Effect of brinzolamide and dorzolamide on aqueous humor flow in human eyes

Ocular Pharmacokinetic Properties of Intravitreally Injected Aflibercept in Rabbits After Using Brinzolamide/Timolol Eye Drops

Purpose: To investigate the ocular pharmacokinetic properties of intravitreally injected aflibercept in rabbits after using brinzolamide 1%/timolol maleate 0.5% fixed-combination eye drops. Methods: The right eye of 5 rabbits was topically administered 30 μL of brinzolamide and timolol maleate eye drops twice a day (q12h). The 2 eyes of each rabbit were injected with 1.0 mg (0.025 cc) of aflibercept on the 2nd day after instilling the eye drops. The intraocular pressure of the rabbits was measured before injection and sampling. The aqueous humor was drawn at 1, 3, 7, 14, 21, and 28 days. Aflibercept concentrations in aqueous humor and vitreous humor (28 days) were measured by enzyme-linked immunosorbent assay. Results: The aflibercept aqueous concentrations in the right eye at days 7, 14, 21, and 28 after injection were all significantly higher than those in the left eye (P > 0.05, n = 5). The peak aqueous concentrations of aflibercept in right eyes (49.5 μg/mL) and left eyes (50.9 μg/mL) were both observed at 1 day after injection. The elimination half-life of aflibercept in the aqueous humor of the right eye (4.70 days) was 1 day longer than that of the left eye (3.65 days). The average percentage of residual aflibercept in the vitreous humor of the right eye (3.35%) was also significantly higher than that of the left eye (0.63%). Conclusions: Brinzolamide 1%/timolol maleate 0.5% fixed-combination eye drops can significantly extend the ocular residence time of intravitreally injected aflibercept.

Remodeling of the Lamina Cribrosa: Mechanisms and Potential Therapeutic Approaches for Glaucoma

Glaucomatous optic neuropathy is the leading cause of irreversible blindness in the world. The chronic disease is characterized by optic nerve degeneration and vision field loss. The reduction of intraocular pressure remains the only proven glaucoma treatment, but it does not prevent further neurodegeneration. There are three major classes of cells in the human optic nerve head (ONH): lamina cribrosa (LC) cells, glial cells, and scleral fibroblasts. These cells provide support for the LC which is essential to maintain healthy retinal ganglion cell (RGC) axons. All these cells demonstrate responses to glaucomatous conditions through extracellular matrix remodeling. Therefore, investigations into alternative therapies that alter the characteristic remodeling response of the ONH to enhance the survival of RGC axons are prevalent. Understanding major remodeling pathways in the ONH may be key to developing targeted therapies that reduce deleterious remodeling.

Switching the Inhibitor-Enzyme Recognition Profile via Chimeric Carbonic Anhydrase XII

A key part of the optimization of small molecules in pharmaceutical inhibitor development is to vary the molecular design to enhance complementarity of chemical features of the compound with the positioning of amino acids in the active site of a target enzyme. Typically this involves iterations of synthesis, to modify the compound, and biophysical assay, to assess the outcomes. Selective targeting of the anti-cancer carbonic anhydrase isoform XII (CA XII), this process is challenging because the overall fold is very similar across the twelve CA isoforms. To enhance drug development for CA XII we used a reverse engineering approach where mutation of the key six amino acids in the active site of human CA XII into the CA II isoform was performed to provide a protein chimera (chCA XII) which is amenable to structure-based compound optimization. Through determination of structural detail and affinity measurement of the interaction with over 60 compounds we observed that the compounds that bound CA XII more strongly than CA II, switched their preference and bound more strongly to the engineered chimera, chCA XII, based on CA II, but containing the 6 key amino acids from CA XII, behaved as CA XII in its compound recognition profile. The structures of the compounds in the chimeric active site also resembled those determined for complexes with CA XII, hence validating this protein engineering approach in the development of new inhibitors.

Efficacy and Safety of Brinzolamide as Add-On to Prostaglandin Analogues or β-Blocker for Glaucoma and Ocular Hypertension: A Systematic Review and Meta-Analysis

Background: Brinzolamide as a carbonic anhydrase inhibitor could be combined with other intraocular pressure (IOP) lowering drugs for glaucoma and ocular hypertension (OHT), but the efficacy was controversial. So, this study was used to assess the efficacy and safety of brinzolamide as add-on to prostaglandin analogues (PGAs) or β-blocker in treating patients with glaucoma or OHT who fail to adequately control IOP.

Methods: We searched PubMed, Embase, MEDLINE, Cochrane Library, and clinicaltrials.gov from inception to October 4, 2018. Randomized controlled trials of brinzolamide as add-on to PGAs or β-blocker for glaucoma and OHT were included. Meta-analysis was conducted by RevMan 5.3 software.

Results: A total of 26 trials including 5,583 patients were analyzed. Brinzolamide produced absolute reductions of IOP as an adjunctive therapy for patients with glaucoma or OHT. Brinzolamide and timolol were not significantly different in lowering IOP as add-on to PGAs (9 am: P = 0.07; 12 am: P = 0.66; 4 pm: P = 0.66). Likewise, brinzolamide was as effective as dorzolamide in depressing IOP (9 am: P = 0.59; 12 am: P = 0.94; 4 pm: P = 0.95). For the mean diurnal IOP at the end of treatment duration, there were no statistical differences in above comparisons (P > 0.05). Compared with brimonidine (b.i.d.), there was a significant reduction of IOP in brinzolamide (b.i.d.) at 9 am (P < 0.0001); however, the difference was cloudy in thrice daily subgroup (P = 0.44); at 12 am, brinzolamide (b.i.d.) was similar to brimonidine (b.i.d.) in IOP-lowering effect (P = 0.23), whereas brimonidine (t.i.d.) led to a greater effect than brinzolamide (t.i.d.) (P = 0.02). At 4 pm, brinzolamide (b.i.d.) was superior IOP-lowering effect compared with brimonidine (b.i.d.) (P = 0.0003); conversely, the effect in brinzolamide (t.i.d.) was lower than brimonidine (t.i.d.) (P < 0.0001). For the mean diurnal IOP, brinzolamide was lower in twice daily subgroup (P < 0.00001); brimonidine was lower in thrice daily subgroup (P < 0.00001). With regard to the safety, brinzolamide and dorzolamide had a higher incidence of taste abnormality; moreover, brinzolamide resulted in more frequent blurred vision; dorzolamide resulted in more frequent ocular discomfort and eye pain. Timolol resulted in more frequent blurred vision and less conjunctival hyperemia. Brimonidine resulted in more frequent ocular hyperemia. As to other adverse events (AEs) (conjunctivitis, eye pruritus, foreign body sensation in eyes, and treatment-related AEs), brinzolamide was similar to other three active comparators.

