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At least 577 records · Page 32Linked to original sources

PubMed1987

A double-masked study of timolol and pilocarpine combined.

In a double-masked, randomized, multicenter study, 25 patients received timolol 0.5%-pilocarpine 2% twice a day, 25 received timolol 0.5%-pilocarpine 4% twice a day, and 25 received pilocarpine 4% four times a day. The combination drugs showed an immediate, significant reduction in intraocular pressure of 7.2 mm Hg (25%) and 10.7 mm Hg (37%), respectively. The lowered intraocular pressure level was maintained throughout the three-week test period. With pilocarpine alone, intraocular pressure was reduced 5.3 mm Hg (19%). The mean intraocular pressure 12 hours after the last dose compared to two hours after the last dose was significantly higher both in patients receiving pilocarpine four times a day and in patients receiving timolol 0.5%-pilocarpine 4% twice a day (5.1 and 3.6 mm Hg, respectively), but not in patients receiving timolol 0.5%-pilocarpine 2% twice a day (2.6 mm Hg).

Clinical Trials as Topic↗

PubMed1983

Side effects of timolol.

Timolol maleate, a nonselective beta blocker, has been associated with adverse reactions when administered topically or systemically. The current literature pertaining to timolol-related side effects and reports to the National Registry of Drug Induced Ocular Side Effects are reviewed. Knowing what side effects are associated with the systemic administration of timolol is helpful in predicting systemic side effects that may be encountered when timolol is administered topically.

Administration, Topical↗

PubMed1992

Assay of timolol in human plasma using gas chromatography with electron-capture detection.

A simple and sensitive gas chromatographic method has been developed for the determination of timolol in plasma using electron-capture detection and propranolol as internal standard. Timolol was extracted using butyl chloride and derivatized using trifluoroacetic anhydride in butyl acetate. The lower detection limit for the assay was found to be 1 ng/ml from 1 ml of plasma. Extracted standards gave within-day precision of 12.55, 9.68 and 3.78% for 1, 20 and 100 ng/ml plasma samples, respectively. A recovery of at least 80% of timolol was found using the extraction method described. The assay was used in a randomized cross-over bioequivalence trial using an oral administration of 20 mg of timolol. Pharmacokinetic parameters compare favourably with other literature values.

Acetic Anhydrides↗

PubMedDate not supplied

Anticonvulsant and antiarrhythmic actions of the beta blocking agent timolol.

Cats were anesthetized with alpha-chloralose and pentylenetetrazol, 10 and/or 20 mg were administered intracerebroventricularly (i.c.v.) to elicit epileptiform activity, including both interictal and ictal discharges. Timolol, 10, 100, 500 micrograms/kg i.c.v. and 1, 5, 10 and/or 20 mg/kg i.v., was administered at 5 min intervals to determine whether it suppressed the epileptiform activity. Mean arterial blood pressure and heart rate increased after the administration of pentylenetetrazol; these increases were associated with the development of epileptiform activity and cardiac arrhythmias. All doses of timolol caused a decrease in the blood pressure and heart rate elevated by pentylenetetrazol and suppressed the epileptiform activity. Similar findings were obtained in cats that received the same doses of timolol administered at different time intervals. The data indicate that the central administration of timolol reverses the epileptiform activity of pentylenetetrazol in the brain and suppresses the associated increases in blood pressure, heart rate and cardiac arrhythmias.

Adrenergic beta-Antagonists↗

PubMed2006

Ketopinic acid and diisoproylideneketogulonic acid as chiral ion-pair selectors in capillary electrophoresis. Enantiomeric impurity analysis of S-timolol and 1R,2S-ephedrine.

1S,4R-(+)-ketopinic acid [(+)-KPA] has been introduced as a chiral selector for the separation of pharmacologically active amines by non-aqueous capillary electrophoresis (NACE). (+)-KPA gave enantioresolution for most of the compounds previously separated by 2R,3S,4R,5S-(-)-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid [(-)-DIKGA], but with a reversed migration order. A complete enantioresolution (Rs=4.2) was obtained for timolol, a compound that could not be resolved using (-)-DIKGA as the selector. Thus, (+)-KPA was evaluated for the enantiomeric purity determination of S-timolol. A method based on pre-concentration by transient isotachophoresis (tITP) provided a limit of detection (LOD) of 0.2% R-timolol in S-timolol samples. Because of the lack of enantioresolution of ephedrine when (+)-KPA was used as the selector, a method with (-)-DIKGA has been developed and validated for determination of the enantiomeric purity of the 1R,2S enantiomer. The method gave good precision and accuracy with an LOD (S/N=3) of 0.033% for the enantiomeric impurity 1S,2R-ephedrine.

