Systemic side effects of topical beta-adrenergic blockers

The association between antiglaucomatous agents and Alzheimer's disease

OBJECTIVES

To estimate the risk of Alzheimer's disease (AD) associated with long-term use of topical glaucoma medications among middle-aged and older glaucoma patients, and compare the AD risk among various glaucoma subtypes.

METHODS

This nationwide population-based cohort study utilized insurance claims data from Taiwan's National Health Insurance Research Database between 2008 and 2019. Participants were adults aged 45 years or older either with a diagnosis of glaucoma or without. Those with glaucoma must have received single antiglaucomatous medication (including α2-adrenergic agonists, cholinergic agonists, beta-blockers, prostaglandin analogs, and pilocarpine) for over 90 days. Those with pre-existing AD diagnoses prior to the index date were excluded.

RESULTS

A total of 202,000 participants were included in the study, with 101,000 in each group (glaucoma and control groups). Glaucoma patients on topical alpha-2 adrenergic agonist monotherapy exhibited a significantly higher AD risk (aHR 1.15, 95% CI = 1.01-1.31) compared to those on beta-blockers. Glaucoma was further categorized into primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), primary angle-closure glaucoma (PACG), and unspecified glaucoma. Irrespective of the type of glaucoma, individuals with glaucoma had a significantly higher risk of AD compared to those without glaucoma (POAG: aHR 1.23, 95% CI = 1.08-1.40; NTG: aHR 1.49, 95% CI = 1.19-1.85; PACG: aHR 1.35, 95% CI = 1.19-1.52; unspecified glaucoma: aHR 1.36, 95% CI = 1.23-1.50).

CONCLUSIONS

Topical alpha-2 adrenergic agonists might pose increased AD risk in individuals with glaucoma compared to beta-blockers. Accordingly, their utilization should be undertaken judiciously, especially in middle-aged and older populations. Our findings also indicate glaucoma may increase the risk of AD regardless of glaucoma subtype.

How latanoprost changed glaucoma management

Glaucoma is currently considered one of the leading causes of severe visual impairment and blindness worldwide. Topical medical therapy represents the treatment of choice for many glaucoma patients. Introduction of latanoprost, 25 years ago, with an entirely new mechanism of action from that of the antiglaucoma drugs used up to that time was a very important milestone. Since then, due mainly to their efficacy, limited systemic side effects and once daily dosing, prostaglandin analogues (PGAs) have become as the first-choice treatment for primary open-angle glaucoma. PGAs are in general terms well tolerated, although they are associated with several mild to moderate ocular and periocular adverse events. Among them, conjunctival hyperemia, eyelash changes, eyelid pigmentation, iris pigmentation and hypertrichosis around the eyes are the most prevalent. The objective of this paper is to review the role of PGAs in the treatment of glaucoma over the 25 years since the launch of Latanoprost and their impact on clinical practice outcomes.

Efficacy and safety of timolol-dorzolamide fixed-combination three times a day versus two times a day in newly diagnosed open-angle glaucoma

Objective

This study aimed to compare the therapeutic efficacy and safety of dorzolamide/timolol fixed-combination(Cosopt) in newly diagnosed primary open-angle glaucoma (POAG) patients.

Methods

In this prospective, interventional case series, newly POAG patients were included. Patients were started on Cosopt twice a day (BID) for one month and then switched to three times a day (TDS) for an additional month. Patients underwent comprehensive ophthalmic examination, diurnal intraocular pressure (IOP), blood pressure (BP), and 24-h heart rate (HR) measurements at baseline, month 1(BID), and month 2(TDS). Throughout the study, all adverse events were monitored by the investigators.

Results

In 31 POAG patients that completed the study, the mean baseline IOP was 23.1 ± 3.15 mmHg. IOP was decreased significantly 16.5 ± 2.21 at one month (p < .0001) and 13.9 ± 2.23 mmHg at 1 and 2 months follow up (p < .0001). IOP was significantly lower in month 2 compared to month 1 (p = .0004). While Cosopt BID significantly reduced the mean 24-h systolic BP and mean 24-h HR from baseline (p < .0001), the mean 24-h systolic BP and HR remained unchanged with Cosopt TDS compared to BID (p = .62).

Conclusions

Cosopt TDS has a superior IOP-lowering effect than Cosopt BID in POAG patients with comparable safety profiles.

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.

Prolonged central nervous system and respiratory depression in preterm neonates after exposure to brimonidine tartrate and timolol maleate ophthalmic drops

Objective: We report three cases of preterm neonates who presented with central nervous system (CNS) and respiratory depression after inadvertent exposure to brimonidine tartrate 0.2% and timolol maleate 0.5% fixed-combination ophthalmic drops. Case descriptions: CNS and respiratory depression were observed in the three neonates within two hours of administration of brimonidine tartrate 0.2% and timolol maleate 0.5% eye drops. Respiratory support was initiated upon admission to the neonatal intensive care unit (NICU). The effects of the drug combination lasted for 24 to 48 hours. Conclusion: This case series suggests that the drug combination of brimonidine tartrate and timolol maleate causes a prolonged depression of the central nervous and respiratory systems in preterm neonates.

Multiple drug delivery from the drug-implants-laden silicone contact lens: Addressing the issue of burst drug release

A fixed combination of bimatoprost/timolol eye drop solution is used to manage the elevated intra-ocular pressure in glaucoma patients, including individuals whose condition is poorly controlled by monotherapy. Eye drop solutions are generally given in high dose, due to poor ocular bioavailability. The high ocular dose of bimatoprost and timolol lead to hyperaemia and systemic cardiac side effects respectively. Here, we introduce multiple implant-laden contact lenses (IM) to passively deliver timolol, bimatoprost and hyaluronic acid at therapeutically relevant doses without high burst release. The drug-loaded implants were individually implanted in the outer periphery of the silicone contact lenses. Atomic force microscopy showed the smooth surface of the implant contact lens, as the implants were inside the contact lens matrix. The implant lens (IM) showed major loss of drugs [timolol = 60.60%, bimatoprost = 61.75% and HA = 46.03%] during the monomer extraction and wet sterilization, while the option of dry radiation sterilization (IM-R lens) and hydration for 24 h prior to use showed relatively lower loss of drugs [timolol = 16.87%, bimatoprost = 47.95% and HA = 24.41%]. The in-vitro drugs release data of IM-R lens, showed sustained release for 72 h, with low burst release in comparison to the soaked (SM) and direct drug-laden contact lenses (DL). The in vivo drug release data in the rabbit tear fluid showed sustained release using IM-R lens in comparison to the SM lens and eye drop therapy. The burst release with the IM-R lens was many folds reduced, which could bypass the side effects associated with multiple eye drop therapy. The in vivo pharmacodynamic study in the rabbit model showed peak and valley profile with multiple eye drop therapy, while IM-R lens showed prolong reduction in intra ocular pressure (IOP) for 120 h. The study demonstrates the application of implantation technology to deliver multiple drug through contact lenses to treat glaucoma.