Conclusions: Brinzolamide, as add-on to PGAs or β-blocker, significantly decreased IOP of patients with refractory glaucoma or OHT and the AEs were tolerable.

Effect of glaucoma medications on 24-hour intraocular pressure-related patterns using a contact lens sensor

BACKGROUND

The aim of this article was to study the circadian intraocular pressure (IOP)-related effects of ocular hypotensive medications using a contact lens sensor (CLS).

DESIGN

This is a university-based prospective, randomized, crossover trial.

PARTICIPANTS

A total of 23 patients with primary open-angle glaucoma participated.

METHODS

Patients underwent ambulatory recording of IOP-related patterns for 24 h in one eye during 3 monthly sessions using a CLS. Patients were untreated in session 1 (S1), were randomized to one of four classes of glaucoma drops for S2 and had a prostaglandin analogue add-on for S3.

MAIN OUTCOME MEASURES

Changes in IOP-related patterns were defined using (i) slopes from wake/sitting to sleep/supine; (ii) cosinor rhythmometry modelling; and (iii) area under receiver operating curve (AUC) of sleep period.

RESULTS

Mean patient age was 63.8 ± 11.8 years. Positive linear slopes were seen from wake/sitting to sleep/supine at S1 (17.1 ± 14.2 mVeq/h) and S2 (5.5 ± 23.9 mVeq/h) and negative slopes at S3 (-1.9 ± 29.4 mVeq/h) (S1-S2, P = 0.01; S1-S3, P = 0.02). In the prostaglandin group, slopes changed significantly with introduction of drops (S1-S2, P < 0.024), whereas they did not in a mixed group combining the three other classes (S1-S2, P = 0.060). Overall, cosinor amplitudes were 98.4 ± 46.5 mVeq (S1), 113.0 ± 35.6 mVeq (S2) and 109.6 ± 58.3 mVeq (S3) (S1-S2, P = 0.23; S1-S3, P = 0.66; S2-S3, P = 0.93). AUC were 91.8 ± 63.0 mVeq (S1), 76.3 ± 102.7 mVeq (S2) and 19.9 ± 135.8 mVeq (S3). Differences between sessions were not statistically significant (S1-S2, P = 0.541; S1-S3, P = 0.083; S2-S3, P = 0.092).

CONCLUSIONS

Prostaglandin analogues, but not other medications, seem to flatten the IOP-related increase at transition of the wake/sitting to the sleep/supine period, but do not seem to have an effect on acrophase and amplitude.

Synthesis and characterisation of novel Co(II) complexes of pyrazole carboxylate derivated of sulfonamide as carbonic anhydrase inhibitors

OBJECTIVES

Two new metal complexes, diaquabis(4-benzoyl-1,5-diphenyl-N-(5-sulfamoyl-1,3,4-thiadiazol-2-yl)-1H-pyrazole-3-carboxamide)cobalt(II) dihydrate (2) and diaquabis(ethyl-1-(3-nitrophenyl)-5-phenyl-3-(5-sulfamoyl-1,3,4-thiadiazol-2-ylcarbamoyl)-1H-pyrazole-4-carboxylate)cobalt(II) monohydrate (4), containing sulfonamide have been synthesized by the reaction of Co(II) with 4-benzoyl-1,5-diphenyl-N-(5-sulfamoyl-1,3,4-thiadiazol-2-yl)-1H-pyrazole-3-carboxamide (1) and ethyl-1-(3-nitrophenyl)-5-phenyl-3-(5-sulfamoyl-1,3,4-thiadiazol-2-ylcarbamoyl)-1H-pyrazole-4-carboxylate (3), respectively.

METHODS

The structures of Co(II) complexes 2 and 4 have been characterised by spectroscopic methods and elemental analyses. Human carbonic anhydrase isoenzymes (hCA-I and hCA-II) were purified from erythrocyte cells by affinity chromatography. The inhibitory effects of ligands 3 and 4, acetazolamide as a control compound and the newly synthesized complexes on the activity of hydratase and esterase of these isoenzymes have been studied in vitro.

KEY FINDINGS

The concentration of compounds 2 and 4 producing a 50% inhibition of hydratase activity (IC(50) values) were 0.473 ± 0.025 and 0.065 ± 0.002 μm for hCA-I and 0.213 ± 0.015 and 0.833 ± 0.021 μm for hCA-II, respectively. The IC(50) values of synthesized compounds 2 and 4 for esterase activity were, 0.058 ± 0.006 and 0.297 ± 0.015 μm for hCA-I and 0.110 ± 0.010 and 0.052 ± 0.002 μm for hCA-II, respectively. In relation to esterase activity, the inhibition equilibrium constants (K(i) ) were determined as 0.039 ± 0.004 and 0.247 ± 0.035 μm on hCA-I and 0.078 ± 0.002 and 0.363 ± 0.015 μm on hCA-II for 2 and 4, respectively.

