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Results for “Timolol”

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At least 775 records · Page 43Linked to original sources

PubMed1999

Primary open-angle glaucoma patients characterized by ocular vasospasm demonstrate a different ocular vascular response to timolol versus betaxolol.

We evaluated the retrobulbar response to a selective versus nonselective beta blocker in a subgroup of primary open-angle glaucoma patients (POAG) characterized by ocular vasospasm. Eleven patients who exhibited ocular vasospasm (i.e. a significant increase in ophthalmic artery blood flow velocity or a significant decrease in ophthalmic artery resistance index during hypercapnia) underwent medication washout for 4 weeks and were enrolled in a double-masked cross-over study (betaxolol versus timolol). Patients were evaluated for blood flow velocity of the retrobulbar vessels using color Doppler imaging, intraocular pressure, visual field sensitivity and contrast sensitivity at the beginning and end of each 4 week treatment period. Timolol treatment caused a significant reduction in IOP (p = .007), but no change in retrobulbar hemodynamics or visual function. After betaxolol treatment, resistance index fell significantly (p = .040) in the ophthalmic artery and increased significantly in both the central retinal (p = .003) and temporal posterior ciliary arteries (p = .030). Also following betaxolol treatment, contrast sensitivity improved significantly (p = .006), and a significant positive correlation was shown between change in contrast sensitivity and change in resistance index (r = .70; p = .015) of the ciliary arteries. POAG patients characterized by ocular vasospasm display a significant hemodynamic response to betaxolol, but not to timolol.

Adrenergic beta-Antagonists↗

PubMed2000

Xyloglucan as a novel vehicle for timolol: pharmacokinetics and pressure lowering activity in rabbits.

This study was aimed at verifying the performances of a mucoadhesive polysaccharide from tamarind seed (xyloglucan or TSP, tamarind seed polysaccharide) as an adjuvant for ophthalmic vehicles containing timolol. Three formulations (one experimental vehicle based on TSP and two reference commercial eye drops) containing 5 mg/ml timolol base equivalents were administered to the eyes of pigmented rabbits. Drug concentrations in tear fluid, cornea, iris-ciliary body, aqueous humor and plasma were determined, as well as intraocular pressure. The polymer under investigation, in spite of a comparatively low viscosity, produced high timolol concentrations in the ocular tissues and a low systemic absorption. The performances of the TSP vehicle were comparable to those of a reference "in situ" gelling formulation (Timoptic XE). The results point to TSP as a potentially useful adjuvant for ophthalmic delivery systems.

Adrenergic beta-Antagonists↗

PubMed2006

Ocular powder: dry topical formulations of timolol are well tolerated in rabbits.

PURPOSE: Although eye drops are the most common form of ocular drugs, they have several limitations. Drug absorption into the eye is, in general, less than 5%, addition of preservatives is often necessary, and many drugs cannot be formulated as eye drops. Formulating ocular drugs as powder may solve these problems. The aim of this study was to investigate ocular irritation in rabbits following powder administration. METHODS: Timolol maleate (TM) powder was administered to pigmented lop rabbits. Both pure TM powder and freeze-dried with PVP-polymer (2.4% of mass) were tested in 1.0- and 0.1-mg doses. Additionally, 4 rabbits received 0.1 mg of the pure powder 3 times a day for 8 d. Redness of the bulbar conjunctiva and the amount of discharge was rated from photographs (0-3 points, randomized and masked evaluation). The 8-d experiment additionally included examination with a slit lamp and examination of hematoxylin-eosin stained sections of eyes with light microscopy. RESULTS: No serious or irreversible signs of irritation were noted. Doses of 1.0 mg were more irritating than 0.1-mg doses. There was no detectable difference in irritation between pure or freeze-dried powder. Slit-lamp examination, surface photographs and histology showed a negligible difference between drug and control eyes following the 8-d experiment. CONCLUSIONS: The results suggest that 0.1 mg of timolol powder does not irritate the eye and that testing topical timolol powder in humans is feasible.

Animals↗

PubMed2000

Comparison of the effects of 0.5% timolol maleate, 2% carteolol hydrochloride, and 0.3% metipranolol on intraocular pressure and perimetry findings and evaluation of their ocular and systemic effects.

PURPOSE: To compare the effects of 0.5% timolol maleate, 2% carteolol, and 0.3% metipranolol on intraocular pressure (IOP) in 45 patients with primary open-angle glaucoma (POAG) and ocular hypertension. A secondary goal of this study was to evaluate the ocular and systemic side effects of these medications. METHODS: Measurements of IOP were taken at baseline (pretreatment) and 2, 6, and 12 hours after instillation on treatment days 15, 30, 60, and 90. Mean sensitivity (MS) and mean defect (MD) values of perimetry before and after treatment and the effects of the three beta blockers on serum lipid profiles were determined. Ocular and systemic side effects were recorded. RESULTS: The most prominent IOP lowering effect was noted with metipranolol at 2 and 6 hours on day 15, and with timolol maleate at 12 hours on day 15 and at all hours of the subsequent days on which measurements were taken. Timolol maleate produced a significant decrease in IOP at 12 hours on day 15 compared with carteolol. There was not a statistically significant difference between the MS and MD values on perimetry before and after treatment for any treatment. There was a statistically significant decrease in levels of total cholesterol and high-density lipoprotein (HDL) cholesterol and a significant increase in triglyceride levels; these changes were observed for all treatments. CONCLUSION: The effects of the three medications were not statistically different from each other in terms of IOP reduction and visual field changes. Careful monitoring of blood lipid levels is necessary with long-term treatment with beta blockers, because these agents reduced serum levels of HDL and total cholesterol while increasing triglycerides. Such changes in lipid levels could lead to increased incidence of complications, particularly in patients with atherosclerosis or coronary heart disease.