Ophthalmic Timolol and Hospitalization for Symptomatic Bradycardia and Syncope: A Case Series

Topical beta-blockers are commonly used for the management of primary open angle glaucoma (POAG). One of the rare but serious side effects of the topical beta-blockers is bradycardia, defined as a heart rate below 60 beats per minute. In few cases, the heart rate drops to much lower level resulting in syncope or symptomatic bradycardia. Topical beta-blockers are still widely used for POAG even though there are much better medications available. We present a series of four cases of symptomatic bradycardia resulting from the use of timolol eye drops and after discontinuation of the eye drops, heart rate improved to normal range (60-100 beats per minute).

New technique to reduce systemic side effects of timolol eye drops: The tissue press method-Cross-over clinical trial

IMPORTANCE

Nasolacrimal occlusion (NLO) is effective in reducing systemic absorption of eye drop medication but it is difficult and often performed poorly. We propose an alternative easier and equally effective technique.

BACKGROUND

To test the effectiveness of systemic absorption, we evaluated plasma concentration and ocular effects after topically administered timolol and compared to NLO.

DESIGN

Cross-over trial carried out in Capital Eye Specialist, Wellington.

PARTICIPANTS

A total of 21 subjects over 18 years without contraindications for topical beta-blocker medication and not using systemic beta-blockers.

METHODS

During three clinic visits separated by at least one week, alternative approaches to reduce systemic eye drop absorption were tested. These were: (a) nasolacrimal (punctal) occlusion for 5 min, (b) tissue press method or (c) no intervention. Timolol plasma levels were measured 1 h after drop application. At each visit, baseline measurement of blood pressure, heart rate and intraocular pressure (IOP) were performed, and repeated 1 h after timolol 0.5% eye drop application.

MAIN OUTCOME MEASURES

Comparison of timolol plasma concentration after each intervention. Secondary outcome measurements included effects on blood pressure, heart rate and IOP.

RESULTS

Plasma timolol concentrations after tissue press method and NLO were significantly lower than those without intervention. Comparing tissue press method to NLO, there were no significant differences in plasma levels of timolol, blood pressure, heart rate or IOP.

CONCLUSION AND RELEVANCE

The tissue press method is equally effective as NLO in reducing systemic absorption of timolol. It is also easier and faster to administer.

Daylight-Mediated, Passive, and Sustained Release of the Glaucoma Drug Timolol from a Contact Lens

Timolol, a potent inhibitor of β-adrenergic receptors (βARs), is a first-line drug for decreasing the intraocular pressure (IOP) of patients with glaucoma. Timolol is administered using 0.5% eye-drop solutions at >3 × 107 times the inhibitory concentration (k i) for βARs. This high dose is wasteful and triggers off-target effects that increase medication noncompliance. Here, we introduce contact lenses that release timolol to the eye throughout the day during passive exposures to natural daylight at a more therapeutically relevant concentration (>3000 k i). Timolol is coupled to the polymer of the contact lens via a photocleavable caged cross-linker and is released exclusively to the surrounding fluid after the 400-430 nm mediated cleavage of the cross-linking group. Studies conducted in a preclinical mouse model of glaucoma show photoreleased timolol is effective as authentic timolol in reducing IOP. Our studies highlight several advantages of daylight-mediated release of timolol from lenses compared to eye-drops. First, fitted contact lenses exposed to natural daylight release sufficient timolol to sustain the inhibition of βARs over a 10 h period. Second, the contact lenses inhibit βARs in the eye using only 5.7% of the timolol within a single eye-drop. Third, the lenses allow the patient to passively control the amount of timolol released from the lens-for example, early morning exposure to outdoor sunlight would release enough timolol to maximally reduce the IOP, whereas subsequent periodic exposures to indoor daylight would release sufficient timolol to overcome the effects of its spontaneous dissociation from βARs. Fourth, our lenses are disposable, designed for single day use, and manufactured at a low cost.

Merkel Cells Activate Sensory Neural Pathways through Adrenergic Synapses

Epithelial-neuronal signaling is essential for sensory encoding in touch, itch, and nociception; however, little is known about the release mechanisms and neurotransmitter receptors through which skin cells govern neuronal excitability. Merkel cells are mechanosensory epidermal cells that have long been proposed to activate neuronal afferents through chemical synaptic transmission. We employed a set of classical criteria for chemical neurotransmission as a framework to test this hypothesis. RNA sequencing of adult mouse Merkel cells demonstrated that they express presynaptic molecules and biosynthetic machinery for adrenergic transmission. Moreover, live-cell imaging directly demonstrated that Merkel cells mediate activity- and VMAT-dependent release of fluorescent catecholamine neurotransmitter analogs. Touch-evoked firing in Merkel-cell afferents was inhibited either by pre-synaptic silencing of SNARE-mediated vesicle release from Merkel cells or by neuronal deletion of β₂-adrenergic receptors. Together, these results identify both pre- and postsynaptic mechanisms through which Merkel cells excite mechanosensory afferents to encode gentle touch. VIDEO ABSTRACT.

The Efficacy and Safety of Timolol Maleate versus Brinzolamide Each Given Twice Daily Added to Travoprost in Patients with Ocular Hypertension or Primary Open-Angle Glaucoma

PURPOSE

To compare the efficacy and safety of timolol maleate 0.5% versus brinzolamide 1% when added to travoprost 0.004% in patients with ocular hypertension or primary open-angle glaucoma.

DESIGN

A prospective, double-masked, randomized, active-controlled, parallel comparison.

METHODS

Qualified patients at Visit 1 were placed on travoprost dosed every evening for 4 weeks and then were randomized at baseline (Visit 2) to the addition of timolol maleate or brinzolamide each given twice daily. Patients returned to clinic at Week 4 (Visit 3) for a safety visit and Week 12 (Visit 4) for an efficacy visit. At Visits 2 and 4 the intraocular pressure (IOP) was measured at 08:00, 12:00, and 16:00 hours.

RESULTS

Ninety-seven patients on brinzolamide had a baseline diurnal IOP of 21.5+/-2.2 mmHg and 95 on timolol maleate had 21.3+/-2.5 mmHg, each added to travoprost. The diurnal mean IOP at Week 12 was 18.1+/-2.7 mmHg for brinzolamide and 18.1+/-3.0 mmHg for timolol maleate (p=0.96). There was no statistical difference found between treatment groups in the absolute level of pressure, or in the reduction in IOP from baseline, at each time point or for the diurnal curve (p>0.05). There was no significant difference for any adverse event between groups (p>0.05), with the most common side effect being conjunctival hyperemia in 15/97 (16%) brinzolamide and 6/95 (6%) timolol treated patients (p=0.06).