CONCLUSIONS

The synthesized compounds 2 and 4 had effective inhibitory activity (P < 0.0001) on hCA-I and hCA-II than the corresponding free ligands, 1 and 3, and acetazolamide. Compounds 2 and 4 might be considered as potential inhibitors.

Brinzolamide ophthalmic suspension: a review of its pharmacology and use in the treatment of open angle glaucoma and ocular hypertension

Brinzolamide is a white powder commercially formulated as a 1% ophthalmic suspension to reduce intraocular pressure (IOP). Pharmacologically, brinzolamide is a highly specific, non-competitive, reversible, and effective inhibitor of carbonic anhydrase II (CA-II), able to suppress formation of aqueous humor in the eye and thus to decrease IOP. Several clinical trials have evaluated its safety and the most commonly ocular adverse events are blurred vision (3%-8%), ocular discomfort (1.8%-5.9%), and eye pain (0.7%-4.0%). Brinzolamide has been introduced to treat ocular hypertension and primary open-angle glaucoma. In some clinical studies it has been estimated that brinzolamide reduced IOP by was about 18%. Brinzolamide can be added to beta-blockers and prostaglandins. In the latter combination, because prostaglandin derivatives improve the uveoscleral outflow but also increase the activity of CA in ciliary epithelium with a secondary increase in aqueous humor secretion, and slightly reduce the efficacy of prostaglandin analogues, theoretically topical CA inhibitors (CAI) decrease IOP by inhibiting CA-II, thus improving prostaglandin efficacy as well as lowering IOP. Brinzolamide could have a secondary possible effect on ocular flow too. Some clinical studies showed a mild improvement of ocular blood flow. Theoretically, CAI could give rise to metabolic acidosis, with secondary vasodilatation and improvement of blood flow. Systemic acidosis can occur in the setting of oral CAI therapy, and local acidosis within ocular tissues is theoretically possible with topical CAI therapy, with the potential for a local increase in ocular blood flow. In conclusion, topical CAI treatment has efficacy in IOP-lowering ranging from 15% to 20%. From published data, brinzolamide can be used as first-line medication, even if other medications have a higher efficacy, with few side effects and it is a good adjunctive treatment. In some type of glaucoma patients with a vascular dysregulation, topical CAI could have a double effect: reducing IOP and improving ocular blood flow.

Synthesis of 5-amino-1,3,4-thiadiazole-2-sulphonamide derivatives and their inhibition effects on human carbonic anhydrase isozymes

In this study, some novel inhibitors were synthesised from the further stage reactions of 4-benzoyl-1-(4-nitrophenyl)-5-phenyl-1H-pyrazole-3-carbonyl chloride with 5-amino-1,3,4-thiadiazole-2-sulphonamide 1 (inhibitor 1). They were characterised by elemental and spectral (¹H NMR, ¹³C NMR, IR) analyses. Human carbonic anhydrase isoenzymes (hCA-I and hCA-II) were purified from erythrocyte cells by affinity chromatography. The inhibitory effects of inhibitor 1, acetazolamide (2) and the 11 newly synthesised amides (8-18) on the hydratase and esterase activities of these isoenzymes (hCA-I and hCA-II) were studied in vitro. In relation to these activities, the inhibition equilibrium constants (K(i)) were determined. The K(i) values for the new compounds (8-18) were observed to be well below that of the parent compound inhibitor 1 and were also compared to 2 under the same experimental conditions. The comparison of the newly synthesised amides to inhibitor 1 and to 2 indicated that the new derivatives preferentially inhibited hCA-II and were more potent inhibitors of hCA-II than the parent inhibitor 1 and 2.

Effects of brinzolamide vs timolol as an adjunctive medication to latanoprost on circadian intraocular pressure control in primary open-angle glaucoma Japanese patients

Purpose

To study the effect of the concomitant use of brinzolamide and latanoprost on the 24-hour variation in intraocular pressure (IOP) in primary open-angle glaucoma (POAG) patients first treated with timolol and latanoprost.

Methods

We studied 30 eyes from 30 POAG patients previously treated with latanoprost monotherapy. After a washout of four weeks in both eyes, all patients were treated with 0.5% timolol and latanoprost. Three months after the initiation of treatment with timolol and latanoprost, the 24-hour IOP variation was measured. Thereafter, all patients were treated with concomitant 1% brinzolamide and latanoprost. Three months after changing the therapeutic regimen, the 24-hour IOP variation was measured a second time. Latanoprost was administered once a day, and timolol and brinzolamide were twice a day. IOP was measured with a noncontact tomometer.

Results

On treatment with brinzolamide and latanoprost, a significant decrease in IOP compared to timolol and latanoprost was observed at all time points except at 3 PM and 6 PM. As a group, the patients had a significantly lower diurnal mean IOP and nocturnal mean IOP during treatment with brinzolamide and latanoprost than with timolol and latanoprost.

Conclusions

Treatment of POAG with a combination of brinzolamide and latanoprost demonstrated improved hypotensive effects compared with timolol and latanoprost during a 24-hour period.

Effects of medications and surgery on intraocular pressure fluctuation

Intraocular pressure (IOP) varies dynamically throughout the circadian cycle. IOP elevations during the nocturnal period may be particularly important in the pathogenesis of glaucoma, although sleeping IOP cannot be measured at this time. Additionally, IOP fluctuations may be an independent risk factor for glaucoma. However, not all glaucoma therapies are equally effective at lowering IOP throughout the 24-hour period. The prostaglandin analogs have excellent IOP control throughout the 24-hour period, although less at night than during the day. In contrast, some other classes of medications, such as the beta-blockers, have little or no IOP-lowering effect at night. The prostaglandin analogs also have excellent persistency of IOP lowering, lasting at least as long as the 24-hour dosing period, and likely much longer. Glaucoma filtering surgery appears to have even better 24-hour IOP reduction and smaller fluctuations than maximal medical therapy including prostaglandin analogs.

