Comparison of the Effects of Topical Levobunolol and Timolol Solution on the Human Ocular Surface

PURPOSE

To compare the effects of levobunolol hydrochloride and timolol maleate on tear volume, precorneal tear film stability, and corneal epithelial barrier function in normal human eyes.

SUBJECTS AND METHODS

The study population consisted of 14 healthy volunteers. To obtain pretreatment baseline values, we determined the radius of the tear meniscus (RTM) by meniscometry; the noninvasive breakup time (NIBUT) of the precorneal tear film with a tear specular microscope; and corneal fluorescein uptake with a fluorophotometer. Levobunolol hydrochloride (0.5%) or timolol maleate solution (0.5%) was instilled twice daily for 4 weeks into 1 eye; the contralateral eye was treated with the other topical drug twice daily for the same period. At the end of the study period, the same tests were performed, and the pre- and posttreatment results were compared.

RESULTS

Timolol solution did, and levobunolol did not, significantly reduce NIBUT from the baseline values. RTM was significantly decreased by treatment with either timolol or levobunolol solution. Corneal fluorescein uptake was not significantly changed, although it was higher after treatment with both topical drugs.

CONCLUSIONS

Four-week treatment with timolol solution resulted in significant instability of the precorneal tear film. Both timolol and levobunolol solution significantly decreased tear volume on the ocular surface. These results indicate that levobunolol solution applied twice daily has equal effects on the tear volume and corneal epithelial barrier function as does timolol solution applied twice daily and that it affects precorneal tear film stability less than timolol solution.

A comparison of the efficacy and tolerability of 0.5% timolol maleate ophthalmic gel-forming solution QD and 0.5% levobunolol hydrochloride BID in patients with ocular hypertension or open-angle glaucoma

The purpose of this study was to compare the ocular hypotensive efficacy and tolerability of 0.5% timolol maleate ophthalmic gel-forming solution (timolol gel) and 0.5% levobunolol hydrochloride (levobunolol). This was a randomized, double-masked, multi-center, active-controlled, 2-period, crossover study. After a 3-week, single-masked placebo run-in phase, patients with ocular hypertension or open-angle glaucoma and an intraocular pressure (IOP) > or = 22 mmHg were randomized to receive timolol gel QD or levobunolol BID for 6 weeks followed by a 3-week, placebo washout period. Patients were then crossed over to the alternate treatment for 6 weeks. IOP and heart rate (HR) were measured at 3 and 6 weeks after the start of therapy with either timolol gel or levobunolol. Of 133 patients randomized, 116 received both treatments. Timolol gel QD was comparable to levobunolol BID in reducing trough and peak IOP. At trough, HR was marginally increased with timolol gel and was decreased with levobunolol (p = < 0.001). At peak, HR was decreased with both treatments, but the decrease was significantly less with timolol gel than with levobunolol (p = 0.049). Significantly more patients experienced at least one adverse event (p = 0.024), adverse events related to special senses (p = 0.002), and burning and stinging (p < 0.001) with levobunolol compared to timolol gel. The study demonstrates that timolol gel QD has IOP-lowering effects comparable to those of levobunolol BID with fewer adverse experiences and less effect on HR.

Allergic reactions to brimonidine in patients treated for glaucoma

BACKGROUND

Allergic reactions to ophthalmic drugs have not been studied extensively in ophthalmology. We performed a study to estimate the incidence of allergy to brimonidine in patients treated for glaucoma.

METHODS

We identified all patients in a private glaucoma practice who started therapy with brimonidine between Mar. 19, 1998, and Aug. 14, 1999. We recorded the patient's diagnosis, age, sex, concomitant glaucoma medication, previous allergy to glaucoma medication and allergy to brimonidine. Allergy was defined as allergic contact dermatoconjunctivitis or follicular conjunctivitis.

RESULTS

Of the 140 patients identified, 36 (25.7%) had had an allergic reaction to brimonidine. Contact dermatoconjunctivitis was noted in 19 patients (52.8%) and follicular conjunctivitis in 18 (50.0%). The rate of development of those two manifestations was linear and almost parallel throughout the study period. In logistic regression analysis previous allergy to a topically given antiglaucoma medication (t = -5.13) and concurrent use of levobunolol (t = 3.46) were retained as the most probable predictor variables of allergy to brimonidine. Life-table analysis showed a fairly linear curve, with no peak in allergy rate. Allergic reactions occurred throughout the year, with a small peak in March.

INTERPRETATION

We found a rate of allergy to brimonidine of 25.7%. Concomitant levobunolol use and allergy to another glaucoma medication were associated with a higher allergy rate.