CONCLUSIONS

This study showed that brinzolamide provides similar safety and efficacy compared to timolol maleate when added to travoprost.

Timolol Eye Drops Induced Bradycardia

We report a 25-year-old man with bradycardia after administration of ophthalmic timolol. The patient was asymptomatic, and his bradycardia resolved after stopping the eye drop. He was discharged after a four-hour observation. This case demonstrated that topical timolol eye drop may cause systemic adverse reaction. The use of timolol and its possible side-effects are discussed.

Ultrasound-promoted dispersive micro solid-phase extraction of trace anti-hypertensive drugs from biological matrices using a sonochemically synthesized conductive polymer nanocomposite

In this work, a rapid and efficient procedure named ultrasound meliorated dispersive micro solid-phase extraction followed by high performance liquid chromatography-ultra violet detection (US-D-μSPE-HPLC-UV) was developed for the pre-concentration of the main trace anti-hypertensive drugs in complex matrices. The basis of this procedure was a polypyrrole-sodium dodecylbenzenesulfonate/zinc oxide (PPy-DBSNa/ZnO) nanocomposite. It was readily synthesized by the impressive way of in situ sonochemical oxidative polymerization in the presence of some additives such as FeCl₃ and DBSNa, ultimately leading to the effective coating of PPy on the ZnO nanoparticle cores. Characterization of the proposed nanosorbent was performed by different techniques such as FESEM, XRD,EDX, and TGA, confirming the high quality and proper physico-chemical properties of the proposed sorbent. In order to better investigate the input variables, the central composite design (CCD) combined with the desirability function (DF) was utilized. The enriched optimum conditions consisted of the initial pH value of 11.8, 15mg of the PPy-DBSNa/ZnO nanocomposite, a sonication time of 4.6min, and 100μL of methanol, resulting in maximum responses at a relatively low extraction time with a logical DF. Under the optimum conditions, good linearity (5-5000, 2.5-3500, and 2.5-3000ngmL^-1 for metoprolol, propranolol, and carvedilol, respectively, with the correlation of determinations (R²s) higher than 0.99), low limits of detection (LODs) (0.8-1.5ngmL^-1), proper repeatabilities (relative standard deviation values (RSDs) below 6.3%, n=3), reasonable enrichment factors (EFs) (60-72), and good extraction recoveries (ERs) (higher than %75) were obtainable. These appropriate validations corroborated a good effectiveness of ultrasonic waves in the achievement of a supreme solid phase as well as a facile and efficient microextraction of the low therapeutic concentrations in human plasma and urine samples.

Adverse Events in Young and Preterm Infants Receiving Topical Timolol for Infantile Hemangioma

BACKGROUND

The success of oral propranolol for treatment of infantile hemangiomas (IHs) has led practitioners to use topical β-blockers. In preterm infants, clinicians frequently turn to topical timolol, with the presumption that topical application will result in less systemic absorption. We used Holter monitoring to assess for drug-induced bradycardia in high-risk infants.

METHODS

We retrospectively reviewed the charts of 22 at-risk infants who received a Holter monitor to assess for association between timolol administration and development of significant bradycardia.

RESULTS

Four infants had episodic bradycardia detected by Holter monitoring. Two of these infants were full term; weighed more than 3,000 g; and had rare, brief, asymptomatic episodes unrelated to the timing of the timolol application. The other two infants had symptomatic bradycardia while on timolol and were the only two babies that weighed less than 2,500 g at initiation of therapy. Both were young (postmenstrual age [PMA] 34 and 37 wks) at initiation and had a timolol dose above the average exposure for the cohort.

CONCLUSION

In this cohort of at-risk infants, topical timolol appeared to provide safe treatment for IHs in full-term infants receiving a dose of less than 0.2 mg/kg/day, but infants with a PMA of less than 44 weeks and weight at treatment initiation of less than 2,500 g may be at risk of adverse events, including bradycardia, hypotension, apnea, and hypothermia. We recommend close monitoring of temperature, blood pressure, and heart rate in premature and low-birthweight infants with IHs at initiation of and during therapy with topical timolol.

Association between Ophthalmic Timolol and Hospitalisation for Bradycardia

Introduction. Ophthalmic timolol, a topical nonselective beta-blocker, has the potential to be absorbed systemically which may cause adverse cardiovascular effects. This study was conducted to determine whether initiation of ophthalmic timolol was associated with an increased risk of hospitalisation for bradycardia. Materials and Methods. A self-controlled case-series study was undertaken in patients who were hospitalised for bradycardia and were exposed to timolol. Person-time after timolol initiation was partitioned into risk periods: 1–30 days, 31–180 days, and >180 days. A 30-day risk period prior to initiating timolol was also included. All remaining time was considered unexposed. Results. There were 6,373 patients with at least one hospitalisation for bradycardia during the study period; 267 were exposed to timolol. Risk of bradycardia was significantly increased in the 31–180 days after timolol initiation (incidence rate ratio (IRR) = 1.93; 95% confidence interval (CI) 1.00–1.87). No increased risk was observed in the first 30 days or beyond 180 days of continuous exposure (IRR = 1.40; 95% CI 0.87–2.26 and IRR = 1.21; 95% CI 0.64–2.31, resp.). Conclusion. Bradycardia is a potential adverse event following timolol initiation. Practitioners should consider patient history before choosing a glaucoma regime and closely monitor patients after treatment initiation with topical nonselective beta-blocker eye drops.

Can ophthalmic drops cause central nervous system depression and cardiogenic shock in infants?

Topical ocular medications have been widely prescribed and successfully used in children for the management of different ophthalmic disorders. We present 2 infants admitted to our pediatric intensive care unit who developed altered state of consciousness, hypotonia, hypothermia, bradycardia, and apnea after instillation of ophthalmic drops. The second infant also had hypotension and broncho-obstruction. Few days before admission, both infants were diagnosed with congenital glaucoma, and topical antiglaucoma treatment was initiated. Ophthalmic drops with brimonidine and brinzolamide were prescribed to both patients, whereas the second infant also received topical timolol. After elimination of other possible causes, the diagnosis of intoxication with topical antiglaucoma medications was established. After discontinuation of eye drops and vigorous symptomatic treatment, both infants recovered without sequels. Topically applied ophthalmic drops may cause life-threatening systemic adverse effects in infants, such as central nervous system depression and cardiogenic shock. Moreover, these 2 patients illustrate the importance of careful evaluation of all topical medications and their consideration as possible causes of the derangements in critically ill infants.

Long-term cost and efficacy analysis of latanoprost versus timolol in glaucoma patients in Germany

AIM

To evaluate 5-year effectiveness and cost between latanoprost or timolol monotherapy in a pilot trial.

