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PubMed1983

Blind randomised non-crossover long-term trial comparing topical timolol 0.25% with timolol 0.5% in the treatment of simple chronic glaucoma.

The results of a 12-month blind randomised trial comparing the intraocular pressure lowering effect of timolol 0.25% with timolol 0.5% are presented. 27% of patients (22% of eyes) required additional antiglaucoma medication after a minimum time interval of 6 months to maintain an intraocular pressure less than 23 mmHg. The mean reduction in intraocular pressure (from pretreatment values) at 12 months was 24% for eyes treated with timolol 0.25% and 19% for eyes treated with timolol 0.5%. When reductions in intraocular pressure at each follow-up interval were statistically significant (timolol 0.25% treated eyes compared with timolol 0.5% treated eyes), the significance always favoured timolol 0.25%.

Administration, Topical↗
PubMed2000

Comparative study of timolol gel versus timolol solution for patients with glaucoma.

BACKGROUND: The timolol gel was developed for the simplification of multi-dose medications for glaucoma patients. This gel can be used once per day instead of twice per day of the aqueous form. It is necessary to understand the clinical effects of intraocular pressure maintained in glaucoma by there two forms of timolol. METHODS: Fifty-two eligible patients were included and completed the 12-week study. In this randomized, open-label, two-period crossover study design, patients received either the gel form of 0.5% timolol once daily or the aqueous form of 0.5% timolol twice daily for the first 6 weeks, then crossed over to the other treatment form for the remaining 6 weeks. Intraocular pressure was measured at baseline, week 6 and week 12 at the end of the treatment period. The incidences of all the adverse events were recorded and summarized in each follow-up visit. RESULTS: No statistically significant difference in intraocular pressure was observed between the two different control treatment groups (p>0.05). However, stickiness and transient blurred vision was reported more often by patients using the gel form than the aqueous form of timolol. CONCLUSIONS: The gel form of 0.5% timolol used once daily offers a new alternative that is probably more convenient than the aqueous form of 0.5% timolol given twice daily in maintaining the intraocular pressure of patients with glaucoma.

Adrenergic beta-Antagonists↗
PubMed1995

[Multicenter double-blind study with 0.25% timolol in Gelrite (TG) once daily vs. 0.25% timolol solution (TS) twice daily. German Study Group].

In a 12-week double-masked trial we compared the ocular hypotensive effect of 0.25% timolol in Gelrite administered once daily (TG) to that of 0.25% timolol solution administered twice daily (TS). A second objective was to compare the tolerability and the safety of these treatments. Timolol in Gelrite is a new topical formulation of timolol in an anionic heteropolysaccharide gellan gum. A total of 156 patients entered the study after an appropriate wash-out. The medication schedule included one drop of test drug in each eye at 9 a.m. (active drug for both groups) and 9 p.m. (placebo for the TG group, active drug for the TS group). At trough, the mean decrease from baseline intraocular pressure (after appropriate wash-out) ranged from 5.7 to 6.3 mmHg for the TG group and from 5.9 to 6.2 mmHg for the TS group. The difference between the treatment group means ranged from -0.4 to 0.4 mmHg. At peak, the mean decrease from baseline IOP ranged from 5.3 to 6.2 mmHg for TG group and from 5.1 to 6.1 mmHg for the TS group. The difference between the treatment group means ranged from -0.7 to 0.4 mmHg. The results of this study support the hypothesis of a comparable hypotensive effect at peak and trough of 0.25% timolol in Gelrite q.d. to 0.25% timolol solution b.i.d. Furthermore, timolol in Gelrite has an acceptable tolerability profile. The incidence of blurred vision was higher in the Gelrite group, but this different was not statistically significant. The incidence of foreign body sensation was significantly higher in the Gelrite group (P < 0.022).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1987

Effects of L-timolol, D-timolol, haloperidol and domperidone on rabbit retinal blood flow measured with laser Doppler method.

L-Timolol (0.4 mg/kg) reduced significantly retinal blood flow (17%), systemic blood pressure (18-20%) and heart rate (28%) in the rabbit. D-Timolol (4.0 mg/kg) increased retinal blood flow slightly (9%) and did not significantly affect systemic blood pressure or heart rate. Since D-timolol is effective in reducing intraocular pressure, these results indicate that D-timolol is superior to L-timolol for glaucoma treatment. Haloperidol and domperidone are dopamine antagonists, but, while haloperidol (0.1 mg/kg) suppressed retinal blood flow (16%), domperidone (0.2 mg/kg) increased it (12%). Neither of them affected blood pressure or heart rate significantly. While either of these given topically decreases intraocular pressure significantly, domperidone's ability to increase retinal blood flow makes it more useful than either haloperidol or L-timolol for treating glaucoma.