Bridged Bicyclo Compounds, Heterocyclic↗

PubMed1995

Retrobulbar arterial hemodynamic effects of betaxolol and timolol in normal-tension glaucoma.

PURPOSE: beta-Adrenergic blocking drugs lower intraocular pressure. The question of whether these drugs also alter, either directly or indirectly, orbital hemodynamics is potentially of great importance for patients with normal-tension glaucoma who may have some degree of reversible vasospasm. METHODS: We compared the effect of selective (betaxolol) and nonselective (timolol) beta-adrenergic blocking drugs on flow velocities (as determined by color Doppler imaging) in orbital vessels in 13 patients with normal-tension glaucoma (mean age, 62 +/- 3 years; mean intraocular pressure, 15 +/- 2 mm Hg). A one-month drug treatment double-masked crossover design, with a three-week washout before each drug, was used. RESULTS: Neither drug changed peak systolic velocity in any of the four vessels studied (ophthalmic, nasal and temporal posterior ciliary, and central retinal arteries). Additionally, timolol did not alter end-diastolic velocity or resistance index (defined as [peak systolic velocity minus end-diastolic velocity] divided by peak systolic velocity) in any of the vessels measured. In contrast, betaxolol tended to increase end-diastolic velocity and to decrease resistance index: the four-vessel average end-diastolic velocity increased 30% (P = .08), and the four-vessel average resistance index decreased significantly (P = .04). These reductions in resistance index occurred despite that betaxolol, in contrast to timolol, did not significantly decrease intraocular pressure. CONCLUSIONS: These results suggest that, in patients with normal-tension glaucoma, selective beta-adrenergic blockade (betaxolol) may have ocular vasorelaxant effects independent of any influence on intraocular pressure, whereas nonselective blockade (timolol) lowers intraocular pressure without apparently altering orbital hemodynamics.

Arteries↗

PubMed1993

Effects of ocular carteolol and timolol on plasma high-density lipoprotein cholesterol level.

Fifty-eight healthy, normolipidemic adult men participated in a prospective, masked, randomized crossover study designed to compare the effects of two topical nonselective beta-adrenergic antagonists, carteolol and timolol, on plasma high-density lipoprotein cholesterol levels. Two eight-week treatment periods were separated by an eight-week drug-free period. Carteolol 1.0% or timolol 0.5% was used, one drop twice daily, in both eyes without nasolacrimal occlusion. Fresh plasma was assayed for levels of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and apolipoproteins A-I and B-100. With indistinguishable effects on intraocular pressure, carteolol and timolol induced different (P = .013) decrements in high-density lipoprotein cholesterol levels. Carteolol treatment decreased high-density lipoprotein cholesterol levels by 3.3% (-0.04 mmol/l) and raised the ratio of total to high-density lipoprotein cholesterol levels by 4.0% (0.15 unit); timolol treatment decreased high-density lipoprotein cholesterol levels by 8.0% (-0.10 mmol/l) and raised the ratio of total to high-density lipoprotein cholesterol levels by 10.0% (0.37 unit). There was no differential drug effect on the other lipid variables measured. Ocular nonselective beta-adrenergic antagonist therapy can produce clinically relevant decrements in high-density lipoprotein cholesterol levels in healthy men.

Administration, Topical↗

PubMed1983

Effects of topical timolol on corneal endothelial cell morphology in vivo.

To determine the effect of topical timolol on corneal endothelial cell morphology in a randomized, controlled, double-masked study of 40 healthy human eyes, we photographed the central corneal endothelium with a contact specular microscope before and after two weeks of treatment with placebo (20 eyes), with 0.5% timolol with 0.01% benzalkonium chloride (ten eyes), or with 0.5% timolol without benzalkonium chloride (ten eyes). From the specular photomicrographs, we analyzed five morphologic cell characteristics by means of electronic digitizer and microcomputer--cell density, mean cell area, the coefficient of variation for cell area, mean cell perimeter and a new feature quantifying cell shape. Statistical analysis of the data showed that two weeks of exposure to topical timolol or its preservative had no significant effect on corneal endothelial cell morphology in young, healthy eyes in vivo.

Adult↗

PubMed1991

Evaluation of once-daily levobunolol 0.25% and timolol 0.25% therapy for increased intraocular pressure.

In a three-month, double-masked, randomized clinical trial, we evaluated the once-daily ocular hypotensive efficacy of 0.25% levobunolol and 0.25% timolol in 80 patients with open-angle glaucoma or ocular hypertension. Thirty-seven of the 39 patients (95%) in the 0.25% levobunolol group and 35 of the 41 patients (85%) in the 0.25% timolol group successfully completed the three-month study period. The overall mean decrease in intraocular pressure was 5.3 mm Hg (22%) in the 0.25% levobunolol group and 5.4 mm Hg (22%) in the 0.25% timolol group. This difference was not statistically significant. In both treatment groups, effects on mean heart rate and blood pressure were minimal. The data suggest that levobunolol 0.25% and timolol 0.25%, administered once daily, are equally effective in the treatment of open-angle glaucoma and ocular hypertension.