[Not Available]

To investigate the effect of brinzolamide on diurnal fluctuations in the intraocular pressure (IOP) in patients on latanoprost ophthalmic solution prospectively was aimed. Eleven patients with primary open angle glaucoma were enrolled in this study. The subjects were admitted to the hospital and had their IOPs measured over 24 hours (10 AM, noon, 2 PM, 4 PM, 6 PM, 8 PM, 10 PM, midnight, 3 AM, 6 AM, and 8AM). After topical administration of brinzolamide twice daily for 4-8 weeks for one eye, they were readmitted and again had their IOPs measured in the same manner as during the previous admission. The additional administration of brinzolamide significantly reduced IOP by 9.7±4.5% during 24-hour, 9.5±4.7% during daytime, and 10.3±5.6% during nighttime, respectively. Brinzolamide exerts additive effects over 24 hours in reducing IOP in patients with glaucoma who are receiving latanoprost ophthalmic solution.

24-hour control of intraocular pressure with 2% dorzolamide/0.5% timolol fixed-combination ophthalmic solution in open-angle glaucoma

OBJECTIVE

To evaluate the 24-hour efficacy and tolerability of 2% dorzolamide/0.5% timolol fixed combination (DTFC) solution in open-angle glaucoma and ocular hypertension.

RESEARCH DESIGN AND METHODS

Randomized, parallel, double-masked, multicenter study. Patients with insufficiently controlled intraocular pressure (IOP > or = 22 mmHg) were randomized to DTFC (N = 117) or timolol (N = 115). IOP was measured at baseline, 6 weeks, and 8 weeks, with measurements taken at 6 p.m., 8 p.m., 10 p.m., 2 a.m., 6 a.m., 8 a.m., 10 a.m., and 2 p.m. ClinicalTrials. gov identifier: NCT00108017 MAIN OUTCOME MEASURES: Statistically significant change in IOP from untreated baseline for DTFC at all hours at week 8. Secondary outcome measures included: IOP-lowering at week 6 at all individual time points, change from baseline to 8 weeks in mean daytime IOP (average of 8 a.m., 10 a.m., 2 p.m., 6 p.m., and 8 p.m. IOPs) and night-time IOP (10 p.m., 2 a.m., 6 a.m.), and comparison of DTFC with timolol after 8 weeks.

RESULTS

Patients receiving DTFC had a statistically significant and clinically relevant reduction in IOP at week 8 compared with baseline at all eight time points (p < 0.001). Significant IOP reductions were also seen at all time points at week 6 (p < 0.001). DTFC significantly lowered mean daytime IOP and night-time IOP ( p < 0.001 for both). Timolol alone also significantly reduced IOP from baseline at 8 weeks for all diurnal time points, and mean daytime and night-time IOP ( p < 0.001 for all). Compared with timolol alone, there were significantly greater reductions with DTFC at 10 a. m. (p = 0.003) and 2 p. m. (p = 0.016), and for mean daytime IOP (p = 0.025) at 8 weeks. Significant between-treatment differences were not observed at other time points. Both treatments were well-tolerated, with no differences observed in the safety profiles between the treatment groups.

CONCLUSIONS

Both DTFC and timolol provided significant IOP reduction over the entire 24-hour measurement period. Although this study was not designed or powered to compare DTFC and timolol, DTFC exhibited greater IOP-lowering than timolol during the daytime, but not at night.

Intraocular pressure-lowering efficacy of brinzolamide 1%/timolol 0.5% fixed combination compared with brinzolamide 1% and timolol 0.5%

PURPOSE

To compare the safety and intraocular pressure (IOP)-lowering efficacy of brinzolamide 1%/timolol 0.5% fixed combination with brinzolamide 1% or timolol 0.5% alone in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT).

DESIGN

Randomized, double-masked, parallel group, multicenter study.

PARTICIPANTS

Five hundred twenty-three patients were randomized to the study treatments.

METHODS

Patients with OAG or OHT were recruited to the study. Qualifying eyes had IOPs of 24 to 36 mmHg at 8 am and 21 to 36 mmHg at 10 am on 2 eligibility visits after an appropriate washout period from previous treatment. Patients were assigned randomly to either brinzolamide 1%/timolol 0.5%, brinzolamide 1% (Azopt; Alcon Laboratories, Fort Worth, TX), or timolol 0.5%, dosed twice daily and were followed up while receiving therapy for 6 months. At selected sites, additional IOP measurements were performed at 12 pm, 4 pm, and 8 pm during the 2 eligibility visits, at month 3, and at month 6.

MAIN OUTCOME MEASURE

Mean IOP.

RESULTS

Brinzolamide 1%/timolol 0.5% produced statistically significant and clinically relevant reductions from baseline ranging from 8.0 to 8.7 mmHg, which were statistically and clinically superior to that of either brinzolamide 1% (5.1-5.6 mmHg) or timolol 0.5% (5.7-6.9 mmHg). No safety concerns were identified based on an assessment of ocular and cardiovascular parameters and a review of adverse events.

CONCLUSIONS

Brinzolamide 1%/timolol 05% is superior in IOP-lowering efficacy to either brinzolamide 1% or timolol 0.5%.