Animals↗
PubMed2003

Experience with Cosopt, the fixed combination of timolol and dorzolamide, after switch from free combination of timolol and dorzolamide, in Swiss ophthalmologists' offices.

PURPOSE: To analyse a response to the therapy switch from the concomitant application of beta-blocker and topical carbonic anhydrase inhibitor to the fixed combination of timolol and dorzolamide (Cosopt) in glaucoma/ocular hypertensive patients under everyday, office-practice conditions. PATIENTS AND METHODS: The data source was a survey among practising ophthalmologists in Switzerland assessing their experience with glaucoma patients/ocular hypertensives put for the first time on the fixed combination of timolol and dorzolamide. A total of 98 patients underwent the therapy switch in at least one eye. The intraocular pressure (IOP) change between the baseline visit before switch to the timolol-dorzolamide fixed combination occurred, and the first follow-up control after the switch, served as an indicator of compliance. RESULTS: The IOP decreased on average from 19.43 +/- 5.64 mmHg to 17.97 +/- 3.58 mmHg (p < 0.01). The time to the follow-up visit ranged from 4 to 354 days, and the magnitude of IOP change demonstrated a significant dependence on the time to the follow-up visit, also when corrected for baseline IOP level. A total of 87 (85.3%) continued on the timolol-dorzolamide fixed combination therapy after the first control visit. In 68 of these 98 patients the contralateral eyes underwent the same therapy switch, and their IOP followed an identical pattern of behaviour. CONCLUSION: The average IOP decrease of 1.5 mmHg upon therapy switch to the timolol-dorzolamide fixed combination suggests a better efficacy due to improved compliance. Short-term compliance benefit seems to be more pronounced. The high timolol-dorzolamide fixed combination therapy continuation rate reflects an improvement in compliance and subjectively-perceived convenience.

Adrenergic beta-Antagonists↗
PubMed2004

[Timolol 0.5%/dorzolamide 2% fixed combination versus timolol 0.5%/pilocarpine 2% fixed combination in primary open-angle glaucoma or ocular hypertensive patients].

PURPOSE: To establish the efficacy and safety of timolol 0.5%/dorzolamide 2% fixed combination versus timolol 0.5%/pilocarpine 2% fixed combination, each given twice daily, in primary open-angle glaucoma and ocular hypertensive patients. MATERIAL AND METHODS: In this prospective, multicenter, double-masked trial, 37 patients were treated twice daily with timolol for 4 weeks. Then, they were randomized to one of the treatment medications for 6 weeks, after which they were treated with timolol again for 2 weeks before placed on the opposite treatment medication for 6 weeks. RESULTS: A total of 36 patients completed the trial. The mean baseline intraocular pressure (IOP) was 22.3 +/- 3.7 mmHg. Following 6 weeks of treatment, the mean decrease of IOP was 18.0 +/- 2.2 mmHg for timolol/dorzolamide combination and 17.4 +/- 2.0 for timolol/pilocarpine combination. The mean diurnal curve IOP was 18.1 +/- 2.2 mmHg for timolol/dorzolamide group and 16.7 +/- 1.9 mmHg for timolol/pilocarpine group. These differences were statistically significant. Statistically more patients reported ocular pain and diminished vision during use of the timolol/pilocarpine combination. CONCLUSIONS: This study suggest that timolol 0.5%/pilocarpine 2% fixed combination can provide at least similar efficacious reduction in IOP as timolol 0.5 %/dorzolamide 2% fixed combination in patients with primary open-angle glaucoma and ocular hypertension.

Adrenergic beta-Antagonists↗
PubMed2006

Interlaboratory study of a NACE method for the determination of R-timolol content in S-timolol maleate: assessment of uncertainty.

Analyses of statistical variance were applied to evaluate the precision and practicality of a CD-based NACE assay for R-timolol after enantiomeric separation of R- and S-timolol. Data were collected in an interlaboratory study by 11 participating laboratories located in Europe and North America. General qualitative method performance was examined using suitability descriptors (i.e. resolution, selectivity, migration times and S/N), while precision was determined by quantification of variances in the determination of R-timolol at four different impurity levels in S-timolol maleate samples. The interlaboratory trials were designed in accordance with the ISO guideline 5725-2. This allowed estimating for each sample, the different variances, i.e. between-laboratory (s2(Laboratories)), between-day (s2(Days)) and between-replicate (s2(Replicates)). The variances of repeatability (s2r) and reproducibility (s2R) were then calculated. The estimated uncertainty, derived from the precision estimates, seems to be concentration-dependent above a given threshold. This example of R-timolol illustrates how a laboratory can evaluate uncertainty in general.