METHODS

A retrospective, multi-center trial performed at 6 sites in Germany of patients who had a diagnosis of primary open-angle or pigmentary glaucoma, in at least one eye, initiated on monotherapy with latanoprost or timolol maleate. Qualified consecutive charts were reviewed in which 5-year efficacy, safety and cost data was abstracted.

RESULTS

Seventy-seoen latanoprost and 49 timolol patients were included, at the final visit no difference existed between the two groups in disc parameters including: rim area, rim area/disc area ratio, cup volume or vertical cup/disc ratio (P>0.05). There was no difference in intraocular pressure (IOP) between the initial latanoprost (17.4±2.6) and timolol (16.3±2.8mmHg) groups. There was less change in medicines over the follow-up period (0.1 vs 0.8) and fewer medications at the final visit (1.2 vs 1.8) with latanoprost compared to timolol. No patient treated with latanoprost discontinued therapy during follow-up, while 12% discontinued timolol mostly due to inadequate IOP control. Cost/year was less with initial timolol ($458±236) as compared to latanoprost ($552±202).

CONCLUSION

Patients begun on latanoprost or timolol and followed over 5 years may have similar clinical outcomes. However, timolol patients may require more medicines and medicine changes to control IOP for long-term, but at a lower cost.

Development of a specific questionnaire measuring patient satisfaction with glaucoma treatment: Glausat

OBJECTIVE

Patient satisfaction with glaucoma therapy is one of the aspects that affects adequate adherence to treatment; therefore, it would be interesting to measure the satisfaction properly. We present the development process and psychometric properties of a new instrument for measuring patient satisfaction with glaucoma treatment.

MATERIAL AND METHODS

After collection and discussion of contents, a 38-item questionnaire was proposed and arranged into seven theoretical domains. The questionnaire was applied to a sample of 194 patients and its length was reduced using an exploratory factor analysis. Psychometric properties were assessed under classic theory.

RESULTS

The final questionnaire is formed by 22 items grouped into seven dimensions: expectations and beliefs about treatment, ease of use, efficacy, undesired effects, impact on health-related quality of life, medical care, and general satisfaction with treatment. Some dimensions correlated slightly. The reliability of the dimensions ranged from 0.77 to 0.93. Confirmatory factor analysis revealed an additional support of the proposed structure (chi(2) (188) = 217, P = 0.073). Glausat scores were proven to correlate with patients' self rating on medication tolerability, and with clinicians' assessment of tolerability, effectiveness and compliance.

CONCLUSIONS

The Glausat questionnaire has proven to be reliable and structurally valid. This instrument may be used to assess patients' satisfaction with glaucoma treatment.

Risk factors for subject withdrawals in clinical trials evaluating glaucoma medications

BACKGROUND

To evaluate risk factors for subject withdrawals from multicenter clinical trials evaluating glaucoma medications.

METHODS

An analysis of prospective, randomized, multicenter, parallel, active-controlled clinical trials with 70 subjects/treatment arm published from 1996-2008.

RESULTS

We analyzed 36 glaucoma studies including 17,511 subjects at 1,294 clinical sites. There were 2,060 (12%) subject withdrawals with 669 (32%) for administrative errors, 945 (46%) for adverse events (AEs), 197 (10%) for inadequate intraocular pressure (IOP) control and 249 (12%) for unknown reasons. By multilinear regression analysis, no positive risk factors for early subject withdrawals were observed following a Bonferroni correction (p > or = 0.01). A positive correlation was observed for medication errors and protocol violations to withdrawals due to ocular AEs and total administrative errors (p < 0.0001). Protocol violations alone were correlated to subject withdrawals for any AE (total/month) and systemic AEs (p < 0.0001). Females and Caucasians were correlated to medication errors (p < 0 .0001). Among medical therapies, alpha-agonists, beta-blockers, the carbonic anhydrase inhibitor/beta-blocker fixed combination and prostaglandins were correlated with systemic AEs (p < or = 0.005) while the alpha-agonists were correlated with withdrawals for poor IOP control (p = 0.00056).

CONCLUSIONS

Subject withdrawals from clinical trials for total administrative errors or AEs potentially might be reduced by choosing sites with lower historical rates of protocol violations or medication dispensing errors. Drug class choice also may influence subject withdrawals for AEs and poor IOP control.

24-hour intraocular pressure and blood pressure levels with latanoprost/timolol fixed combination versus timolol

PURPOSE

To evaluate 24-hr intraocular pressure (IOP) and blood pressure (BP) with timolol or latanoprost/timolol fixed combination (LTFC).

METHODS

Patients with primary open-angle glaucoma or ocular hypertension with normal blood pressure were randomized to LTFC, dosed each evening, or timolol dosed twice daily in a cross-over design for 8 weeks and the opposite medicine for 8 weeks. IOP was measured at 02:00, 06:00, 10:00, 14:00, 18:00 and 22:00 hours in the sitting position with Goldmann applanation tonometry and BP monitoring every 30 min while awake and every hour while asleep at the end of each 8-week treatment period.

RESULTS

Twenty-nine patients had a 24-hr baseline IOP of 26.3 +/- 2.5 mmHg, systolic BP (SBP) of 121.4 +/- 12.4 mmHg, diastolic BP (DBP) 72.9 +/- 7.1 mmHg, and ocular perfusion pressure (OPP) of 33.9 +/- 5.7 mmHg. No statistical differences were found between untreated and treated 24-hr SBP, DBP, mean BP (MBP), heart rate, or nocturnal BP dipping status with either medication. LTFC lowered IOP more at each timepoint compared to timolol (difference between treatments 2.7 mmHg, p = 0.0002).

CONCLUSIONS

Neither timolol or evening-dosed LTFC reduced SBP, DBP, MBP, OPP, or increased nocturnal dipping. LTFC was more effective than timolol in decreasing IOP.

Changing therapeutic paradigms in glaucoma management

Glaucoma is a family of diseases commonly characterised by progressive optic neuropathy with associated visual field deficits for which elevated intraocular pressure (IOP) is one of the primary risk factors. For more than a century the main goal of glaucoma management has been to eliminate the risk associated with elevated IOP. In recent years, accumulating evidence of pressure-independent causes of glaucomatous optic neuropathy has led to the recognition that lowering IOP alone may often be insufficient for the long-term preservation of visual function. An innovative therapeutic approach is now emerging to prevent progression of glaucomatous optic neuropathy and preserve vision, irrespective of disease aetiology: direct protection of the optic nerve. In addition to reducing the risk associated with elevated IOP, this neuroprotective approach will augment the overall goal of preserving the optic nerve through direct promotion of retinal ganglion cell (RGC) survival and/or prevention of RGC death. Although no currently available compounds have been clinically demonstrated to provide neuroprotective benefit in glaucoma, recent preclinical studies have shown that alpha-adrenergic agonists, such as brimonidine, provide neuroprotective benefits, as well as excellent IOP lowering efficacy. In addition, new agents with promising neuroprotective utility that are emerging from other studies are now being investigated for efficacy in glaucoma. The review discusses recently introduced compounds and new drugs in development with regard to their potential value in conventional and/or neuroprotective strategies for vision sparing in glaucoma.

