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Latanoprost treatment for glaucoma: effects of treating for 1 year and of switching from timolol. United States Latanoprost Study Group.

PURPOSE: To determine the efficacy and safety of latanoprost treatment for 1 year in glaucoma patients, and to evaluate the effects of switching from timolol to latanoprost therapy. METHODS: Latanoprost 0.005% was topically applied once daily without masking for 6 months in 223 patients with elevated intraocular pressure after previous treatment with latanoprost once daily or 0.5% timolol twice daily for 6 months in a multicenter, randomized, double-masked, parallel group study. RESULTS: Compared with baseline values before treatment, a significant (P < .0001) diurnal reduction in intraocular pressure of 6 to 8 mm Hg was maintained with minimal fluctuation for the duration of treatment. When treatment was switched from timolol to latanoprost, intraocular pressure was reduced by 1.5 +/- 0.3 mm Hg (mean +/- SEM; 8% change in intraocular pressure; 31% of the intraocular pressure reduction produced by timolol; P < .001) compared with the change in intraocular pressure in patients remaining on latanoprost therapy. Of the patients initially enrolled, 95% successfully completed treatment. There was a slight overall increase in conjunctival hyperemia in patients who switched from timolol to latanoprost, but no change in those who continued latanoprost. The timolol-induced reduction of resting heart rate returned to baseline levels after switching to latanoprost. Of the 247 patients treated with latanoprost during the masked and/or open-label studies, 12 (5%) demonstrated a definite (n = 4) or possible (n = 8) increase in iris pigmentation. CONCLUSIONS: Latanoprost is a well-tolerated ocular hypotensive agent that appears to be more effective than timolol in reducing intraocular pressure. The increase in iris pigmentation appears to be harmless but requires further investigation.

Adult↗

Relative effectiveness of prodrug and viscous solution approaches in maximizing the ratio of ocular to systemic absorption of topically applied timolol.

The effectiveness of the prodrug approach in maximizing the ratio of ocular to systemic absorption of topically applied timolol was compared with that based on viscous solutions. The pigmented rabbit was the experimental animal. o-Butyryl timolol, a lipophilic ester prodrug of timolol, was found to be twice as effective as hyaluronic acid and poly(vinyl alcohol) solutions in enhancing the ocular absorption of timolol. In addition, it was slightly more effective than retaining the instilled dose in the conjunctival sac for 240 min via nasolacrimal blockade. On the other hand, due to its inability to minimize contact of the instilled dose with the nasal mucosa, o-butyryl timolol was less capable than the viscous solutions in reducing systemic drug absorption. But this could be corrected by reducing the instilled solution volume from 25- to 5 microliter, resulting in a nine-fold reduction in plasma timolol levels while still providing the same amount of drug in the aqueous humor as a five times higher dose of timolol. The net result was a 15-fold improvement in the ratio of ocular to systemic drug absorption, which was also achieved upon retaining the instilled dose in the conjunctival sac for 240 min. It thus appears that the approach based on improved corneal absorption would be as effective as that based on improved retention in the conjunctival sac in maximizing the ratio of ocular to systemic drug absorption, so long as a smaller instilled dose volume of the prodrug is used.

Administration, Topical↗

Latanoprost versus combined timolol and dorzolamide.

We reviewed available data comparing latanoprost and combined timolol and dorzolamide and the additive effect of latanoprost in patients receiving timolol and dorzolamide in combination using a literature search through the electronic Medline database and presentations from proceedings of recent glaucoma meetings. Several studies have shown that the intraocular pressure (IOP)-lowering effect of latanoprost once a day is equivalent to timolol 0.5% twice a day and concomitant or combined dorzolamide 2% twice a day. Adding latanoprost to timolol and dorzolamide leads to a further 16% reduction of IOP. We conclude that the effect on IOP reduction of latanoprost is similar to combined timolol and dorzolamide, and the additive effect of latanoprost to a combination of timolol and dorzolamide is clinically relevant. In most cases, the overall safety profile of latanoprost is better than combined timolol and dorzolamide.

Adrenergic beta-Antagonists↗

The nature of backbone monomers determines the performance of imprinted soft contact lenses as timolol drug delivery systems.

