depression and sexual dysfunction have been related to side effects of topical beta-blockers. We performed a preliminary study in order to determine any difference between a non selective beta-blocker (timolol) and a selective beta-blocker (betaxolol) regarding CNS side effects. Eight glaucomatous patients chronically treated with timolol 0.5%/12h, suffering from depression diagnosed through DMS-III-R criteria, were included in the study. During the six-month follow up, depression was quantified through the Beck and Zung-Conde scales every two months. In a double blind cross-over study with control group, the patients under timolol treatment presented higher depression values measured through the Beck and the Zung-Conde scales (p < 0.001 vs control). These results suggest that betaxolol could be less of a depression-inducer than timolol in predisposed patients.

Effect of topical betaxolol on tissue circulation in the human optic nerve head

There have been no reports to date on long-term betaxolol instillation effects on the human optic nerve head (ONH) tissue circulation. The purpose of this study was to study the effect of topical 0.5% betaxolol on tissue blood velocity in the human ONH. Using a laser-speckle tissue blood flow analyzer, normalized blur (NB; a quantitative index of tissue blood velocity) was measured every 0.125 seconds at a temporal ONH site free of visible surface vessels. Measurements were averaged for 3 cardiac cycles (NB(ONH)). For baseline comparison (day 0), recordings of bilateral NB(ONH) and intraocular pressure (IOP), blood pressure (BP) and pulse rate (PR) were recorded in healthy volunteers before, and 2, 4.5, and 7 hr after, instillation of 30 microL of betaxolol vehicle, and again on day 21; IOP was also recorded on days 7 and 14. On day 1 (the day after baseline measurements), and twice daily for 3 weeks, 30 microL of 0.5% betaxolol into one eye and 30 microL vehicle was instilled into the other in a double-blind study. Measurements as on day 0 were again recorded on day 21; IOP was also recorded on days 7 and 14. During baseline recordings, no significant changes were noted in any parameters. After administration of topical betaxolol, IOP was significantly reduced, bilaterally, with greater reduction in the betaxolol-treated eyes on day 21. Also on day 21, the NB(ONH) of the betaxolol-treated eyes was significantly higher 4.5 hr after instillation than that of the comparable baseline recording (p = 0.035 with Bonferroni's correction); BP, PR, and NB(ONH) in the eye which received only the vehicle showed little change. Tissue blood velocity in the human ONH was increased at least temporarily by instillation of topical betaxolol twice daily for 3 weeks. Although the obtained increase is small and may be clinically insignificant, the potential of betaxolol that can affect the ONH tissue circulation in humans after 21 days of instillation is thought to deserve further investigation.