Intraocular pressure and safety in glaucoma patients switching to latanoprost/timolol maleate fixed combination from mono- and adjunctive therapies

PURPOSE

The aim of this study was to evaluate the efficacy and safety in ocular hypertensive or open-angle glaucoma patients changed to a latanoprost/timolol fixed combination (LTFC) from previous therapy.

METHODS

We employed a retrospective, multicenter, active-controlled study evaluating patients who had a previous therapy substituted with LTFC and had a 3-month follow-up.

RESULTS

In the 168 patients included in the trial, LTFC reduced the intraocular pressure (IOP) after switching from previous therapies: timolol (22.8+/-3.5 to 19.0+/-3.9 mmHg, N=49, p<0.001), latanoprost (21.2+/-3.8 to 18.3+/-2.5 mmHg, N=54, p<0.001), and a dorzolamide/timolol fixed combination (20.9+/-2.4 to 20.0+/-2.7 mmHg, N=32, p=0.03). In switching from a latanoprost and timolol unfixed combination, the pressure changed from 18.3+/-3.8 to 18.9+/-3.0 mmHg (N=33, p=0.38). LTFC was persistent in 131 (78%) patients within the 3-month treatment period. The most common adverse event with LTFC was conjunctival hyperemia, which occurred in patients not previously treated with latanoprost therapy (N=16, 10%).

CONCLUSIONS

LTFC generally provides reduced IOP and limited side effects when substituted for other common glaucoma therapies, while providing similar pressure when switched from its own individual components.

Short term efficacy and safety in glaucoma patients changed to the latanoprost 0.005%/timolol maleate 0.5% fixed combination from monotherapies and adjunctive therapies

AIMS

To evaluate efficacy and safety in patients with ocular hypertension or open angle glaucoma changed to latanoprost/timolol fixed combination (LTFC).

METHODS

A prospective, multicentre, historical control in which qualified patients had their previous therapy substituted by LTFC and were followed for at least 2 months.

RESULTS

In 1676 patients LTFC was continued in 93% throughout the observation period. In all patients LTFC reduced the intraocular pressure (IOP) from 20.6 (SD 3.8) to 17.7 (3.0) mm Hg (p<0.001) compared to previous monotherapies including latanoprost, timolol, alpha agonists or carbonic anhydrase inhibitors (CAI). LTFC provided more efficacy after changing from adjunctive therapies including: a beta blocker added to either CAI, alpha agonist, or pilocarpine, or CAI added to an alpha agonist, or latanoprost added to either CAI, alpha agonist, or beta blocker (unfixed combination), and travoprost added to timolol (p<0.007). LTFC was as effective as latanoprost used with dorzolamide/timolol fixed combination (-0.9 mm Hg, p = 0.1792). The most common reason to discontinue therapy was lack of efficacy (n = 70, 4%) and adverse event (n = 17, 1%).

CONCLUSION

In a clinical setting, patients who have their monotherapy or adjunctive therapy substituted with LTFC may experience reduced IOP, good tolerability, and continuation of therapy for the first 2-3 months of treatment.

High-resolution functional vascular assessment with ultrasound

In order to improve the resolution of contrast-assisted imaging systems, we have created a high-frequency destruction/contrast replenishment imaging system with a spatial resolution of 160 microm x 160 microm. The system utilizes a 1-MHz cylindrically focused transducer for destruction and a 25-MHz spherically focused transducer for pulse/echo imaging. Speckle tracking and a clutter filter are applied across frames to remove the challenging physiologic motion artifacts that are obtained when imaging with a mechanically scanned transducer. Using a new estimation technique, flow constants proportional to absolute flow rate were estimated from B-mode time-intensity curves (TICs). The in vitro results indicate a correlation between the actual flow velocity and the estimated rate constant. In vivo images are presented showing blood perfusion in the ciliary processes and iris of the rabbit eye. The regions of interest (ROIs) from the ciliary processes yielded slower perfusion compared with the iris, as expected from vascular casts of the microcirculation in this region. Potential applications of this system include high-resolution perfusion assessment in small animals.

A new measure of patient satisfaction with ocular hypotensive medications: the Treatment Satisfaction Survey for Intraocular Pressure (TSS-IOP)

Purpose

To validate the treatment-specific Treatment Satisfaction Survey for Intraocular Pressure (TSS-IOP).

Methods

Item content was developed by 4 heterogeneous patient focus groups (n = 32). Instrument validation involved 250 patients on ocular hypotensive medications recruited from ophthalmology practices in the Southern USA. Participants responded to demographic and test questions during a clinic visit. Standard psychometric analyses were performed on the resulting data.

Sample

Of the 412 patients screened, 253 consented to participate, and 250 provided complete datasets. The sample included 44% male (n = 109), 44% Black (n = 109) and 57% brown eyed (n = 142) participants, with a mean age of 64.6 years (SD 13.1) and a history of elevated IOP for an average of 8.4 yrs (SD 7.8). A majority was receiving monotherapy (60%, n = 151).

Results

A PC Factor analysis (w/ varimax rotation) of the 31 items yielded 5 factors (Eigenvalues > 1.0) explaining 70% of the total variance. Weaker and conceptually redundant items were removed and the remaining 15 items reanalyzed. The satisfaction factors were; Eye Irritation (EI; 4 items), Convenience of Use (CofU; 3 items), Ease of Use (EofU; 3 items), Hyperemia (HYP; 3 items), and Medication Effectiveness (EFF; 2 items). Chronbach's Alphas ranged from .80 to .86. Greater distributional skew was found for less common experiences (i.e., HYP & EI with 65% & 48.4% ceilings) than for more common experiences (i.e., EofU, CofU, EFF with 10.8%, 20.8% & 15.9% ceilings). TSS-IOP scales converged with conceptually related scales on a previously validated measure of treatment satisfaction, the TSQM (r = .36 to .77). Evidence of concurrent criterion-related validity was found. Patients' symptomatic ratings of eye irritation, hyperemia and difficulties using the medication correlated with satisfaction on these dimensions (r = .30-.56, all p < .001). Clinicians' ratings of IOP control, severity of side effects and problematic medication use correlated with patients' satisfaction scores on these dimensions (r = .13-.26, all p < .01).

Conclusions

This study provides initial evidence that the TSS-IOP is a reliable and valid measure, assessing patients' satisfaction with ocular hypotensive medications.