The influence of the composition of soft contact lenses on the achievement of a significant increase in drug loading and control release capability was evaluated. Four types of timolol imprinted lenses were prepared by UV irradiation of N,N-diethylacrylamide (DEAA), 2-hydroxyethylmethacrylate (HEMA), 1-(tristrimethyl-siloxysilylpropyl)-methacrylate (SiMA) and N,N-dimethylacrylamide (DMAA) (50:50 v/v), or methylmethacrylate (MMA) and DMAA (50:50 v/v) solutions, to which functional monomer, methacrylic acid (MAA, 100 mM), cross-linker, ethyleneglycol dimethacrylate (EGDMA, 140 mM), and timolol maleate (25 mM) were previously added. Non-imprinted systems were synthesized in the same way but with the omission of timolol. Timolol did not interfere in the polymerization process and all lenses were optically clear and, once wet, showed adequate mechanical properties; nevertheless, the lenses significantly differed in temperature of glass transition (estimated by differential scanning calorimetry and oscillatory rheometry), equilibrium water content and drug loading and release properties. Regarding timolol overall affinity (SK), estimated after fitting the Langmuir equation to the adsorption isotherms obtained in water at 37 degrees C, the lenses ranked in the order HEMA>SiMA-DMAA>MMA-DMAA>DEAA. The highest imprinting effect, i.e. the greatest relative increase in overall affinity (SK) respect to non-imprinted systems, was obtained for the last two systems. These results are explained by interaction capability with timolol, conformational features and hydrophilic character of the lenses. Although all lenses (imprinted and non-imprinted) showed sustained release in 0.9% NaCl solution, the values of diffusion coefficients confirmed that timolol molecules move out easily from hydrophilic networks that present low affinity for the drug; i.e. MMA-DMAA and SiMA-DMAA lenses. The results obtained indicate that modulating the composition of the lenses it is possible to adapt the drug loading and release behavior of the lenses to the treatment requirements of specific pathological processes.

Adsorption↗

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

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

Adrenergic beta-Antagonists↗

Intraocular pressure over 24 hours after repeated administration of latanoprost 0.005% or timolol gel-forming solution 0.5% in patients with ocular hypertension.

PURPOSE: To compare the effect on intraocular pressure (IOP) over 24 hours after 4 weeks of treatment with latanoprost 0.005% and timolol gel 0.5%. DESIGN: Randomized, open, crossover single-center study. PARTICIPANTS: Twenty-seven patients with ocular hypertension. METHODS: The patients were randomly assigned to 4 weeks of latanoprost 0.005% once daily or timolol gel 0.5% once daily, with a 4-week washout period before switching therapy. MAIN OUTCOME MEASURES: Measurement of IOP during 24 hours of hospitalization. Blood pressure and heart rate were also measured repeatedly over the 24 hours. Daytime mean IOP, nighttime mean IOP, and 24-hour mean IOP were calculated as IOP area under the curve (AUC) divided by time in hours. RESULTS: The mean IOP during daytime (7 AM to 10 PM) was 13.5 +/- 0.4 mmHg (daytime IOP, AUC/15 hours, least square mean +/- standard error of the mean [SEM]) in the latanoprost group, and 14.8 +/- 0.4 mmHg in the timolol gel group. This difference of 1.3 +/- 0.3 mmHg was statistically significant in favor of latanoprost (P < 0.001; 95% confidence interval [CI], 0.7, 2.0). The mean IOP at night (10 PM to 7 AM) was 13.7 +/- 0.4 mmHg for latanoprost (nighttime IOP, AUC/9 hours, least square mean +/- SEM) and 15.9 +/- 0.5 mmHg for timolol gel, with a difference of 2.2 +/- 0.3 mmHg (P < 0.001; 95% CI, 1.5, 2.8). At every measured time point during the 24 hours, latanoprost reduced IOP more than timolol. There was no difference between the two treatment groups regarding blood pressure and heart rate. CONCLUSIONS: Latanoprost reduced mean 24-hour IOP, mean daytime IOP, and mean nighttime IOP statistically significantly more than timolol. Also, latanoprost reduced IOP more effectively at every measured time point over the 24 hours compared with timolol gel.

Aged↗

A long-term clinical trial of timolol therapy versus no treatment in the management of glaucoma suspects.