Goniodysgenesis associated with primary glaucoma in an adult European Short-haired cat

A 9.5-year-old, male castrated European Short-haired (ESH) cat was presented with bilateral glaucoma associated with pectinate ligament dysplasia and an open iridocorneal angle (ICA) upon gonioscopy. The right eye (OD) was avisual and slightly enlarged; the left eye (OS) was still visual. Intraocular pressure (IOP) had been controlled with medical therapy over a 1.5 year-period in both eyes (OU). Eventually IOP could not be adequately controlled medically and the painful and blind right eye was enucleated and transscleral diode laser cyclophotocoagulation was performed twice in the left eye with less than optimal results and progressive loss of vision. Histopathology of the right eye showed goniodysgenesis characterized by failure of differentiation of the pectinate ligament, which existed as a solid sheet of uveal tissue at the entrance of a hypoplastic ciliary cleft, which contained loose mucoid mesenchymal tissue. The trabecular meshwork was hypoplastic and the scleral venous plexus could not be identified. Other findings of chronic glaucoma were inner retinal atrophy, optic nerve atrophy with disc cupping, scleral thinning, peripheral corneal vascularization and pigmentation, and mild focal iridal mononuclear inflammatory cell infiltrate.

Effect of Concomitant Use of Latanoprost and Brinzolamide on 24-hour Variation of IOP in Normal-tension Glaucoma

PURPOSE

To study the effect of the concomitant use of latanoprost and brinzolamide on the 24-hour variation in the intraocular pressure (IOP) in patients with normal-tension glaucoma (NTG).

METHODS

We studied a total of 44 eyes from 22 NTG patients. Mean 24-hour IOP variation was determined after a washout period of > or =4 weeks. Latanoprost monotherapy was continued in both eyes for 8 weeks. Thereafter, patients were randomized to continue latanoprost monotherapy in 1 eye whereas brinzolamide was added as an adjunct to latanoprost therapy in the other eye. Eight weeks after the initiation of brinzolamide treatment, the 24-hour IOP variation was remeasured. IOP was measured in the sitting position 8 times daily using a Goldmann applanation tonometer before and after treatment.

RESULTS

The eyes treated with latanoprost monotherapy and those treated with latanoprost and brinzolamide showed a significant decrease in IOP at all time points. Percent reductions in the diurnal mean IOP (mean IOP at 10 AM, 1 PM, and 4 PM) and in nocturnal mean IOP (mean IOP at 10 PM, 1 AM, and 3 AM) were significantly greater in the eyes treated with the combination of latanoprost and brinzolamide than those with latanoprost alone (diurnal mean IOP: latanoprost and brinzolamide=19.8%, latanoprost=14.1%, P<0.001; nocturnal mean IOP: latanoprost and brinzolamide=13.4%, latanoprost=10.0%, P<0.05).

CONCLUSIONS

For the treatment of NTG, the combination of latanoprost and brinzolamide demonstrated additive effects in lowering IOP, not only during the day, but also at night.

Effect of Laser Trabeculoplasty on Nocturnal Intraocular Pressure in Medically Treated Glaucoma Patients

PURPOSE

To evaluate the effects of laser trabeculoplasty on 24-hour intraocular pressure (IOP) in a group of medically treated open-angle glaucoma patients.

DESIGN

Prospective experimental study.

PARTICIPANTS

Eighteen open-angle glaucoma patients.

METHODS

Laser trabeculoplasty (180 degrees ) was performed on 28 eyes of 18 glaucoma patients. Twenty-four-hour IOP data were collected in a sleep laboratory before and 45 to 80 days after the procedure. Measurements of sitting and supine IOP were taken during the 16-hour diurnal/wake period, and measurements of supine IOP were taken during the 8-hour nocturnal/sleep period in 2-hour intervals.

MAIN OUTCOME MEASURES

Changes in the mean, peak, and range of IOP during the office-hour, diurnal, nocturnal, and 24-hour periods.

RESULTS

Compared with the baselines, changes in the mean, peak, and range of IOP were not significant during the office-hour period and during the diurnal period in either the sitting or the supine position. The mean, peak, and range of IOP were reduced significantly during the nocturnal period in the supine position. Mean and peak 24-hour IOP were reduced significantly in the habitual body positions (sitting during the diurnal period and supine during the nocturnal period). The reduction of mean 24-hour IOP in the supine position also was significant.

CONCLUSIONS

In this group of medically treated open-angle glaucoma patients, laser trabeculoplasty reduced IOP more consistently during the nocturnal period than during the diurnal period.

Variations nycthémérales de la pression intraoculaire et leurs implications cliniques

Intraocular pressure follows a circadian rhythm like many of the body's parameters. These fluctuations in intraocular pressure were recently identified as a risk factor for visual field loss, in addition to intraocular pressure itself. Furthermore, the pressure curve seems to have a different profile in glaucomatous patients: the peak occurs later compared with normal subjects. Better knowledge of pressure fluctuations and their physiological mechanisms is essential for optimal management of glaucomatous patients not only to interpret the single ocular tension recordings, but also to use the available treatments rationally, both drugs and surgery. The authors review different studies that have contributed to the current knowledge on the circadian rhythm of intraocular pressure, aquous humor flow regulation, and the effects of topical hypotensive drugs on the pressure curve.

Advances in glaucoma therapeutics

Glaucoma is a major cause of irreversible blindness in the world. The prevalence of glaucomatous loss in vision will continue to grow as our populations age. Ocular hypertension is a major risk factor for the development of glaucoma and current glaucoma therapy is directed at lowering intraocular pressure. Several new ocular hypotensive agents have been introduced in the past several years providing a variety of treatment options. In addition, various classes of neuroprotective agents demonstrating activity in a wide variety of animal models have been proposed as potential new glaucoma therapeutics. Although these approaches will slow the progression of vision loss, they do not directly intervene in the disease process(es). Advances have been made attempting to understand the pathogenic pathways involved in glaucomatous damage to the eye and in methods to clinically measure glaucoma damage. An increased understanding of the pathophysiology of glaucoma will lead to the development of new therapeutic agents that intervene and perhaps even reverse glaucomatous damage to the eye. There also is a need to develop new methods to clinically measure glaucoma damage because, currently, considerable damage occurs before glaucoma is diagnosed and glaucoma remains underdiagnosed in the general population.