Adrenergic beta-Antagonists↗
PubMed1980

Capillary column GLC-mass spectrometric assay with selected-ion monitoring for timolol and [13C3]timolol in human plasma.

A method for the measurement of the beta-blocker timolol and its 13C3-labeled analog in human plasma is described. A known amount of an internal standard, [2H9]timolol, is added to each plasma sample. The method employs a reversed-phase C18 cartridge for isolation of the drug-containing fraction, capillary column GLC of the trimethylsilyl derivatives, and detection via selected-ion monitoring. The ions monitored for quantification (m/e 86 from timolol and m/e 89 and 95 from the 13C3- and 2H9-labeled analogs, respectively) arise from the side chains of the three compounds [e.g., CH2N+HC(CH3)3 for m/e 86]. Plasma levels of timolol and [13C3]timolol in human subjects given 5 or 10 mg of each compound were followed simultaneously for 12 hr postdosing. A detection level of 0.5 ng/ml of plasma was found. No evidence was found for a metabolic kinetic isotope effect since the ratios of the two species of drug in the plasma samples were the same as the ratios in the administered dose.

Gas Chromatography-Mass Spectrometry↗
PubMed2006

Robustness testing of a chiral NACE method for R-timolol determination in S-timolol maleate and uncertainty assessment from quantitative data.

A robustness test of a capillary electrophoresis method for the chiral separation of timolol in nonaqueous acidified media was performed. A two-level Plackett-Burman design was applied in which one qualitative and six quantitative factors were examined. Resolution, migration times and relative migration times to pyridoxine (selected as internal standard) were examined as qualitative responses to evaluate electrophoretic performance. A quantitative response, the content of R-timolol in S-timolol maleate sample, was also considered. Even though some significant factor effects were observed on the qualitative responses, it was still possible to quantify the R-timolol in the S-timolol maleate samples properly. The quantitative response was not significantly affected by the selected factors, demonstrating the robustness of the procedure. However, the use of different HDMS-beta-CD batches seemed to affect both types of responses necessitating to introduce a warning in the procedure. Since the experiments of the Plackett-Burman design can be assimilated to laboratories in an interlaboratory study, uncertainty can be evaluated using the robustness test data. The robustness test was set-up in such a way that the required variances could be estimated.

Adrenergic beta-Antagonists↗
PubMed2003

Timolol 0.5%/dorzolamide 2% fixed combination vs timolol maleate 0.5% and unoprostone 0.15% given twice daily to patients with primary open-angle glaucoma or ocular hypertension.

OBJECTIVE: To compare the efficacy and safety of timolol 0.5%/dorzolamide 2% fixed combination vs timolol maleate 0.5% and unoprostone 0.15% given twice daily. DESIGN: Prospective multicenter, randomized, double-masked, crossover comparison study. METHODS: Primary open-angle glaucoma or ocular hypertension patients were randomly assigned to one of the treatment groups for a 6-week treatment period and then crossed over to the opposite treatment. Diurnal curve testing was performed at 8:00 AM, 10:00 AM, 4:00 PM, 6:00 PM, and 8:00 PM at baseline and the end of each treatment period. The run-in medicine was timolol twice daily for 28 days. RESULTS: Thirty-two patients completed this trial. The baseline trough pressure was 24.3 +/- 3.0 mm Hg, and the diurnal curve was 23.4 +/- 3.2 mm Hg. For the fixed combination the treatment trough pressure was 20.8 +/- 4.1 mm Hg and the diurnal curve was 19.6 +/- 3.6 mm Hg, whereas timolol and unoprostone concomitant therapy showed a treatment trough pressure of 20.1 +/- 4.5 mm Hg and a diurnal pressure of 19.8 +/- 4.1 mm Hg. There was no significant difference between treatment groups at any time point, for the diurnal curve, or in the extended reduction from baseline. There was no difference between treatment groups regarding ocular and systemic unsolicited or solicited adverse events. Burning, stinging, and conjunctival hyperemia were the adverse events most noted. There were no serious adverse events during this trial. CONCLUSIONS: This study suggests that both timolol/dorzolamide 2% fixed combination and concomitant timolol maleate 0.5% and unoprostone 0.15% therapy provide similar efficacy and safety throughout the daytime diurnal curve.