One hundred seven patients with intraocular pressures (IOPs) between 22 and 28 mmHg with normal visual fields on Goldmann perimetry and without evidence of optic nerve damage were randomly assigned to either a timolol treatment (TT) or a no treatment (NT) arm in a prospective clinical trial. The patients were followed for an average of 56 and 51 months, respectively. Criteria for failure were a confirmed IOP of greater than 32 mmHg, stereophotographically documented optic nerve progression, or development of glaucomatous visual field loss by Goldmann or Octopus perimetry. Nine patients failed in the TT group and 17 in the NT group (P = 0.07). Of the nine TT group failures, six had discontinued timolol before failure (4 for greater than 6 months). In a Cox proportional hazards analysis controlling for confounding variables, timolol was found to be significantly protective with an adjusted risk ratio of 0.38 (95% confidence interval = 0.16-0.89, P = 0.03). When only field and disc failure criteria were considered, timolol treatment was found to be significantly protective in an analysis considering patients who stopped timolol as being lost to follow-up (P = 0.05). A higher tonographic facility of outflow was protective in all analyses. A trend toward a substantial loss of effectiveness of timolol on IOP was not observed. Seasonal fluctuations in IOP were observed (P = 0.0007), with higher IOP occurring in the winter. The results demonstrate a favorable influence of timolol therapy on the clinical course of patients with mildly elevated IOP.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Trials as Topic↗

A six-month, randomized, double-masked study comparing latanoprost with timolol in open-angle glaucoma and ocular hypertension. The Latanoprost Study Group.

PURPOSE: To compare the intraocular pressure (IOP)-reducing effect and side effects of 0.005% latanoprost administered once daily with 0.5% timolol administered twice daily in patients with open-angle glaucoma or ocular hypertension. METHODS: This was a randomized, double-masked study with two parallel groups and a treatment period of 6 months. The primary objective of the study is to compare the IOP-reducing effect of lantanoprost with that of timolol at the end of the 6-month treatment period. A total of 294 patients were included: 149 were in the latanoprost group and 145 were in timolol group. Latanoprost was administered in the evening. RESULTS: Diurnal IOP (9:00 am, 1:00 pm, 5:00 pm) was reduced from 25.2 to 16.7 mmHg (33.7%) with lantanoprost and from 25.4 to 17.1 mmHg (32.7%) with timolol as determined at the end of the 6-month treatment period. No upward drift in IOP occurred with either drug during the treatment period. Latanoprost caused a somewhat more conjunctival hyperemia than timolol and more corneal punctuate epithelial erosions. However, both drugs were generally well tolerated. The most significant side effect of latanoprost was increased pigmentation of the iris which was observed in 15 patients (10.1%). Timolol caused more systemic side effects than latanoprost. CONCLUSIONS: Latanoprost 0.005% administered once daily in the evening reduced IOP at least as well as timolol 0.5% administered twice daily. Latanoprost was generally well tolerated systemically and in the eye. However, the drug has an unusual side effect of increasing the pigmentation of the iris, particularly in individuals with green-brown or blue-brown eyes.

Adrenergic beta-Antagonists↗

A comparison of dorzolamide and timolol in patients with pseudoexfoliation and glaucoma or ocular hypertension.

PURPOSE: The purpose of the study is to compare the efficacy and safety profile of 2.0% dorzolamide (three times daily) and 0.5% timolol (twice daily) for up to 6 months in patients with glaucoma or ocular hypertension associated with pseudoexfoliation. The additive effects of dorzolamide and timolol in patients requiring add-on therapy also was evaluated. METHODS: This was a double-masked, randomized, parallel comparison study at 15 Scandinavian sites. One hundred eighty-four patients with pseudoexfoliation and either glaucoma or ocular hypertension who were 21 to 85 years of age were studied. The treatment groups were 2.0% dorzolamide three times daily and 0.5% timolol maleate twice daily. RESULTS: At 6 months, the mean percent reduction in intraocular pressure of 2% dorzolamide and 0.5% timolol was 24% and 29%, respectively, at morning peak and 21% and 23%, respectively, at afternoon trough. The additional intraocular pressure-lowering effect of adding 2.0% dorzolamide twice daily to patients receiving timolol was 14% and 15%, at peak and trough, respectively. There were no differences between treatment groups in the incidence of clinical adverse experiences, and dorzolamide was not associated with the systemic adverse effects typically ascribed to the use of oral carbonic anhydrase inhibitors. CONCLUSION: Two percent dorzolamide (three times daily) was effective and well tolerated in patients with glaucoma or ocular hypertension associated with pseudoexfoliation over the course of 6 months; 0.5% timolol (twice daily) had a greater level of intraocular pressure-lowering activity than did dorzolamide, although the difference between the two treatments became less pronounced during the study period. Finally, 2.0% dorzolamide (twice daily) produced additional lowering of intraocular pressure when given with 0.5% timolol (twice daily).