Concomitant administration of travoprost and brinzolamide versus fixed latanoprost/timolol combined therapy: three-month comparison of efficacy and safety

PURPOSE

To compare the efficacy and safety of the concomitant administration of travoprost 0.004% once daily and brinzolamide 0.1% twice daily with those of a fixed combination of latanoprost 0.005%/timolol 0.5% once daily.

RESEARCH, DESIGN AND METHODS

Forty-four patients with primary open-angle glaucoma or ocular hypertension with elevated IOP insufficiently responsive to monotherapy were randomly assigned to one of the two treatment groups: concomitant administration of travoprost 0.004% once daily and brinzolamide 0.1% twice daily (TB group: 22 patients) or latanoprost 0.005% plus timolol 0.5% once daily (LT group: 22 patients). Visits were undertaken at screening (current ocular hypotensive therapy was discontinued), baseline (randomization), and after 2 weeks, 1 month, 2 months and 3 months of therapy.

MAIN OUTCOME MEASURES

IOP was determined at 9 a.m., 12 p.m. and 4 p.m. at each study visit, and diurnal IOP was calculated as the mean of these recordings. Adverse events were recorded at each visit.

RESULTS

IOP at the baseline visit was similar in both groups. Overall mean IOP was significantly lower in the TB as compared to the LT group after 1 month, 2 month and 3 month follow-up; only 9 a.m. measurements were significantly different, reaching a maximum difference (16.9 +/- 0.9 mmHg vs 18.4 +/- 1.8 mmHg, p < 0.001) at the 3 month check. The percentage of responders (IOP decrease > or = 30%) was higher in the TB group. Both treatments were well tolerated and there were no cases of withdrawal from treatment.

CONCLUSIONS

Travoprost 0.004% and brinzolamide 0.1% concomitant therapy showed a greater efficacy than the fixed latanoprost 0.005%/timolol 0.5% combination in terms of absolute IOP decreases. Travoprost/brinzolamide therapy also offered the advantages of a greater percentage of responders.

Comparing the effects of travoprost and brinzolamide on intraocular pressure after phacoemulsification

PURPOSE

To evaluate the intraocular pressure (IOP) lowering effect of travoprost and brinzolamide within the first 24 h after phacoemulsification cataract surgery.

METHODS

This prospective, randomized, double-masked, controlled study comprised 90 eyes of 90 consecutive patients with senile cataract who had uneventful phacoemulsification surgery. Eyes in the first group received travoprost 0.0015%, second group received brinzolamide 1%. Eyes in the third group received balanced salt solution and were used as control. One drop was instilled immediately after surgery. IOP was measured 24 h preoperatively, 6 and 24 h postoperatively. Analysis of variance, Student's-t and chi2-tests were used for statistical analyses.

RESULTS

Preoperatively IOP was not significantly different among the three groups (P = 0.653). At 6 and 24 h postoperatively IOP was lower in both travoprost and brinzolamide group when compared to control group (P = 0.018 and 0.015 at 6 h, P = 0.010 and 0.007 at 24 h between travoprost and brinzolamide group was not significant (P = 0.744 at 6 h and P = 0.672 at 24 h).

CONCLUSION

Both travoprost and brinzolamide significantly lowered IOP after small incision phacoemulsification cataract surgery within the first 24 h without any side effect.

Effects on Aqueous Flow of Dorzolamide Combined with Either Timolol or Acetazolamide

PURPOSE

To determine the effect on aqueous flow of topical dorzolamide 2%, topical timolol 0.5%, or oral acetazolamide 250 mg when used alone or when dorzolamide is combined with either timolol or acetazolamide.

METHODS

In 30 patients with ocular hypertension, aqueous flow and intraocular pressure (IOP) were determined at baseline and on the following combinations of drugs in a crossover design: (1) vehicle alone, (2) dorzolamide alone, (3) acetazolamide alone, (4) timolol alone, (5) dorzolamide + acetazolamide, and (6) dorzolamide + timolol. Treated eyes were compared with control eyes and comparisons were made between treatments.

RESULTS

Compared with baseline, significant (P < 0.04) IOP reductions in the order of efficacy were: dorzolamide + timolol > dorzolamide + acetazolamide = acetazolamide = timolol > dorzolamide. Aqueous flow was reduced more by dorzolamide + timolol than by each drug alone (P < 0.04) and more by dorzolamide + acetazolamide than by dorzolamide alone (P < 0.04).

CONCLUSION

The combination of dorzolamide and timolol demonstrated significant aqueous flow additivity and had greater IOP efficacy than the combination of dorzolamide and acetazolamide.

Effects of brinzolamide on ocular haemodynamics in healthy volunteers

AIM

A prospective, randomised study to evaluate effects of brinzolamide on ocular haemodynamics in healthy volunteers.

METHODS

30 volunteers (12 men, 18 women; 28.3 (SD 7.8) years) were prospectively randomised to either brinzolamide or placebo during a 2 week double masked treatment trial. Examinations were performed at baseline and after 2 weeks of treatment. Intraocular pressure was measured and automatic static perimetry (Humphrey field analyser, 24-2) and contrast sensitivity (CSV 1000, Vector Vision) were performed. Retrobulbar blood flow velocities (peak systolic and end diastolic velocity) and resistive indices (RI) of ophthalmic artery, central retinal artery and of temporal and nasal short posterior ciliary arteries were measured by colour Doppler imaging (Sonoline Sienna Siemens). In video fluorescein angiograms (scanning laser ophthalmoscope, Rodenstock) arteriovenous passage time (AVP, dilution curves) and peripapillary diameters of retinal arterioles and venules were measured by means of digital image analysis.