Adult↗

PubMedDate not supplied

Effect of topical timolol on optic nerve head circulation in the cynomolgus monkey.

PURPOSE: To evaluate the effect of topical timolol on the optic nerve head (ONH) circulation in the cynomolgus monkey. METHODS: Eight cynomolgus monkeys were used. Timolol (0.5%, 30 microL) was instilled twice daily into 1 eye and physiological saline into the other eye for 7 consecutive days. The ONH tissue blood velocity (NB(ONH)) was determined using the laser speckle method. The determinations of NB(ONH) were carried out before the first instillation and 4 hours after the first, the seventh and the last instillation. The IOP was measured periodically. All measurements were performed in a masked manner. RESULTS: Twice daily 7-day instillation of 0.5% timolol showed no significant effect on the NB(ONH) in either eye, while the IOP was significantly decreased in both eyes. CONCLUSION: In the cynomolgus monkey, the ONH circulation was not affected by 7-day twice daily topical timolol treatment.

Administration, Topical↗

PubMedDate not supplied

Influence of topical betaxolol and timolol on visual field in Japanese open-angle glaucoma patients.

PURPOSE: To assess the effects of topical betaxolol and timolol on the visual field in Japanese open-angle glaucoma (OAG) patients. METHODS: This study was a multicenter, 2-year, prospective, randomized and double-masked study. Tests using the Humphrey 30-2 perimeter program were conducted every 6 months and the data of 95 patients were analyzed using regression analysis. Estimated regression coefficients for mean deviation (MD), corrected pattern standard deviation (CPSD), and total deviation (TD) values clustered into 15 sectors were obtained for each treatment group. RESULTS: Estimated slopes (dB/year) for MD and CPSD showed no significant difference from zero in either group. However, in the betaxolol group, estimated slopes (dB/year) for two adjacent sectors in the inferior arcuate area were significantly positive (P =.0135,.0116) while in the timolol group, no significant difference from zero was seen in any of the sectors. IOP changes from baseline in the timolol group were greater than in the betaxolol group, although no statistical significance was seen at any of the examination times. CONCLUSION: MD and CPSD showed no significant change in either group. In the betaxolol group, however, a significant trend in improvement of visual field performance was seen in the inferior arcuate subfield. Timolol reduced IOP more effectively than betaxolol in OAG patients.

Administration, Topical↗

PubMedDate not supplied

Clinical evaluation of a new formula of timolol maleate (WP-934 ophthalmic solution). WP-934 Study Group.

We investigated the ocular hypotensive effect and possible adverse reactions of a new timolol maleate formula, WP-934 ophthalmic solution, which is timolol maleate solution dissolved in a reversible thermo-setting gel. Once-daily instillation of 0.25 or 0.5% WP-934 ophthalmic solution was administered in a prospective, randomized manner at 29 institutions for 8 weeks to patients with primary open-angle glaucoma or ocular hypertension, and for another 16 weeks in a limited number of these patients. Patients were closely monitored throughout the study by ophthalmic and systemic examinations, and by continuous evaluation of symptoms. The new timolol formula demonstrated a significant ocular hypotensive effect throughout the study period. Adverse effects were minor. WP-934 ophthalmic solution, timolol maleate dissolved in a reversible thermo-setting gel, has a significant ocular hypotensive effect in eyes with primary open-angle glaucoma and ocular hypertension.

Administration, Topical↗

PubMed1988

High-performance liquid chromatography of timolol and potential degradates on dynamically modified silica.

A novel method for the determination of timolol in pharmaceutical products has been developed and is described. The method employs high-performance liquid chromatography (HPLC) on silica dynamically modified with the cetyltrimethylamomonium cation to quantitate the analyte. The use of this type of reversed-phase HPLC system for timolol determinations results in improved quality of chromatography, especially in terms of peak tailing and peak efficiency, in comparison to chromatography on bonded-phase silica. Column-to-column as well as manufacturer-to-manufacturer reproducibility for this separation on silica columns has been obtained and is better in our hands than that encountered with bonded-phase column packings. The method has been shown to be linear for the compounds studied, comparably accurate and precise to bonded-phase methods and specific for timolol in a variety of pharmaceutical formulations. Under the conditions specified, timolol can be successfully separated from its three potential degradates. Possible explanations of the primary retention mechanisms for the analytes are offered.