Adrenergic beta-Antagonists↗

Timolol uptake and release by imprinted soft contact lenses made of N,N-diethylacrylamide and methacrylic acid.

The aim of this work was to evaluate the utility of molecular imprinting for improving the loading capability of weakly cross-linked hydrogels, with a view to their use as soft contact lenses for administration of timolol. Imprinted hydrogels were prepared considering preformation of complexes between methacrylic acid (functional monomers) and timolol (target molecules), and polymerization with N,N-diethylacrylamide and ethylenglycol dimethacrylate (EGDMA, cross-linker) after injection in moulds (0.3 mm thickness) and UV irradiation at room temperature. After polymerization, timolol molecules were removed by washing. When the gels were immersed in timolol solutions, the imprinted gels adsorbed much more timolol than the corresponding non-imprinted ones, especially above 60 mM EGDMA. The minimum cross-linker concentration for the imprinting to be effective was 80 mM EGDMA. The imprinted contact lenses improved significantly the affinity of the hydrogels for timolol, estimated after fitting Langmuir equation to the adsorption isotherms. These results indicated that adsorption sites capable of capturing the target molecules were encoded effectively into the polymer network by the molecular imprinting technique and, in consequence, improved the drug loading capacity of the gels. Loaded imprinted contact lenses were able to prolong timolol release, in 0.9% NaCl aqueous solution, for more than 24 h.

Acrylamide↗

Short-term effect of latanoprost and timolol eye drops on tear fluid and the ocular surface in patients with primary open-angle glaucoma and ocular hypertension.

PURPOSE: To investigate and compare the short term effects of topical latanoprost and timolol on the tear fluid and ocular surface condition in patients with bilateral primary open angle glaucoma or ocular hypertension. METHODS: Thirty-seven patients were included in this randomized, double-masked, parallel group study. Patients received either latanoprost 0.005% (n= 18) or timolol 0.5% (n= 19) instilled once daily in the morning for a treatment period of 27 days. Routine ophthalmic examinations, including intraocular pressure measurement, as well as tests to evaluate tear fluid and the ocular surface were performed. RESULTS: After one drop of medication, tear secretion was significantly reduced by timolol, but not by latanoprost. At the end of the study the break-up time (BUT) was significantly decreased in the timolol group but not in the latanoprost group. The BUT still remained in the normal range in both groups, although it is important to note that timolol was administered at half the clinical dose. Both latanoprost and timolol tended to increase Rose-Bengal staining of the cornea and conjunctiva after one month of treatment but no statistically significant difference was found between the groups. Corneal sensitivity was within the normal range for all patients during the study. CONCLUSION: Regarding ocular surface effects, no clinically important differences between latanoprost and timolol were observed as all the effects remained in the normal range.

Adrenergic beta-Antagonists↗

Plasma timolol levels and systolic time intervals.

The beta-blocking potency of timolol was compared with that of propranolol under steady-state conditions in eight healthy subjects. The effects on systolic time intervals in healthy subjects and patients (n = 6) with coronary artery disease were evaluated in relation to varying timolol dose schedules and plasma concentrations. The beta-blocking potency was assessed by the inhibition of exercise-induced tachycardia. Timolol was eight times as potent as propranolol. There was wide between-patient variation (2.6 to 13.8) in timolol plasma concentration, and correlation between dose and peak (r = 0.61, p < 0.01) or nadir (r = 0.5 p < 0.01). There was a relatively weak correlation between timolol plasma concentration and degree of beta-blockade (r = 0.45, p < 0.05) and a linear correlation with dose (r = 0.98, p < 0.001). In healthy subjects timolol and propranolol had variable effects on systolic time intervals but in patients with coronary artery disease equipotent doses prolonged the preejection period, isovolumetric contraction time, and the ratio of the preejection period over the left ventricular ejection time. In patients as well as in normal subjects, the data indicated considerable beta-blocking effects for both drugs at the end of a 12-hourly dosing schedule, suggesting that twice-daily timolol and propranolol may be clinically practical.

Adult↗

Beta-adrenergic receptors in the elderly are not less sensitive to timolol.