Conjunctival hyperemia and the use of topical prostaglandins in glaucoma and ocular hypertension

The prostaglandin derivatives are thought to lower intraocular pressure (IOP) primarily by increasing uveoscleral outflow. The ocular side effect, hyperemia, appears to occur via a secondary, unrelated mechanism. Variations in the IOP-lowering effect and incidence of hyperemia associated with these drugs are a function of their different chemical structures. Among the currently approved prostaglandin derivatives, hyperemia occurs in as many as 50% of patients treated with travoprost and as few as 5% of patients treated with latanoprost. The side effect of hyperemia may be of concern to the ophthalmologist for at least 2 reasons: hyperemia may compromise the outcome of filtration surgery, and it may represent a cosmetic problem to the patient thereby leading to non-compliance. The extent to which hyperemia may contribute to patient noncompliance and the effect of administration of the prostaglandin derivatives on outcome of filtration surgery remain to be determined. Until more definitive data are available, when selecting a prostaglandin analogue for ocular hypotensive therapy, it seems prudent to choose an agent with a low incidence of hyperemia.

Cardiovascular effects of timolol maleate, brimonidine or brimonidine/timolol maleate in concomitant therapy

PURPOSE

To examine the influence on maximal exercise performance in young healthy volunteers of timolol 0.5%, brimonidine 0.2% or placebo versus brimonidine 0.2% and timolol 0.5% used concomitantly.

METHODS

The subjects in this prospective, double-masked, crossover comparison were dosed 15 min prior to treadmill testing. A period of 1 week was allowed between tests.

RESULTS

The 20 subjects who completed the trials (average age 24.5 +/- 7.4) had a mean maximum exercise heart rate of 196 +/- 12 bpm for placebo, 182 +/- 13 bpm for timolol, 187 +/- 10 bpm for brimonidine, and 186 +/- 11 bpm for timolol/brimonidine concomitant therapy (p < 0.005). During recovery, the placebo group demonstrated a statistically higher systolic blood pressure (min 6) and pulse (mins 2 and 4) (p < 0.01). In addition, subjects treated with timolol/brimonidine demonstrated more premature contractions (atrial or ventricular) overall during exercise and recovery (p = 0.01). The brimonidine and concomitant treatment groups showed the greatest number of adverse events per subject, the most common of which were dizziness and fatigue (p = 0.031).

CONCLUSION

This study suggests that both timolol and brimonidine, used alone and concomitantly, cause cardiovascular effects consistent with their pharmacology.

Comparison of the cardiovascular effects of unoprostone 0.15%, timolol 0.5% and placebo in healthy adults during exercise using a treadmill test

PURPOSE

To compare the cardiovascular effects of unoprostone 0.15%, timolol 0.5% and placebo in healthy adults during exercise using a treadmill test.

METHODS

Thirty subjects aged 18-37 years (mean age = 24.1 years) were randomized to one of six treatment sequences in a three-treatment, three-period crossover study (William's design). Study medication was instilled b.i.d. for 5 days before visits 2, 3, and 4. Between treatments, study medication was washed out for 9-10 days. Each subject underwent a submaximal treadmill test at visits 2 through 4, 15 min after dosing.

RESULTS

After 15 min of exercise, average heart rates were 143.1 +/- 21.2, 134.5 +/- 20.0 and 145.4 +/- 20.8 bpm for the unoprostone, timolol and placebo treatments, respectively. At no timepoint was there a statistically significant difference between the unoprostone and placebo treatments (p > 0.05). Beginning with the second minute of exercise, timolol produced a greater decrease in heart rate at all timepoints from placebo than unoprostone (p < 0.05). No consistent differences in systolic or diastolic blood pressure were observed between drug treatments (p > 0.05).

CONCLUSIONS

Unlike timolol, unoprostone 0.15% does not reduce exercise-induced heart rate, indicating a lack of clinical effect on systemic beta-adrenergic receptors in young and healthy subjects.

Comparison of once- or twice-daily bimatoprost with twice-daily timolol in patients with elevated IOP : a 3-month clinical trial

OBJECTIVE

To compare the safety, tolerability, and efficacy of bimatoprost 0.03% instilled once daily or twice daily with timolol 0.5% twice daily.

DESIGN

Multicenter, 3-month, randomized, double-masked, interventional comparison trial.

PARTICIPANTS

Patients diagnosed with ocular hypertension or glaucoma (n = 596).

INTERVENTION

Patients received bimatoprost 0.03% ophthalmic solution once daily (8 PM, with vehicle control at 8 AM), bimatoprost 0.03% twice daily (8 AM; 8 PM), or timolol 0.5% twice daily (8 AM; 8 PM) in an uneven 2:2:1 randomization. Scheduled visits were at prestudy, baseline (day 0), weeks 2 and 6, and month 3. Intraocular pressure (IOP) was measured at 8 AM (predose), 10 AM, and 4 PM.

MAIN OUTCOME MEASURES

The primary outcome measure was reduction in IOP in the eye with higher IOP at baseline. Secondary outcome measures included safety variables (adverse events, ophthalmoscopy, biomicroscopy, iris pigmentation, laser-flare meter, visual acuity, visual fields, heart rate, blood pressure, blood chemistry, hematology, and urinalysis).

RESULTS

At month 3, the mean reduction in IOP from baseline at 8 AM was 9.16 mmHg (35.2%) with bimatoprost once daily, 7.78 mmHg (30.4%) with bimatoprost twice daily, and 6.74 mmHg (26.2%) with timolol twice daily. At all follow-up visits, mean IOP reductions were significantly greater in the bimatoprost once daily group than in the timolol group at each time point (8 AM, 10 AM, and 4 PM; P < 0.001). Twice-daily dosing of bimatoprost also provided significantly greater mean reductions in IOP than timolol at most time points but was not as effective as once-daily dosing. Bimatoprost was associated with significantly more hyperemia and eyelash growth than timolol, whereas timolol was associated with significantly more burning and stinging sensation in eyes. Overall, bimatoprost was well tolerated with few discontinuations because of adverse events.

CONCLUSIONS

Bimatoprost 0.03% once daily was safe and statistically superior to timolol 0.5% twice daily in lowering IOP in patients with ocular hypertension or glaucoma. Bimatoprost given once daily consistently provided IOP reductions approximately 2 to 3 mmHg greater than those provided by timolol. Once-daily dosing of bimatoprost, 0.03%, demonstrated greater IOP-lowering effect and better ocular tolerability than twice-daily dosing.

Effect of timolol 0.5% gel and solution on pulmonary function in older glaucoma patients

PURPOSE

To evaluate the effect of timolol maleate solution or gel forming solution versus placebo on pulmonary function in patients with primary open-angle glaucoma or ocular hypertension without reactive airway disease.

METHODS

After a screening visit, each patient was randomized by a Latin square technique to receive placebo twice daily, 0.5% timolol solution twice daily, or 0.5% timolol gel once a day (placebo given as second dose) to each eye for 2 weeks. Subjects then were crossed over to the two other treatments for 2-week treatment intervals. At each visit, patients were received a dose 15 minutes before pulmonary function testing.