Antihypertensive Agents↗
PubMed1990

Effects of D-timolol and L-timolol eye drops on intraocular pressure and aqueous flow. A dose-response study in normal eyes.

The effect on intraocular pressure of 0.5, 1.0, 2.0 or 4.0% D-timolol and 0.25 or 0.5% L-timolol was determined in healthy volunteers after a single topical application. A dose-response relationship for D-timolol could be established. The effect on a diurnal pressure curve and on aqueous humour production was about twice as large with 0.25% L-timolol as with 4.0% D-timolol.

Administration, Topical↗
PubMed1988

Low dose O-butyryl timolol improves the therapeutic index of timolol in the pigmented rabbit.

The degree of enhancement in the ocular absorption of timolol afforded by its O-butyryl prodrug and the possibility of reducing its systemic absorption through a proportional reduction in its instilled dose were investigated in the pigmented rabbit. A reversed phase HPLC procedure was used to assay for timolol and O-butyryl timolol in the aqueous humor and plasma over 120 min post-instillation of 25 microliter of drug solutions. We found that the ocular absorption of the O-butyryl prodrug of timolol from a 15 mM solution was 5.5 times greater than that of the parent drug while the systemic absorption was comparable. When a lower concentration of the prodrug (3.75 mM) was used the therapeutic index as assessed by the ratio of aqueous humor to plasma concentrations seemed to improve fifteenfold. Therefore, it is possible to significantly reduce the systemic absorption of timolol without reducing its ocular absorption by using a low dose of its O-butyryl prodrug.

Absorption↗
PubMed1989

Timolol-pilocarpine combined vs timolol and pilocarpine given separately.

In a controlled, double-observer, multicenter study, we compared the effect of a fixed combination of timolol 0.5%-pilocarpine 4% twice a day with that of timolol 0.5% twice a day plus pilocarpine 4% three times a day in 80 patients with open-angle glaucoma whose intraocular pressure was greater than 21 mm Hg on timolol 0.5% twice a day alone. Administered twice daily, the combination drug lowered intraocular pressure as effectively as concomitant treatment with timolol twice a day and pilocarpine three times a day. No statistically significant differences in reduction of intraocular pressure were found between the two groups nor were any unexpected side effects observed.

Blood Pressure↗
PubMed2003

Timolol 0.5%/dorzolamide 2% fixed combination versus timolol 0.5%/pilocarpine 2% fixed combination in primary open-angle glaucoma or ocular hypertensive patients.

PURPOSE: To establish the efficacy and safety of timolol maleate/dorzolamide fixed combination (TDFC) versus timolol maleate/pilocarpine fixed combination (TPFC), each given twice daily, in primary open-angle glaucoma or ocular hypertensive patients. METHODS: In this prospective, multicentred, double-masked trial, 37 patients were treated twice daily with timolol for 4 weeks. They were then randomized to one of the treatment medications for 6 weeks, after which they were treated with timolol again for 2 weeks before being placed on the opposite treatment medication for 6 weeks. RESULTS: A total of 36 patients completed the trial. Their mean baseline intraocular pressure (IOP) was 22.3 +/- 3.7 mmHg. Following 6 weeks of treatment, the mean trough (08.00 hours) IOP was 18.0 +/- 2.2 mmHg for TDFC and 17.4 +/- 2.0 mmHg for TPFC (p = 0.22). The mean diurnal curve IOP was 18.1 +/- 2.2 mmHg for TDFC and 16.7 +/- 1.9 mmHg for TPFC (p = 0.0007). At the remaining time-points (10.00, 18.00 and 20.00 hours), TPFC IOPs were statistically lower than TDFC IOPs (p < 0.03). There were statistically more unsolicited reports of vision change and ocular pain associated with TPFC (p = 0.04). Six patients were discontinued early from TPFC therapy (17%) versus two from TDFC (6%) (p = 0.13). CONCLUSIONS: This study suggests that TPFC can provide at least a similar efficacious reduction in IOP as TDFC in patients with primary open-angle glaucoma or ocular hypertension.

Antihypertensive Agents↗
PubMed2004

Comparing the fixed combination dorzolamide-timolol (Cosopt) to concomitant administration of 2% dorzolamide (Trusopt) and 0.5% timolol -- a randomized controlled trial and a replacement study.