The elderly have been reported to be less sensitive to the beta-adrenergic blocking effect of propranolol. However, propranolol is a racemate, and age-related changes in stereoselective metabolism or protein binding could confound interpretation of the data. To avoid these problems, we studied timolol in 12 young and 12 elderly healthy subjects. The dose of isoproterenol required for a heart rate increase of 25 bpm (I25) was determined before and 2 hours after an oral 10 mg dose of timolol. A dose ratio (DR) was calculated for each subject as the I25 after timolol/I25 before timolol. The binding constant for timolol binding to the receptor was calculated as the plasma timolol concentration divided by (DR-1). The I25 for the elderly group was significantly greater than the I25 for the young group, but the timolol binding constant was the same for both groups. We conclude that, although the elderly are less sensitive to isoproterenol, they are not less sensitive to timolol, and thus our data do not implicate a change in the interaction of beta-adrenoceptors with antagonists.

Adult↗

The comparative ocular hypotensive effect of apraclonidine with timolol maleate in exfoliation versus primary open-angle glaucoma patients.

PURPOSE: To compare the effect of adding apraclonidine 0.5% to timolol maleate 0.5% in patients with exfoliation versus primary open-angle glaucoma. Since exfoliation glaucoma is known to demonstrate higher pressures than primary open-angle glaucoma on timolol maleate therapy alone, the authors wished to determine whether apraclonidine equalised the intraocular pressure (IOP) between these two glaucomas when added to timolol maleate. METHODS: We age-matched 30 consecutive exfoliation and 30 primary open-angle glaucoma patients who had an IOP > or = 22 mmHg on timolol maleate alone. Patients underwent IOP diurnal curve testing on timolol maleate twice daily alone and, 2 months later, following the addition of apraclonidine 0.5% three times daily. Statistical analysis of the IOP at each time point was by an unpaired t-test between groups. A paired t-test was used to evaluate the reduction in IOP from baseline within groups after the addition of apraclonidine. RESULTS: On timolol maleate alone, exfoliation patients had a higher mean IOP at 06:00 and 10:00 hours as well as a higher peak, range and standard deviation of the IOP compared with primary open-angle glaucoma patients (p < 0.05). Following the addition of apraclonidine the mean, peak and range of IOP were statistically similar between groups and only the standard deviations remained higher in the exfoliation glaucoma group (p < 0.001). The mean diurnal IOP after apraclonidine was added was 20.5 +/- 7.0 mmHg in the exfoliation glaucoma group and 20.0 +/- 3.4 mmHg in the primary open-angle glaucoma group, which was not significantly different between groups (p = 0.73). CONCLUSIONS: This study suggests that apraclonidine 0.5% used adjunctively with timolol maleate 0.5% solution is associated generally with similar IOP control in exfoliation and primary open-angle glaucoma patients.

Adrenergic alpha-Agonists↗

Twenty-four hour control of intraocular pressure with dorzolamide and timolol maleate in exfoliation and primary open-angle glaucoma.

PURPOSE: To determine the efficacy and safety of adding dorzolamide 2% twice daily to timolol maleate solution 0.5% twice daily when treating exfoliation glaucoma or primary open-angle glaucoma. METHODS: This was a single-centre, crossover intra-individually controlled comparison. Sixty-two consecutive patients (31 with exfoliation glaucoma and 31 with primary open angle glaucoma) chronically treated with timolol maleate twice daily were included in this trial. Patients then had added dorzolamide 2% twice daily (08:00 and 20:00), instilled approximately 10 min after timolol maleate. Patients underwent diurnal intraocular pressure (IOP) testing (six measurements over 24 h), first on timolol maleate monotherapy and 2 months later following the addition of dorzolamide 2% as adjunctive therapy. RESULTS: On timolol monotherapy patients with exfoliation glaucoma had a higher mean IOP at 02:00, 06:00, 10:00, 14:00 and 22:00 hour time points as well as a higher maximum, minimum and range of IOP throughout the day compared with the primary open-angle glaucoma group (p < 0.05). Following the addition of dorzolamide as adjunctive therapy to timolol maleate there was a significant reduction in IOP (p < 0.05) at all time points in both glaucomas, but mean IOP at 10:00, 14:00, 18:00 and 22:00 hour time points, as well as the peak and range of IOP, remained higher in the exfoliation glaucoma group. No serious adverse events were noted with dorzolamide. Bitter taste, the most common symptom, was noted in 30% of patients. CONCLUSIONS: These data suggest that dorzolamide 2% used adjunctively with timolol maleate 0.5% solution is effective in reducing diurnal IOP in patients with primary open-angle and exfoliation glaucoma but does not alter the characteristics of higher IOP levels in the latter disease.

Adrenergic beta-Antagonists↗

A short term study of the additive effect of timolol and brimonidine on intraocular pressure.