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.

Efficacy and tolerability of 0.5% timolol maleate ophthalmic gel-forming solution QD compared with 0.5% levobunolol hydrochloride BID in patients with open-angle glaucoma or ocular hypertension

We compared the efficacy of timolol maleate ophthalmic gel-forming solution 0.5% QD with that of levobunolol hydrochloride 0.5% BID, as measured by change in intraocular pressure (IOP), effect on heart rate, and ocular tolerability. The study had a positive-controlled, double-masked, randomized, multicenter, 12-week, two-period (6 weeks each), crossover design. One hundred fifty-two patients with open-angle glaucoma or ocular hypertension were randomized to receive either timolol maleate gel-forming solution QD or levobunolol BID for 6 weeks, followed by a crossover to the alternate treatment. IOP and heart rate were measured at morning trough and peak during weeks 3, 6, 9, and 12. Timolol maleate gel-forming solution QD was comparable to levobunolol BID in reducing IOP at peak and trough. Although the effects on peak heart rate were similar between the two medications, the effect on trough heart rate of timolol maleate gel-forming solution QD was significantly less than that of levobunolol BID (P = 0.001). The incidence of ocular burning and stinging was comparable between the two treatments. Patients experienced significantly more blurred vision when using timolol maleate gel-forming solution than when using levobunolol (P = 0.013). Overall, more patients experienced at least one adverse event when using timolol maleate gel-forming solution. Timolol maleate gel-forming solution QD is as efficacious in reducing IOP as levobunolol BID.

[Contact allergy to eyedrops containing beta-blockers]

In six patients (4 women aged 80, 62, 43 and 52 years and 2 men aged 58 and 51 years), who used eyedrops containing beta-blockers for the treatment of glaucoma, allergic contact dermatitis of the eyelids was diagnosed. Three were allergic to metipranolol, 2 to levobunolol and 1 to timolol. In literature, less than 50 cases of hypersensitivity to beta-blockers in eye medication have been reported. There are, however, reasons to assume that sensitization is more frequent: (a) not all patients are referred by the ophthalmologist to the dermatologist; (b) false-negative reactions to patch tests with the commercial preparations and with beta-blockers are not infrequent; (c) they are not routinely tested because beta-blockers are difficult to obtain in pure form; (d) cross-reactions with other beta-blockers are infrequent, and changing to another preparation therefore usually solves the clinical problem. Nevertheless it is advisable to test a battery of beta-blockers (befunolol, levobunolol, metipranolol, timolol) in allergic patients. A test preparation of 2% in water or 3%-10% in petrolatum may be suitable. Control testing in non-exposed individuals is necessary to exclude irritation reactions.

Adverse drugs reactions associated with glaucoma medications

We undertook a non-concurrent prospective study of 191 Puerto Rican patients from August 1993 to April 1994. All patients had open angle glaucoma (OAG) (age ranged from 50 to 80 yrs; mean = 65 yrs). Patient's symptomatology associated to side effects of their glaucoma medicadons was reviewed. Incidence percent of ocular and/or systemic side effects per medication were: levobunolol 45.0%; betaxolol 42.0%; timolol 27.3%; pilocarpine 100%; dipivefrin 14.0%; and acetazolamide 250 mg 64.1%. Incidence percent of ocular and/or systemic side effects of topical beta-blockers used with concomittant medications were determined. Ocular side effects were more frequent in patients using levobunolol 44.2% than in those patients using betaxolol 42.0%, 8.5% of patients using levobunolol did report systemic side effects. No systemic side effects were reported by patients using betaxolol. Ocular side effects in patients using pilocarpine were frequent (100%); whereas the frequency of systemic side effects was low (6.1%). Systemic side effects were common in patients using carbonic anhydrase inhibitors. These results suggest that non-selective and cardio-selective topical Beta-blockers, differ in their ocular or systemic side effects.

The safety of topical beta-blockers in glaucoma treatment

While adverse effects are uncommon in patients who are otherwise fit and well, doctors should be aware of the implications of the systemic effects of these drugs, particularly the non-selective types, and particularly in the elderly.

Lichen planus associated with topical beta-blocker therapy

PURPOSE

We studied two clinical cases that demonstrated an association between topical beta-blocker therapy and lichen planus.

METHODS

Two patients developed skin lesions while on topical beta-blocker therapy for open-angle glaucoma. They underwent skin biopsies to determine the origin of the lesions. They were subsequently treated and followed up clinically.

