A Cross-Over Trial Comparing Once Daily Levobunolol with Once and twice Daily Timolol

Effects of timolol maleate, levobunolol and apraclonidine on intraocular pressure, pupil size, blood pressure and heart rate in beagles

ABSTRACT The aim of this study was to evaluate changes in intraocular pressure (IOP), pupil size (PS), blood pressure (BP), heart rate (HR), and ECG variables (Pms wave PmV, PR interval, QRS complex, RMV wave and QT intervals) over time during the instillation of 0.5% timolol, 0.5% levobunolol and 0.5% apraclonidine in clinically normal dogs. Ten adult beagles were used. Baseline values were measured at 8a.m., 2p.m. and 8p.m., for three consecutive days. A waiting period of 10 days between the administrations of each drug was established. For 15 consecutive days, the drug being tested was instilled in one eye of each dog twice a day (7a.m. and 7p.m.). The parameters were evaluated at the aforementioned times on days 3, 6, 9, 12 and 15. Data were statistically compared using the Bonferroni test and one-way repeated measures analysis of variance (P<0.05). The Pearson test was used to evaluate any correlation between QT interval, HR and BP. The tested drugs did not find a decrease in IOP. A significant decreased in PS was observed in almost all dogs following levobunolol administration, relative to the control eye. A significant decrease in HR was observed on day 3 following levobunolol treatment, while apraclonidine induced an increase on day 15. Blood pressure was reduced in all measurement time points following apraclonidine treatment. A negative correlation between QT interval and HR was only observed in dogs treated with timolol. In conclusion, levobunolol was the only drug that induced significant alterations in PS. Apraclonidine was the only drug that induced systemic hypotension. Timolol was the only drug to that induced a negative correlation between QT and HR.

Interventions for improving adherence to ocular hypotensive therapy

BACKGROUND

Poor adherence to therapy is a significant healthcare issue, particularly in patients with chronic disease such as open-angle glaucoma. Treatment failure may necessitate unwarranted changes of medications, increased healthcare expenditure and risk to the patient if surgical intervention is required. Simplifying eye drop regimes, providing adequate information, teaching drop instillation technique and ongoing support according to the patient need may have a positive effect on improving adherence.

OBJECTIVES

To summarise the effects of interventions for improving adherence to ocular hypotensive therapy in people with ocular hypertension (OHT) or glaucoma.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 6), MEDLINE (June 1946 to June 2012), EMBASE (June 1980 to June 2012), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (June 1937 to June 2012), PsycINFO (1806 to June 2012), PsycEXTRA (1908 to June 2012), Web of Science (1970 to June 2012), ZETOC (1993 to June 2012), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 26 June 2012. We did not search the National Research Register (NNR) as this resource has now been now archived. We contacted pharmaceutical manufacturers to request unpublished data and searched conference proceedings for the Association for Research in Vision and Ophthalmology (ARVO), and the Annual Congress for the Royal College of Ophthalmologists (RCO).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs that compared interventions to improve adherence to ocular hypotensive therapy for patients with OHT or glaucoma.

DATA COLLECTION AND ANALYSIS

At least two authors independently assessed the search results for eligibility and extracted data for included trials onto specifically designed forms. We did not pool data due to clinical and methodological heterogeneity.

MAIN RESULTS

Sixteen trials (1565 participants) met the inclusion criteria. Seven studies investigated some form of patient education. In six of these studies this education was combined with other behavioural change interventions including tailoring daily routines to promote adherence to eye drops. Eight studies compared different drug regimens (one of these trials also compared open and masked monitoring) and one study investigated a reminder device. The studies were of variable quality and some were at considerable risk of bias; in general, the length of follow-up was short at less than six months with only two studies following up to 12 months. Different interventions and outcomes were reported and so it was not possible to produce an overall estimate of effect. There was some evidence from three studies that education combined with personalised interventions, that is, more complex interventions, improved adherence to ocular hypotensive therapy. There was less information on other outcomes such as persistence and intraocular pressure, and no information on visual field defects, quality of life and cost. There was weak evidence as to whether people on simpler drug regimens were more likely to adhere and persist with their ocular hypotensive therapy. A particular problem was the interpretation of cross-over studies, which in general were not reported correctly. One study investigated a reminder device and monitoring but the study was small and inconclusive.

AUTHORS' CONCLUSIONS

Although complex interventions consisting of patient education combined with personalised behavioural change interventions, including tailoring daily routines to promote adherence to eye drops, may improve adherence to glaucoma medication, overall there is insufficient evidence to recommend a particular intervention. The interventions varied between studies and none of the included studies reported on the cost of the intervention. Simplified drug regimens also could be of benefit but again the current published studies do not provide conclusive evidence. Future studies should follow up for at least one year, and could benefit from standardised outcomes.

Interventions for improving adherence to ocular hypotensive therapy

BACKGROUND

Poor adherence to therapy is a significant healthcare issue, particularly in patients with chronic disease such as open angle glaucoma. Treatment failure may necessitate unwarranted changes of medications, increased healthcare expenditure and risk to the patient if surgical intervention is required. Simplifying eye drop regimes, providing adequate information and ongoing support according to patient need, may have a positive effect on improving adherence.