Administration, Cutaneous↗

PubMed1995

Avoiding unsuspected respiratory side-effects of topical timolol with cardioselective or sympathomimetic agents.

Topical timolol given for the treatment or chronic simple glaucoma may cause unrecognised bronchospasm among elderly people. We recruited 80 patients aged over 60 years, who were without a history of airways disease and already used timolol, into a randomised crossover study comparing the effects on spirometry and exercise tolerance of changing to betaxolol or dipivefrine therapy. Results showed an increase of 13% and 8% in mean peak flow rate and forced expiratory volume in 1 s (FEV1), respectively, when using betaxolol; and of 14% and 11% when using dipivefrine. There was also improved exercise tolerance with both agents. More than a quarter of the patients showed at least a 15% improvement in FEV1 when changed from timolol. Analysis of enrolment symptoms and response to nebulised salbutamol failed to produce a method of identifying these patients. Timolol may impair respiratory function and exercise tolerance of elderly patients even if they have no history of reversible airways disease.

Aged↗

PubMedDate not supplied

The efficacy of dorzolamide, a topical carbonic anhydrase inhibitor, in combination with timolol in the treatment of patients with open-angle glaucoma and ocular hypertension.

The effectiveness of dorzolamide 2%, a topical carbonic anhydrase inhibitor, administered three times daily (TID) concomitantly with timolol 0.5% given twice daily (BID) was evaluated in one arm of a large, 1-year, multicenter efficacy and safety trial. That study compared dorzolamide 2% TID with betaxolol 0.5% BID and timolol 0.5% BID as monotherapy in patients with open-angle glaucoma or ocular hypertension. Ninety-seven patients with uncontrolled intraocular pressure (IOP) (ie, greater than 21 mm Hg) or with a reduction in IOP of less than 15% from baseline during monotherapy with dorzolamide required 0.5% timolol BID as adjunctive therapy; 95 patients were evaluated for efficacy. IOP was measured 1 week after starting adjunctive therapy and at all subsequent study visits. Data were evaluated as change in IOP from original baseline and change in IOP from end of monotherapy treatment. A clinically meaningful additive effect on IOP was observed at all time points. After 1 week of adjunctive therapy, the mean percent reduction from baseline in peak and afternoon trough IOPs was 34% and 28%, respectively. These results demonstrate that dorzolamide and timolol have an additive effect in lowering IOP. This combination was generally well tolerated by the patients in this study.

Adrenergic beta-Antagonists↗

PubMed1979

Interaction of topical and oral timolol in glaucoma.

The interaction of oral and topical timolol maleate was studied in patients with open-angle glaucoma. The oral and topical preparations given separately produced a significant and comparable reduction of the intraocular pressure, but no additive effect was observed when both preparations were given together. Pulse- and blood pressure-lowering effects of oral timolol were not enhanced by the application of topical timolol. These systemic effects were not found in those patients using topical timolol alone.

Administration, Oral↗

PubMed1981

Prophylactic timolol for the prevention of high intraocular pressure after cataract extraction. A randomized, prospective, double-blind trial.

Eyes undergoing routine intracapsular cataract extraction (without alpha-chymotrypsin) often experience marked ocular hypertension in the first six hours after surgery. We conducted a randomized, prospective, double-blind study to determine if timolol maleate would prevent this increase in pressure. Thirty-five eyes undergoing routine cataract extraction were given a drop of either timolol 0.5% or placebo twice before and twice after surgery. Nine (56.3%) of 16 control eyes and 2 (10.5%) of 19 timolol-treated eyes had pressures above 30 mm Hg at six hours after surgery (P less than 0.025). Thus, prophylactic timolol 0.5% can substantially reduce the incidence of severe early postoperative ocular hypertension.

Cataract Extraction↗

PubMed1988

Intraocular pressure effects of timolol after unilateral instillation.

Beta-adrenergic antagonists are generally considered to lower intraocular pressure (IOP) of both eyes after unilateral instillation. In order to determine whether timolol also lowers IOP in the contralateral eye and to what extent, pressure curves were established in 14 normal, young subjects. Eye pressure curves on both eyes of each subject were measured before and 1 week after timolol 0.5% instillation twice daily in one eye. All subjects had an IOP decrease in the treated eye, but no subjects had a statistically significant IOP decrease in the contralateral eye. The mean IOP reduction was 26% in the treated eye, and only 3% in the contralateral eye. These results suggest that, in most cases, timolol does not lower IOP in the contralateral eye after unilateral instillation in normal subjects in contrast to certain glaucoma patients. These results suggest two different actions for timolol: (1) a local action in the treated eye, and (2) a systemic action where the pressure-lowering effect in the untreated eye is significant only in some pathologic conditions.

Adrenergic beta-Antagonists↗