RESULTS

Skin biopsy specimens from each patient demonstrated infiltrates consistent with a lichenoid drug reaction. The symptoms resolved after discontinuation of the topical beta-blocker therapy. Neither patient developed a recurrence.

CONCLUSION

We suggest that lichen planus is a possible side effect of topical beta-blocker therapy.

A comparison of the ocular hypotensive efficacy and systemic safety of 0.5% levobunolol and 2% carteolol

In a 3-month, double-masked, randomized clinical trial, the ocular hypotensive efficacy and systemic safety of 0.5% levobunolol and 2% carteolol were compared in 59 patients with open-angle glaucoma or ocular hypertension. The overall mean decrease in intraocular pressure was 7.3 mm Hg (27.4%) in the 0.5% levobunolol group and 4.1 mm Hg (14.8%) in the carteolol group. This difference was statistically significant (p = 0.0004). Changes in visual field and cup-disk ratios were few and similar between the groups. Effects on mean heart rate were noted in both treatment groups. The mean decrease in heart rate in the carteolol group was greater (-8.4 beats/min) than in the levobunolol group (-3.1 beats/min). This difference had marginal statistical significance (p = 0.059). We conclude that 0.5% levobunolol and 2% carteolol administered twice daily differ in lowering intraocular pressure as well as in their effects on heart rate.

A comparison of the ocular tolerability of a single dose of timolol and levobunolol in healthy normotensive volunteers

Subject acceptance of a single dose of timolol and levobunolol was compared in a three-center, double-masked, randomized, crossover study in healthy normal subjects. We tested 115 subjects who received the medications OU, in a random order, separated by a washout period of three to seven days. At the end of the administration, the subjects were asked to report any symptoms and were monitored by ophthalmologic examination. Those receiving levobunolol reported a two- to threefold higher frequency of symptoms than did those receiving timolol (P = .0002, by Mainland-Gart chi-square test). Thirty-five subjects (30.4%) treated with levobunolol complained of burning versus 14 (12.2%) receiving timolol (P = .0021). Similar results were obtained in regard to stinging (31 versus 10 subjects; P = .0011). The duration of these symptoms did not differ between the two groups (P > .05). Timolol induced considerably less burning and stinging on day 1 compared with levobunolol, using a visual analog scale over time (P = .0004). Seventy-nine percent of those stating a preference chose timolol (P < 3 x 10(-9).

[Hypersensitivity to levobunolol]

A case is described in which, following local application of glaucoma eye drops containing Levobunolol, a recurring allergic contact eczema with periocular localisation occurred. In the course of the epicutaneous allergy testing a positive reaction (crescendo-type) could be clearly demonstrated experimentally against both the eye drops and their active ingredient, levobunolol-hydrochloride, a beta-blocker (beta-sympatholyticum) out of the class of the aryloxypropylamines.

Effect of varying drop size on the efficacy and safety of a topical beta blocker

We studied the effects on efficacy and safety of varying the drop size of a topical solution of levobunolol 0.5%. In a double-masked, crossover acute study, we administered a single drop of either 35 microL of vehicle, or 20, 35, or 50 microL of levobunolol one hour before the subjects began a ten-minute treadmill challenge electrocardiogram. After exercise the mean heart rate was 111 beats per minute (bpm) in the vehicle group and 102 to 103 bpm in the three levobunolol groups, which were significantly different from the control group but not from each other. In a randomized double-masked, parallel, chronic study, 117 patients with elevated intraocular pressure (IOP) instilled one of the three drop sizes of levobunolol twice daily for three months. Mean decreases in IOP ranged from 5.1 to 6.0 mmHg in the three groups, not significantly different from each other in mean IOP, heart rate, or blood pressure. We conclude that drop size in the range tested had no clinically significant effect on either efficacy or safety of a beta blocker such as levobunolol.

Comparison of a noncardioselective beta-adrenoceptor blocker and a cardioselective blocker in reducing aqueous flow in humans

In a double-masked crossover study, the dose-response relationship for aqueous flow was determined for four concentrations of betaxolol hydrochloride and levobunolol hydrochloride in 19 normal subjects. One eye of each subject received every concentration of both drugs. Each concentration was administered once daily for 1 week. The fellow eye received a placebo. Aqueous flow was measured for several hours on the last day of administration of each concentration beginning immediately after drug administration. For levobunolol, the mean decrease in aqueous flow compared with baseline was 8% after 1 week's treatment with 0.017% levobunolol, 15% after treatment with 0.05%, 20% after treatment with 0.167%, and 32% after treatment with 0.5%. For betaxolol, the mean decrease in aqueous flow compared with baseline was 3% after 1 week's treatment with 0.017% betaxolol, 12% after treatment with 0.05%, 18% after treatment with 0.167%, and 17% after treatment with 0.5%. Levobunolol-treated eyes but not betaxolol-treated eyes showed a significant drug effect 1 week after discontinuing the drug therapy. The relative potency of the noncardioselective drug was greater than that of the beta 1-cardioselective drug, but the difference in potency was much less than would be expected solely based on their relative affinity for beta 2-receptors in other species and tissues.