PURPOSE: To evaluate the additive ocular hypotensive effect of the combination of brimonidine and timolol on intraocular pressure (IOP) reduction in patients with glaucoma. METHODS: This was a prospective, randomized, double-masked, crossover study in 20 patients with primary open angle glaucoma (POAG) on therapy receiving timolol maleate 0.5% twice daily, with IOP greater than or equal to 22 mmHg in one eye. The treatment period was 3 weeks and during this period timolol + brimonidine or timolol + placebo were applied topically twice daily and IOP, blood pressure, heart rate and pupil size were measured. RESULTS: Combined therapy (timolol + brimonidine) had clinically significant IOP-lowering effect during the treatment period P << 0.01). The mean diurnal IOP was significantly reduced by an average of 5.1-5.9 mmHg (21.2-24.5%) compared with baseline value. The timolol + placebo combination had no clinically significant IOP-lowering effect (P > 0.05). No clinically significant side effects were observed during the treatment of both groups. CONCLUSIONS: This study showed that the combination of topically applied brimonidine and timolol cause a marked and sustained IOP reduction.

Adrenergic alpha-Agonists↗

Diurnal intraocular pressure reduction with latanoprost 0.005% compared to timolol maleate 0.5% as monotherapy in subjects with exfoliation glaucoma.

AIMS: To compare the diurnal intraocular pressure (IOP) efficacy and safety of timolol vs latanoprost in subjects with exfoliation glaucoma (XFG). METHODS: A 3-month prospective, single-masked, active-controlled, parallel comparison performed in six centres in Greece that randomized subjects in a 1 : 1 ratio to either latanoprost in the evening (2000 hours) and placebo in the morning (0800 hours), or timolol twice daily (0800 and 2000 hours). RESULTS: In all, 103 subjects completed the study. After 3 months of chronic dosing, the latanoprost group exhibited a trend to a greater diurnal IOP reduction from an untreated baseline (24.9+/-3.2-17.4+/-2.9) compared with timolol (24.7+/-2.8-18.3+/-1.9 mmHg) (P=0.07). Latanoprost showed a significantly greater IOP reduction at 0800 hours (-8.5 vs -6.0 mm Hg for timolol, P<0.0001) whereas no difference was observed between the two medications at 1000, 1400, and 2000 hours after a Bonferroni Correction. In addition, latanoprost demonstrated a narrower range of diurnal IOP (2.4) than timolol (3.2 mmHg)(P=0.0017). Safety was similar between groups, except there was more conjunctival hyperaemia with latanoprost (n=8) than timolol (n=1)(P=0.01). CONCLUSIONS: This study suggests that latanoprost provides a statistically lower 08:00-hour IOP and better range of IOP than timolol in the treatment of XFG glaucoma.

Adult↗

(--)-Timolol is a more potent antagonist of the positive inotropic effects of (--)-adrenaline than of those of (--)-noradrenaline in human atrium.

1. The affinity of (--)-timolol for beta 1- and beta 2-adrenoceptors was determined on isolated atrial preparations from patients undergoing open heart surgery. The times for onset and offset of antagonism of the positive inotropic effects of (--)-adrenaline and (--)-noradrenaline by (--)-timolol were measured. 2. The antagonism of the positive inotropic effects of (--)-adrenaline and (--)-noradrenaline by (--)-timolol (0.1-100 nM) was simple competitive in human atrium tissue. The slope of Schild-plots was not significantly different from 1.0 [0.93 +/- 0.09 for (--)-adrenaline, 0.97 +/- 0.09 for (--)-noradrenaline]. 3. The inotropic effects of (--)-adrenaline were antagonized significantly more by each concentration of (--)-timolol than those of (--)-noradrenaline. KB-values (-log M) were 10.10 +/- 0.09 against (--)-adrenaline and 9.43 +/- 0.07 against (--)-noradrenaline (P < 0.001). 4. Blocking kinetics of (--)-timolol for the beta-adrenoceptor were relatively slow. Half-times for the onset of blockade by 10 times KB of (--)-timolol were approximately 30 min for both (--)-adrenaline and (--)-noradrenaline; offset times were similar. 5. It is concluded that (--)-timolol has a higher affinity for the beta 2-adrenoceptor than for the beta 1-adrenoceptor in human atrium. This property may be beneficial clinically in protecting against the beta 2-adrenoceptor hypersensitivity induced by cardiac beta 1-adrenoceptor blockade, but also explain why severe asthma can occur after administration of very low intra-ocular doses of the drug.

Adrenergic beta-Agonists↗