RESULTS

Intraocular pressure was significantly decreased by brinzolamide (p<0.0001). Neither brinzolamide nor placebo changed visual field global indices after treatment. Contrast sensitivity at 3 cycles per degree was significantly higher in the placebo group (p<0.05). Apart from an increase of RI in ophthalmic artery under placebo treatment (p<0.05) there was no effect in retrobulbar haemodynamics in both groups. Brinzolamide therapy alone resulted in a significant reduction of AVP compared to baseline (p<0.05), while peripapillary retinal vessels diameters remained unaffected.

CONCLUSIONS

Apart from the expected decrease of intraocular pressure brinzolamide showed no significant change in retrobulbar haemodynamics, but a significant shortening of AVP. Since in glaucoma AVP is prolonged indicating vascular dysfunction this effect might be beneficial in glaucoma therapy.

Effects of topical administration of 1% brinzolamide on normal cat eyes

OBJECTIVE

To evaluate the effect of short-term daily topical administration of 1% brinzolamide on the intraocular pressure (IOP) of healthy domestic cats with normotensive eyes and to assess the potential for negative side effects of drug administration.

ANIMALS

Twelve privately owned adult domestic cats without physical or ocular abnormalities.

PROCEDURE

Normal variation in IOP was determined on day 1. Cats were then treated on days 2-8 with a topical placebo (artificial tear solution) OU q 12 h. On days 9-15 the cats were treated q 12 h with 1% brinzolamide in one randomly selected eye and the placebo in the contralateral eye. All medications (drug and placebo) were administered twice daily at 7 a.m. and 7 p.m. On days 16-22 the cats received no topical medications. IOP, horizontal pupil size in mm and assessment of conjunctival hyperemia were noted OU on days 1, 8, 15 and 22 at 5 time points (9 a.m., 11 a.m., 1 p.m., 3 p.m. and 5 p.m.). Mixed linear regression models were used to compare the IOP of each eye at all time periods for each cat, controlling for age and weight.

RESULTS

Mean IOP was not significantly altered in any eye at any time point during the treatment period compared with pretreatment, baseline, or follow-up evaluations. Conjunctival hyperemia and miosis were not detected in either eye at any time point. Conclusions and clinical relevance Short-term q 12 h administration of 1% brinzolamide did not significantly reduce IOP in this small sample population of normotensive cats under these study conditions. No clinically relevant side effects were noted with brinzolamide administration.

Effects of Brinzolamide on Aqueous Humor Dynamics in Monkeys and Rabbits

This study examines the mechanisms by which brinzolamide reduces intraocular pressure (IOP) in healthy rabbits and in monkeys with unilateral ocular hypertension. Intraocular pressures were measured by pneumatonometry and aqueous flow was determined by fluorophotometry before and after three twice-daily drops of 1% brinzolamide to both eyes per monkey and after similar treatment to one eye per rabbit. In monkeys, outflow facility was determined by fluorophotometry and uveoscleral outflow was calculated. In rabbits, outflow facility was determined by two-level constant pressure infusion and uveoscleral outflow was measured by an intracameral tracer technique. Compared with contralateral vehicle-treated rabbit eyes, IOP was reduced in brinzolamide-treated eyes by 2.5 +/- 1.9 mmHg (mean +/- standard deviation; p =.006) at four hours after the second dose. Aqueous flow was reduced by 0.50 +/- 0.65 microl/min (p =.02). This effect was found in rabbits previously treated with brinzolamide but not in naive rabbits. Treated hypertensive eyes of monkeys had a reduction in IOP of 7.3 +/- 8.8 mmHg (p = 0.01) and aqueous flow of 0.69 +/- 1.10 microL/min (p = 0.05) when compared with baseline. Brinzolamide did not affect outflow facility or uveoscleral outflow in either rabbits or monkeys. It is concluded that, in normotensive eyes of rabbits and hypertensive eyes of monkeys, brinzolamide reduces IOP by reducing aqueous flow and not by affecting aqueous humor drainage.

The effect of latanoprost on circadian intraocular pressure

The presence of a circadian variation of both intraocular pressure (IOP) and aqueous humor flow has been demonstrated in several studies. It must therefore be considered important to monitor IOP and evaluate the efficacy of ocular hypotensive drugs over the 24 hours of the day. The efficacy of latanoprost on IOP during both day and night has been evaluated and the most important results from four such studies are reviewed. The studies reviewed here clearly demonstrate that topical administration of latanoprost 0.005% once daily provided a steady reduction of the IOP during both day and night. Given as a single dose to healthy volunteers, latanoprost resulted in a sustained effect with a significant IOP reduction over 24 hours, and the reduction was still present, however less pronounced, even after 48 hours. Latanoprost administered once daily for 4 weeks to patients with glaucoma or ocular hypertension was more effective in reducing the IOP over 24 hours than timolol gel solution 0.5% once daily, timolol aqueous solution 0.5% twice daily, or dorzolamide 2% three times daily. Latanoprost applied once daily thus provided a better effect on the IOP together with a stable and sustained IOP reduction during both day and night.

New glaucoma medications in the geriatric population: efficacy and safety

Glaucoma can be considered a disease of the aging eye. Most medications used to treat glaucoma are in topical eyedrop form and may cause numerous untoward systemic effects in older persons. In recent years, several new ocular hypotensive medications have become available. These medications are being used more commonly because there is a growing trend by ophthalmologists to aggressively lower intraocular pressure. Therefore, geriatricians require a comprehensive knowledge of medications used to treat glaucoma, in addition to an understanding of their mechanism of action profiles of untoward effects and possible interactions with other diseases or medications. Therefore, we performed a review of the medications recently introduced into clinical practice. We selected drugs approved by the U.S. Food and Drug Administration between 1996 and September 2001. The safety profiles of these agents and their untoward side effects were reviewed by class: topical carbonic anhydrase inhibitors (brinzolamide: ocular tolerance, taste perversion), beta-adrenoceptor antagonists (timolol: bradycardia and bronchospasm), alpha-adrenergic agonists (brimonidine: oral dryness, headache, and fatigue), and prostaglandin analogs (latanoprost, bimatoprost, travoprost, and unoprostone isopropyl: ocular hyperemia, iris color changes). The function of this review is to make geriatricians more aware of the efficacy and untoward effects of medications recently introduced into clinical practice. We recommend that geriatricians perform a medication review on all medications their patients use, including eye drops.