PURPOSE: To compare the intraocular pressure (IOP) lowering effect of concomitant administration of 0.5% timolol and 2% dorzolamide and a fixed combination dorzolamide-timolol (Cosopt) To critically evaluate discrepancies between phase 3 clinical trials and prior replacement studies. DESIGN: A prospective, randomized, controlled clinical trial and a prospective, non-randomized comparative replacement trial. PARTICIPANTS/INTERVENTIONS: In a national multicentre trial, 131 patients were randomized to dorzolamide-timolol or a topical carbonic anhydrase inhibitor (CAI) and non-selective beta-blocker following a 1-month run-in using the separate components. Peak (maximal drug effect) and trough (minimal drug effect) IOPs were measured at baseline and 1 month after treatment. The replacement therapy study enrolled 404 consecutive glaucoma patients using a non-selective beta-blocker and dorzolamide and changed treatment to the fixed combination. Mean IOPs at the same time of day were compared before and 1 month after changeover. MAIN OUTCOME MEASURE: The main outcome measure was IOP, comparing baseline and on-therapy measurements at study conclusion between the two arms of the randomized trial and before and after switching therapy in the replacement trial. RESULTS: In the randomized trial, the mean baseline peak and trough IOPs were 18.4 and 21.0 mmHg in the group randomized to combination therapy and 17.6 and 19.8 mmHg in the dual drug group. After randomization and treatment for four weeks, the peak and trough IOPs were 17.6 and 19.5 mmHg in the combination group and 17.3 and 19.0 mmHg in the concomitant group. The percentage change in IOP was -3.2% at peak and -6.5% at trough for the combination and -0.3 and -3.2% for the concomitant group. These differences did not show statistical significance. In the replacement study, mean baseline IOP was 19.4 mmHg. Four weeks after initiation of treatment on the fixed combination, a significant additional IOP reduction of 1.7 mmHg (-8.8%) was observed (P < 0.0001). Overall, 81% of eyes exhibited equal or lower IOP on the fixed combination compared with concomitant therapy. CONCLUSION: The results of the randomized trial indicate that the fixed combination dorzolamide-timolol (Cosopt) was as effective as its components in controlling IOP, confirming results seen in phase 3 clinical trials. However, in the replacement study, utilization of the combination drug offered a statistically significant additional IOP reduction (P < 0.0001), which duplicates results from previous replacement studies.

Aged↗
PubMed1988

A study of the effects of four concentrations of D-timolol, 0.25% L-timolol, and placebo on intraocular pressure on patients with raised intraocular pressure.

The intraocular pressure lowering effect in 30 patients with raised intraocular pressure and open angles following a single application in a randomised double-masked fashion of four concentrations of D-timolol (0.25%, 0.5%, 1.0%, and 2.0%), 0.25% L-timolol, and placebo are presented. The percentage reduction in intraocular pressure after four hours following single-drop instillation range from 20% to 25% in the D-timolol group, 32% in the L-timolol group, and only 8% in the placebo group of treated eyes.

Adolescent↗
PubMed1989

Effect on the 24-hour diurnal curve of intraocular pressure of a fixed ratio combination of timolol 0.5% and pilocarpine 2% in patients with COAG not controlled on timolol 0.5%.

Eight patients with chronic open-angle glaucoma who had an intraocular pressure greater than 24 mm Hg at some time during the day while taking timolol 0.5% twice daily were given the fixed ratio combination of timolol 0.5% with pilocarpine 2% (TP2) twice daily. By comparing full 24-hour diurnal curves on timolol with those on TP2 it was possible to show that all patients except one (at a single timepoint) had an IOP less than 22 mm Hg when changed to TP2. The mean IOPs, the area under the diurnal pressure curve, and the diurnal variation were all significantly lower on TP2 twice daily than on timolol 0.5% twice daily.

Aged↗
PubMed1994

Determination of low plasma timolol concentrations following topical application of timolol eye drops in humans by high-performance liquid chromatography with electrochemical detection.

A simple and sensitive high-performance liquid chromatographic assay was developed for determination of timolol in human plasma following administration of two drops of a 5% timolol ophthalmic solution. A 4% butyl alcohol-hexane extract of an alkalized sample of plasma was chromatographed on a reversed-phase column and the components in the column effluent were monitored by coulometric detection. The extraction efficiency of timolol was 69.02 +/- 4.16% (mean +/- S.D.) and its detection limit was 107.2 pg/ml. The effect of mobile phase pH, buffer concentration and the working potential of the detector on column performance and the electrochemical response are described.

Chromatography, High Pressure Liquid↗