RESULTS

This study began with 25 patients, and 20 finished the trial. There was no difference between treatment groups for the forced expiratory volume at one second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio (P > 0.1). The mean FEV1 for timolol solution, timolol gel, and placebo was 2.42 L, 2.45 L, and 2.50 L, respectively. The mean FVC for timolol solution, timolol gel, and placebo was 3.33 L, 3.38 L, and 3.44 L, respectively. No difference in intraocular pressure was observed between the timolol solution (17.1 +/- 3.3 mm Hg) and timolol gel (17.1 +/- 3.6 mm Hg) between the treatment periods (P > 0.1). No difference in side effects was observed between treatment groups (P > 0.05).

CONCLUSIONS

In older patients with primary open-angle glaucoma or ocular hypertension without reactive airway disease, nonselective beta-blockers should not worsen pulmonary function.

Brimonidine 0.2% given two or three times daily versus timolol maleate 0.5% in primary open-angle glaucoma

PURPOSE

To evaluate the efficacy and safety of brimonidine 0.2% two or three times daily versus timolol maleate 0.5% solution twice daily.

METHODS

Patients with primary open-angle glaucoma were randomized by Latin square technique to one of the three treatment sequences in this crossover, prospective double-masked trial. Each treatment period consisted of 6 weeks of chronic dosing followed by a diurnal curve for the intraocular pressure measured at 08:00, 10:00, 16:00, 18:00, 20:00, 22:00, and 24:00 hours. Intraocular pressure was measured by applanation tonometry.

RESULTS

Thirty patients completed this trial. The average diurnal intraocular pressures in the trial were measured for timolol maleate (17.7 +/- 2.7 mm Hg), brimonidine given three times daily (18.0 +/- 2.2 mm Hg), and brimonidine given twice daily (19.2 +/- 2.4 mm Hg). There was a statistical difference between groups (P <.005). When groups were compared by pairs, three times daily dosing with brimonidine and timolol maleate both reduced the pressure more than twice daily brimonidine at every time point past 10:00 hours and for the diurnal curve (P <.05). In contrast, three times daily brimonidine and timolol maleate were statistically similar for the diurnal pressure, and each time point, except timolol maleate, decreased the pressure more at 16:00 (P =.042). Safety was similar between groups.

CONCLUSIONS

This study demonstrated that both timolol maleate twice daily and brimonidine three times daily provide a similar intraocular pressure reduction to each other. Timolol maleate twice daily and brimonidine three times daily provide a greater decrease in pressure in the late afternoon and nighttime hours, compared with brimonidine twice daily.

Effects of systemic beta-blocker therapy on the efficacy and safety of topical brimonidine and timolol. Brimonidine Study Groups 1 and 2

PURPOSE

To determine the impact of coadminstration of systemic beta-blockers on the ocular hypotensive efficacy and safety of topical timolol, a nonselective, beta-blocker, and that of brimonidine, an alpha2-selective adrenergic agonist, in patients with glaucoma or ocular hypertension.

DESIGN

Post hoc evaluation of data collected from two prospective, multicenter, randomized, double-masked, parallel-group, actively-controlled, 12-month clinical trials.

PARTICIPANTS

Of the 926 subjects with ocular hypertension or glaucoma that were enrolled in the two prospective trials, 66 (7.1%) were concurrently maintained on systemic beta-blocker therapy. Of these patients, 34 had been assigned to the brimonidine group and 32 to the timolol group.

METHODS

Subjects instilled into each eye either 1 drop of brimonidine 0.2% or timolol 0.5% twice daily for 1 year. Study subjects within medication treatment groups were classified as to their use or nonuse of concurrent systemic beta-blockers, and mean intraocular pressure (IOP) reduction, adverse events, heart rate, and blood pressure were compared.

MAIN OUTCOME MEASURES

Mean IOP reduction from baseline was the primary efficacy variable. Adverse events and mean changes in heart rate and blood pressure from baseline were the primary safety variables.

RESULTS

Timolol-treated subjects concurrently taking systemic beta-blockers had smaller decreases in IOP, a greater mean change in systolic (at week 2, months 1, 2, 6, and 9; P < or = 0.001) and diastolic blood pressure (months 2 and 6; P < or = 0.02), and a significantly greater mean decrease in heart rate (month 6; P = 0.004) compared with timolol subjects not taking systemic beta-blockers. By contrast, there was a modest enhancement of IOP-lowering efficacy at trough and no effect on blood pressure or heart rate in brimonidine-treated subjects who were concurrently receiving systemic beta-blocker therapy compared with brimonidine subjects not receiving systemic beta-blockers.

CONCLUSIONS

Concurrent systemic beta-blocker therapy had no deleterious effect on ocular hypotensive efficacy and no impact on systemic safety parameters with topical brimonidine, whereas efficacy was reduced and systemic safety parameters were impacted with topical timolol. Ocular hypotensive agents other than beta-blockers, such as the alpha2 agonist brimonidine, may be a more appropriate first-line therapy for ocular hypertension and glaucoma patients concurrently taking systemic beta-blockers.

The evolving pharmacotherapeutic profile of brimonidine, an alpha 2-adrenergic agonist, after four years of continuous use

Since its introduction in 1996, use of brimonidine tartrate 0.2% ophthalmic solution (Alphagan, Allergan), a highly selective alpha 2-adrenergic agonist, has become increasingly popular for the initial and long-term management of ocular hypertension and glaucoma. Recently, ongoing clinical comparison trials of up to three years in length have reported sustained intraocular pressure (IOP) lowering efficacy with brimonidine 0.2% b.i.d., which was comparable with timolol 0.5% (Timoptic; Merck & Co.), accompanied by a favourable tolerability and safety profile. Also, many post-market studies have demonstrated the utility of brimonidine 0.2% b.i.d. as mono- and adjunctive therapy. Furthermore, major inroads have been made in the study of other possible pharmacotherapeutic benefits of brimonidine treatment, namely the potential for neuroprotection. This review will present a brief developmental history and examine key pharmacotherapeutic characteristics of brimonidine, including its receptor selectivity, IOP-lowering mechanism of action and potential neuroprotective activities. Moreover, the literature on brimonidine's efficacy and safety profiles in the treatment of ocular hypertension and glaucoma will be perused, and new four-year data from an ongoing double-masked clinical study comparing brimonidine tartrate 0.2% with timolol 0.5%, b.i.d. will be introduced. Brimonidine 0.2% b.i.d. provided sustained IOP-lowering efficacy comparable to timolol 0.5% b.i.d., with no significant differences at trough or peak during year four of continuous use. Visual fields were well preserved in both treatment groups with 93% of brimonidine patients and 91% of timolol patients showing no change or improvement. Brimonidine continued to appear safe and well-tolerated, with no clinically significant effects on mean heart rate or blood pressure, and no serious drug-related adverse events (AEs). Two out of 36 brimonidine patients developed ocular allergy; both were resolved without sequelae. Overall post-market surveillance found no reports of unexpected or serious drug-related AEs. These long-term results, in conjunction with those reported in the literature, suggest that brimonidine 0.2% b.i.d. is a highly appropriate first- and second-line therapy for long-term management of glaucoma and ocular hypertension. Potential neuroprotective effects of brimonidine therapy, which might provide additional vision sparing benefit, although supported by compelling animal studies, await clinical verification.