Mechanism of action of bimatoprost (Lumigan)

Bimatoprost is a new ocular hypotensive agent that lowers intraocular pressure (IOP) in normal, ocular hypertensive, and glaucomatous eyes. Its mechanism of action has been studied in normal human subjects. Bimatoprost mildly stimulates the rate of aqueous humor flow during the day (13%) and at night (14%). Its ocular hypotensive action is due primarily to a 26% reduction in the tonographic resistance to outflow. Thus, bimatoprost enhances the pressure-sensitive outflow pathway. Additional beneficial effects may include an increase in the rate of flow via the pressure-insensitive outflow pathway (sometimes called the "uveoscleral outflow pathway") and a lowering of the extraocular recipient pressure (sometimes called "episcleral venous pressure"). Reduction of tonographic resistance to aqueous humor outflow reduces steady-state IOP, an effect that is beneficial for the treatment of glaucoma. In addition to its effect on steady-state IOP, reduction of resistance allows the eye to recover more quickly from transient IOP elevations. The former effect is common to all ocular hypotensive drugs, but the latter effect is an exclusive property of drugs that reduce outflow resistance, such as bimatoprost.

Dorzolamide-induced immune thrombocytopenia: a case report and literature review

PURPOSE

To report a severe case of dorzolamide-induced immune thrombocytopenia, to review the literature on this topic, and to draw attention to the serious potential side effects of this topical sulfonamide.

CASE REPORT

An 83-year-old man with primary open-angle glaucoma in both eyes who was taking topical dorzolamide therapy for 3.5 years developed a severe thrombocytopenia (10,000 platelets/microL). The amount of platelets was not influenced by prednisone therapy but increased rapidly to 100,000/microL after the withdrawal of dorzolamide.

LITERATURE REVIEW

Although the potential capacity of sulfonamides to induce thrombocytopenia is well known, no case of dorzolamide-induced immune thrombocytopenia was published in the medical literature until July 2000.

CONCLUSION

Considering the possible severe side effects that can be induced by topical dorzolamide 2%, ophthalmologists should carefully evaluate during the medical history of their patients the risk of sensitivity to sulfonamides.

Update on topical carbonic anhydrase inhibitors

Topical carbonic anhydrase inhibitors are a novel addition to the armamentarium of medical glaucoma treatment; dorzolamide has been available since 1995 and brinzolamide since 1998. They lower intraocular pressure by inhibiting carbonic anhydrase, a key enzyme for aqueous humor formation. Intraocular pressure-lowering activity of the substances appears to be the same and is similar to that of most other agents, but it does not reach the activity of the unselective beta-blocker timolol or the prostaglandin latanoprost. On concomitant treatment, additivity is reached with all other topical agents. A possible improvement of blood flow may offer an additional benefit, but its significance for the long-term outcome for human glaucoma remains to be shown. Side effects are mostly local. A more physiologic pH of brinzolamide appears to be advantageous.

Pharmaceutical management of the childhood glaucomas

Glaucoma in childhood is a diverse, blinding group of conditions, which presents a major therapeutic challenge. Treatment is primarily surgical with medical treatments used as an adjunct. None of these drugs has been granted approval by the regulatory agencies for use in children, but they are used on a compassionate basis. Issues of efficacy and safety of these medications in children are discussed. beta-adrenoceptor blockers have been employed as first line pharmaceutical therapy for many years. Recently three new classes of drugs have been developed for use in glaucoma in adults. beta-blockers remain first line therapy if there are no contraindications such as asthma. Topical carbonic anhydrase inhibitors (CAI) appear to be less effective than beta-blockers, but seem safe systemically, although associated with local irritation. They are useful as an adjunct to beta-blockers or as first line therapy when beta-blockers are contraindicated. Prostaglandins have not proved as effective in childhood glaucoma as in adult glaucoma, although it works well in some patients with juvenile open angle glaucoma (JOAG) and others with aphakic glaucoma. alpha-adrenergic agonists, although effective at least in the short-term, have serious, potential systemic side effects, which demand close observation when used in neonates and young infants.

Comparison of the efficacy of betaxolol-brinzolamide and timolol-dorzolamide as suppressors of aqueous humor flow in human subjects

OBJECTIVE

To compare the efficacy of combinations of betaxolol-brinzolamide and timolol-dorzolamide as suppressors of aqueous humor flow and ocular hypotensive agents.

DESIGN

Placebo-controlled, masked comparison of the two drug combinations.

PARTICIPANTS

Twenty-five normal human volunteers with the fellow eye serving as control. METHODS OR TESTING: Fluorophotometric measurement of aqueous humor flow and pneumatonometric measurement of intraocular pressure.

MAIN OUTCOME MEASURES

Aqueous humor flow and intraocular pressure.

RESULTS

The betaxolol-brinzolamide combination lowered aqueous flow 39% to 44%, and the timololdorzolamide combination lowered aqueous flow 51%. The betaxolol-brinzolamide combination lowered intraocular pressure 14% to 19%, and the timolol-dorzolamide combination lowered it 18% to 24%.

CONCLUSIONS

Both drug combinations were effective; the timolol-dorzolamide combination appeared to be the more effective of the two after short-term exposure (24 hours).