Efficacy and safety of once-daily levobunolol for glaucoma therapy

We studied the ocular hypotensive efficacy and safety of 0.5% levobunolol hydrochloride and 0.5% timolol maleate administered topically once daily for 3 months in 91 patients (46 in the levobunolol group and 45 in the timolol group) with primary or secondary open-angle glaucoma or ocular hypertension. In this randomized double-masked parallel clinical study, intraocular pressure (IOP) was successfully controlled in 78% of the patients who received levobunolol and 89% of those who received timolol. The overall mean decrease in IOP was 5.6 mm Hg (decrease of 23%) in the levobunolol group and 6.7 mm Hg (26%) in the timolol group, a nonsignificant difference. In both groups the overall mean IOP during treatment was significantly lower than the pretreatment value (p less than 0.001). For both treatment groups changes in heart rate and blood pressure were minimal. We conclude that both 0.5% levobunolol and 0.5% timolol administered once daily are effective and safe in lowering IOP in most patients with ocular hypertension or open-angle glaucoma.

A combination of levobunolol and dipivefrin for the treatment of glaucoma

This double-masked prospective study compared the ocular hypotensive efficacy and the safety of 0.5% and 1% levobunolol hydrochloride with 0.5% timolol maleate when each was administered topically twice daily in combination with 0.1% dipivefrin hydrochloride. Forty-three patients whose intraocular pressure was previously controlled by concomitant treatment with timolol and dipivefrin were randomly assigned to receive 0.5% or 1% levobunolol and 0.1% dipivefrin, or to continue to receive 0.5% timolol and 0.1% dipivefrin for three months. In the groups receiving levobunolol and dipivefrin concurrently, continued intraocular pressure control was achieved equal to that attained with timolol and dipivefrin before study entry. We concluded that concomitant treatment with levobunolol and dipivefrin is equal in both efficacy and safety to concomitant treatment with timolol and dipivefrin.

Efficacy of twice-daily levobunolol in the treatment of elevated intraocular pressure

The efficacy of twice-daily treatment with 0.5% levobunolol hydrochloride was compared with that of 0.5% timolol maleate in 27 patients with open-angle glaucoma or ocular hypertension in a double-blind randomized trial. At all follow-up visits the patients in both groups had significantly decreased intraocular pressure (p less than 0.05); there was no significant difference between the groups. Levobunolol produced significant decreases in mean heart rate (p less than 0.05). One patient with an undisclosed history of childhood asthma experienced bronchospasm related to an acute upper respiratory tract infection while receiving levobunolol. Neither drug caused any significant ocular problems. The results show a clear ocular hypotensive effect with twice-daily 0.5% levobunolol.

A multicenter evaluation of levobunolol (Vistagan) in Germany

We evaluated the efficacy and safety of 0.5% levobunolol HC1 (Vistagan) in 2,041 glaucoma patients at 143 sites in the Federal Republic of Germany. This study was a 3-month, open-label, noncomparative trial of levobunolol administered twice daily. Eighty-five percent of the patients completed the study period with well-controlled intraocular pressure (IOP). Treatment was discontinued in the remaining 15%: 7% for adverse reactions, 1% for lack of drug efficacy, and 7% for reasons unrelated to the study treatment. Efficacy, ocular drug tolerance, and systemic safety were judged as good to very good in approximately 80% of the patients. This large, postapproval study confirms previous findings of several well-controlled clinical trials indicating that levobunolol is an effective drug for the treatment of elevated IOP and is safe and comfortable for most patients.

Betaxolol and levobunolol: new beta-blocking antiglaucoma agents

The Food and Drug Administration has recently approved the use of two new ophthalmic beta-adrenergic antagonistic agents: betaxolol hydrochloride (Betoptic) and levobunolol hydrochloride (Betagan). This paper reviews the history, pharmacologic properties, clinical efficacy and potential side effects of this expanding class of antiglaucoma medication.