OBJECTIVES

To summarise the effects of interventions for improving adherence to ocular hypotensive therapy in people with ocular hypertension (OHT) or glaucoma.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, CINAHL, PsycINFO, Web of Science, ZETOC and OpenSIGLE. In addition, we searched research registers of ongoing studies. We contacted pharmaceutical manufacturers to request unpublished data and searched conference proceedings for the Association for Research in Vision and Ophthalmology (ARVO), and the Annual Congress for the Royal College of Ophthalmologists (RCO). There were no language or date restrictions in the search for trials. The electronic databases were last searched on 15 January 2009.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi RCTs that compared interventions to improve adherence to ocular hypotensive therapy for patients with OHT or glaucoma.

DATA COLLECTION AND ANALYSIS

At least two authors independently assessed the search results for eligibility and extracted data for included trials onto specifically designed forms. We calculated the mean difference for continuous data and relative risks for dichotomous data. Where appropriate, we pooled data using a fixed-effect model.

MAIN RESULTS

Eight trials met the inclusion criteria. There was considerable heterogeneity of interventions and reported outcome measures and therefore, meta-analysis was limited to two studies. Overall, studies were not of high quality due to small sample sizes, missing data and short term follow-up. Three of five drug comparison studies provided evidence that reducing the frequency of drops can improve adherence. However, the study that compared the least frequent regime with one of the most complicated, showed no difference in reported adherence. A small study of thirteen patients found a reminder device beneficial to adherence levels yet only one of two studies involving education and individualised care planning was found to be successful.

AUTHORS' CONCLUSIONS

Interventions involving simplified dosing regimes, reminder devices, education and individualised care planning, did show improvements in adherence rates. However, due to inadequate methodological quality and heterogeneity of study design we are unable to advocate any particular interventions at this time.

Evaluation of aqueous humor concentrations of Istalol and Betimol following a single ocular instillation in rabbit eyes

PURPOSE

The aim of this study was to evaluate the pharmacokinetic absorption profiles of two commercially available ophthalmic solutions following a single instillation into each eye of New Zealand white rabbit eyes.

METHODS

A single dose of either timolol maleate with potassium sorbate (TLA) or timolol hemihydrate (THH) was instilled into each eye of New Zealand white rabbits (15 rabbits/drug preparation, 50-microL dose). Animals were euthanized 15, 30, 60, 120, and 180 min after instillation, with 3 animals/drug/time intervals. Aqueous humor from both eyes of each animal was pooled and analyzed for timolol concentration, using the high-performance liquid chromatography method.

RESULTS

TLA reached a mean peak concentration of 3.705 +/- 0.3012 microg/mL at 15 min, tapering to 0.539 +/- 0.1431 microg/mL by 180 min. THH reached a mean peak concentration of 2.239 +/- 0.1430 microg/mL at 15 min postinstillation, tapering to 0.148 +/- 0.0282 microg/mL by 180 min.

CONCLUSIONS

TLA containing potassium sorbate demonstrated an absorption profile of more rapid absorption (1.7 fold greater at 15 minutes) and longer residences time (3.6 fold greater at 180 minutes) than the THH. At every time point throughout the study, TLA demonstrated greater drug concentration than THH.

Effects of topical levobunolol or fixed combination of dorzolamide-timolol or association of dorzolamide-levobunolol on intraocular pressure, pupil size, and heart rate in healthy cats

The effects of topical levobunolol with the fixed combination of 2% dorzolamide-0.5% timolol and the association of 2% dorzolamide with 0.5% levobunolol on intraocular pressure (IOP), pupil size (PS), heart rate (HR), and conjunctival hyperemia in eighteen halthy cats were investigated and compared. IOP, PS, HR, and conjuntival hyperemia were daily recorded at three times (9a.m., 2p.m., and 6p.m.). Three groups were formed (n=6), and one eye of each animal was randomly selected and treated with topical levobunolol (L), or commercial combination of dorzolamide-timolol (DT), or the association of dorzolamide with levobunolol (DL). The first day (0) consisted of recording of baseline values. On the next four consecutive days, drugs were instilled at 8a.m. and 8p.m. and measurements were taken at the same times fore cited. Comparing with the baseline values, all evaluated parameters significantly decreased (P<0.001). Conjuntival hyperemia was not seen. Levobunolol significantly declined IOP, PS, and HR in normal cats, and showed a stronger effect in lowering HR, when compared to dorzolamide-timolol effect. No synergistic effect in IOP declining was noted when levobunolol dorzolamide was added to levobunolol.

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.

Improvement of the ocular bioavailability of timolol by sorbic acid

The ocular bioavailability of timolol increased in sorbic acid solution due to ion pair formation. Its octanol/water partition coefficient also increased, suggesting the formation of a more lipophilic complex. The concentration of timolol in rabbit aqueous humor was determined after instillation of timolol ophthalmic solution containing sorbic acid. When the molar ratio of sorbic acid to timolol was two or higher, the concentration of timolol in the aqueous humor was higher than with timolol alone. In the presence of sorbic acid the maximal aqueous humor concentration and the area under the curve were more than two-fold higher than those of Timoptol, a timolol maleate ophthalmic solution, and similar in value to TIMOPTIC-XE, a gel-forming ophthalmic solution. To investigate the transcorneal absorption mechanism, in vitro permeation profiles across the intact and de-epithelialyzed cornea were analyzed on the basis of the bilayer diffusion model. The partition coefficient in the epithelium was about twice as high in the presence of sorbic acid than with timolol alone, although the diffusion coefficient in the epithelium did not change. We conclude that the improved ocular bioavailability in the presence of sorbic acid is due to increased partitioning of timolol in the corneal epithelium.

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.