Comparison of 24-hour intraocular pressure reduction with two dosing regimens of latanoprost and timolol maleate in patients with primary open-angle glaucoma

PURPOSE

To compare the 24-hour diurnal ocular hypotensive efficacy of two dosing regimens of latanoprost, once daily (8 AM or 10 PM), vs timolol maleate, twice daily.

METHODS

We measured six diurnal intraocular pressure curves (6 AM, 10 AM, 2 PM, 6 PM, 10 PM, and 2 AM) in one randomly selected eye of 34 Greek patients newly diagnosed with primary open-angle glaucoma. The first diurnal curve was an untreated baseline. Patients began taking timolol 0.5%, twice daily, for 2 months. Patients were randomly assigned to latanoprost 0.005% given at 8 AM or 10 PM for 1 month and then changed to the other dosing regimen for 1 month. A diurnal curve was performed after each dosing period.

RESULTS

The baseline diurnal pressure for all 34 subjects was 23.1 +/- 3.7 mm Hg. The average intraocular pressures at 6 AM for patients who were given latanoprost in the evening (17.9 +/- 2.9 mm Hg) was statistically lower than that in patients given timolol solution (20.1 +/- 2.5 mm Hg, P = .003); however, patients who were given timolol demonstrated a similar diurnal intraocular pressure (19.1 +/- 2.8 mm Hg) to both morning (18.8 +/- 3.7 mm Hg) and evening doses (18.8 +/- 3.6 mm Hg) of latanoprost (P =.329). When the two latanoprost dosages were compared directly, evening administration provided a statistically lower intraocular pressure at 10 AM (P = .0001) and morning administration at 10 PM (P = .0001). This study had an 80% power to exclude a 1.2-mm Hg difference between groups.

CONCLUSIONS

This study indicates that in a small population, both latanoprost and timolol are effective in lowering intraocular pressure throughout a 24-hour period; however, latanoprost is most effective in the 12-hour to 24-hour period after administration.

Systemic beta-blockade with once daily Betimol or Timoptic-XE

The purpose of this study was to evaluate the effect of timolol hemihydrate 0.5% (Betimol [THH], Ciba Vision Ophthalmics) and timolol maleate gel forming solution 0.5% (Timoptic-XE , [TXE], Merck, Inc.), when both are dosed once daily on the exercise performance. Maximum exercise heart rate reflects systemic beta-blockade activity. Fourteen healthy subjects were randomized to receive either placebo (HypoTears , Ciba Vision Ophthalmics), THH, or TXE by a Latin square technique in a three period crossover design. Subjects were dosed one drop every morning beginning three days before exercise testing. The interval between each test was one week. Exercise testing was performed two hours after dosing. Maximum exercise heart rate showed no statistical difference between TXE and THH (174 +/- 13.1 vs. 172 +/- 14.9 beats/min, respectively, P = 0.72). Both active treatments, however, decreased heart rate compared to placebo (185 +/- 7.3 beats/min, P = 0.017). Time to exhaustion showed no difference between groups (P > 0.10). The double product (product of heart rate and systolic blood pressure) did not show a difference between TXE and THH (P = 0.38) but was reduced compared to placebo (P = 0.0053). One subject on TXE was discontinued from the study after the first exercise test because of secondary heart block during the recovery period. It was concluded that TXE and timolol hemihydrate solution show similar systemic beta-blockade activity when both are dosed once a day.

The safety and efficacy of switching timolol maleate 0.5% solution to timolol hemihydrate 0.5% solution given twice daily

This study was undertaken to evaluate the safety and efficacy of switching patients treated with timolol maleate to timolol hemihydrate. In patients with ocular hypertension or chronic open-angle glaucoma treated with beta-blockers for at least three months, we prescribed timolol maleate solution 0.5% given twice daily for one month. We then switched each patient to timolol hemihydrate solution 0.5% (Betimol, Ciba Vision Ophthalmics) given twice daily for three months. This study found over the first three months in 30 completed subjects, using a worse eye analysis, that the intraocular pressure changed from 18.3+/-2.1 mm Hg on timolol maleate to 18.8+/-2.3 mm Hg on timolol hemihydrate (P=0.10) 12 hours after dosing. There was no difference in the overall incidence of unsolicited anterior segment side effects between timolol maleate (4 cases) versus timolol hemihydrate (3 cases) (P=0.69). One patient exited the study because of pain and burning in both eyes while on timolol maleate. No patient was discontinued due to loss of intraocular pressure control after switching to timolol hemihydrate. It was concluded that switching from timolol maleate to timolol hemihydrate is safe and effective in maintaining control of the intraocular pressure.

Cardiovascular effects of topical carteolol hydrochloride and timolol maleate in patients with ocular hypertension and primary open-angle glaucoma. Night Study Group

PURPOSE

To compare the effects of topical timolol maleate 0.5% and carteolol hydrochloride 1% on pulse rate and blood pressure.

METHODS

In a randomized, double-masked, parallel-design, multicenter clinical trial, we compared the effects of timolol and carteolol on pulse rate and blood pressure measured by 24-hour ambulatory blood pressure monitoring in 169 adult patients with either ocular hypertension or primary open-angle glaucoma.

RESULTS

From noon to 8 PM, baseline mean pulse rate of 82 to 83 beats per minute (bpm) had decreased by 4 to 6 bpm in both groups after 4 weeks of therapy with timolol or carteolol. From midnight to 4 AM, the pulse rate in the carteolol group was significantly above baseline (P = .005), while the timolol group was significantly below baseline (P < .001). Four times as many patients became bradycardic (heart rate, < 60 bpm) on timolol (18.4%) as did patients on carteolol (4.5%) from midnight to 4 AM. More than twice as many patients exhibited a resolution of their bradycardia with carteolol (46.7%) as did patients treated with timolol (18.2%) from midnight to 4 AM. Overall cardiovascular adverse effects were reported significantly more frequently in the timolol than the carteolol group (P = .002).

CONCLUSIONS

Timolol causes significantly lower mean heart rate during the nighttime and more nocturnal bradycardia than carteolol does in patients with ocular hypertension and primary open-angle glaucoma. These differences may be because of the intrinsic sympathomimetic activity of carteolol.