Plasma levobunolol levels following topical administration with reference to systemic side effects

We determined the plasma level of levobunolol in normal volunteers after a single topical instillation of 0.5 or 1% levobunolol in both eyes, and after twice-daily instillations for 1 week. Levobunolol levels were detected within 1 h following acute instillation. During the study, mean plasma levels ranged from 0.1 to 0.3 ng/ml for the 0.5% group and 0.3 to 0.6 ng/ml for the 1% group. The highest individual plasma level was 1.2 ng/ml, which occurred in 1 patient receiving 1% levobunolol. After 1 week of twice-daily instillation mean plasma levels were similar to those observed after acute instillation. Minimal cardiovascular changes were observed in the 0.5% group while decreases in heart rate and systolic blood pressure were observed in the 1% treatment group.

Glaucoma treatment with once-daily levobunolol

Although twice-daily instillation of topical beta-blockers is the standard regimen for treatment of increased intraocular pressure, once-daily therapy might improve patient compliance and provide greater safety. In a three-month, double-masked clinical trial, 92 patients with open-angle glaucoma or ocular hypertension received levobunolol 0.5% or 1% or timolol 0.5% once daily, in both eyes. Overall mean decreases in intraocular pressure were significantly greater in the groups treated with levobunolol than in the group treated with timolol. Intraocular pressure decreases averaged 7.0 mm Hg with levobunolol 0.5%, 6.5 mm Hg with levobunolol 1%, and 4.5 mm Hg with timolol. The intraocular pressures of 72% (18 of 25 patients) of those treated with levobunolol 0.5%, 79% (22 of 28 patients) of those treated with levobunolol 1%, and 64% (16 of 25 patients) of those treated with timolol were successfully controlled during the study. Heart rate and blood pressure decreases were minimal with both levobunolol and timolol. Study results indicated that once-daily treatment with levobunolol and, to a lesser extent, timolol is sufficient to control intraocular pressure successfully and safely.

[Local subjective tolerance of levobunolol and metipranolol in a double-blind comparative study in patients with increased intraocular pressure]

We evaluated the ocular comfort of 0.5% levobunolol hydrochloride and 0.6% metipranolol hydrochloride ophthalmic solutions in a randomized, double-masked, paired-comparison clinical trial. The drugs were given twice daily for 7 days to 16 patients with open-angle glaucoma or ocular hypertension. Patients rated comfort in terms of the severity of burning and/or stinging. For both drugs, the severity rating of ocular discomfort was low, averaging between 1 and 2 on a scale of 0-10. At initial and follow-up visits, the mean severity rating of burning or stinging with metipranolol was 2, slightly greater than the mean score of 1 with levobunolol. At 55% (26 of 47) of the patient visits, the patients rated levobunolol as more comfortable than metipranolol. Metipranolol (Betamann; Mann) was rated as more comfortable than levobunolol at only 9% (4 of 47) of the patient visits. The duration of burning and stinging was also rated as longer lasting with metipranolol treatment than with levobunolol (Vistagan; Pharma-Allergan) treatment. Although little ocular discomfort was reported for either drug, the majority of the patients tested rated levobunolol the more comfortable of the two drugs.

[Pressure lowering effect and side effects of 0.5% and 1.0% levobunolol eyedrops, compared with 0.5% timolol eyedrops in patients with open-angle glaucoma]

Fifty patients with open-angle glaucoma were treated twice daily for one year with topical 0.5% levobunolol, 1% levobunolol, or 0.5% timolol. Both concentrations of levobunolol were as effective as timolol in reducing intraocular pressure over the one-year period. At the concentrations tested, levobunolol and timolol decreased heart rate to a similar extent, suggesting that systemic absorption occurred after topical instillation. In all three treatment groups, clinically insignificant changes in blood pressure were observed sporadically throughout the one-year period. Very few clinically significant toxic ocular reactions were observed.

Levobunolol. A beta-adrenoceptor antagonist effective in the long-term treatment of glaucoma. The Levobunolol Study Group (Appended)

We compared the ocular-hypotensive efficacy and systemic and ocular safety of an ophthalmic solution of levobunolol (0.5% and 1%) twice daily, with timolol (0.5%) twice daily in a long-term double-masked study of 391 patients with open-angle glaucoma or ocular hypertension. Patients received the test medication in both eyes for up to two years. Over the two-year period, both concentrations of levobunolol reduced mean IOP by 27% (range, -6 to -8 mmHg). This ocular-hypotensive effect was sustained throughout the study and was similar to that produced by timolol. Slight decreases in mean heart rate and blood pressure were observed. No unexpected adverse ocular or systemic reactions were reported. The results of these studies indicate that levobunolol is an effective therapy for the long-term treatment of glaucoma.