Adrenergic beta-Antagonists↗

PubMed2000

Additive effect of latanoprost to the combination of timolol and dorzolamide.

PURPOSE: To study the additive effect of latanoprost 0.005% in patients who have uncontrolled intraocular pressure (IOP) using timolol 0.5% and dorzolamide 2%. METHODS: Fifty-two consecutive patients with open-angle glaucoma who were using timolol and dorzolamide and were considered to have IOP above their defined target pressure were included in this study. After a baseline diurnal tension curve (DTC) was performed, latanoprost once a day was added to the treatment, and a second DTC was performed 1 week later. RESULTS: Five patients (9.6%) were discontinued from treatment because of side effects. The remaining 47 patients showed a significant IOP reduction of 3.1 mm Hg (16%) from a baseline of 19.3 mm Hg (mean IOP registered during DTC; P < or = 0.0001). Seventeen patients (36.3%) showed a mean IOP reduction greater than 20%. CONCLUSIONS: Latanoprost had an additive effect when used as a third drug for patients on timolol and dorzolamide who were in need of further IOP reduction. These results suggest that latanoprost may be very effective in some patients with poorly controlled glaucoma on multiple therapy.

Adrenergic beta-Antagonists↗

PubMed1983

Haemodynamic and metabolic effects of timolol (Blocadren) on ischaemic myocardium.

The effects of timolol (2.5 mg i.v.) on coronary haemodynamics and myocardial metabolism were studied in 26 patients with angina pectoris. Cardiac venous flow (CVF) was measured by thermodilution technique. Blood was sampled for metabolic studies. Angina pectoris was induced by atrial pacing and the same heart rate was regained after timolol. Metabolic ischaemia was defined as reduction in myocardial lactate extraction ratio (MLE) by at least 50% and to a ratio below 0.15. The study was completed in 22 patients, 9 of whom fulfilled the metabolic criteria for ischaemia. This subgroup did not differ from the total group in any other respect than in lactate metabolism. Beta-adrenergic blockade reduced myocardial oxygen consumption (MVO2) and CVF significantly at rest, but MVO2, CVF, myocardial glucose uptake and MLE were unchanged during pacing despite a decrease in systolic aortic pressure, ejection time and reduced myocardial free fatty acid uptake. Conclusively, timolol did not reduce MVO2 and metabolic ischaemia during pacing-induced angina.

Angina Pectoris↗

PubMed1984

Effects of timolol on platelets in coronary sinus blood and on myocardial ischemia during pacing-induced angina.

The effect of timolol on blood platelet function was studied in coronary sinus and caval vein blood at rest and during pacing-induced angina in 20 patients with coronary heart disease. During pacing-induced angina, lactate measurements confirmed that coronary sinus blood was sampled from ischemic regions in 13 men. The ischemia did not influence platelet function. In blood from non-ischemic myocardium, platelet activation was found during pacing: the ADP-induced aggregation, platelet retention and plasma beta-thromboglobulin levels increased moderately but significantly. Timolol administration prevented this platelet activation, possibly by inhibiting catecholamine release from the myocardium, and reduced the ischemic response during pacing as judged from lactate measurements and ST depressions. It is concluded that timolol reduced platelet activation induced in non-ischemic regions of the heart during tachycardia stress as well as myocardial ischemia.

Adult↗

PubMed1988

The effect of enalapril and timolol on blood lipids. A randomized multicenter hypertension study in general practice in Norway.

In a 24-week randomized, single-blind study Timolol (n = 63) and Enalapril (n = 57) proved to be potent and safe antihypertensive drugs. However, the effect on lipid metabolism was fundamentally different, despite the fact that the effect on total serum cholesterol did not significantly differ between the two groups. Enalapril had no adverse effect on any lipid fractions, while Timolol increased very low (VLDL) + low (LDL) density lipoprotein cholesterol by 7.6% (p less than 0.001) and total triglycerides by 34.5% (p less than 0.001), and decreased the favorable high density lipoprotein (HDL) cholesterol by 11.3% (p less than 0.001). Thus, the ratio HDL/VLDL + LDL cholesterol was reduced by 17.1% (p less than 0.001). Enalapril reduced uric acid by 3.4% (NS), while Timolol increased uric acid by 4.0% (p less than 0.05). The difference between the groups was statistically significant (p less than 0.01). The first steps in any attempt to solve the hypertension-coronary dilemma should be to take into consideration all pharmacologic effects of antihypertensive drugs.

Adult↗

PubMed1982

Relationships among timolol doses, plasma concentrations and beta-adrenoceptor blocking activity.

1 We investigated the relationships among dose, plasma concentration and beta-adrenoceptor blockade after single and repeated doses (0.5-20 mg) of timolol and placebo in six normal men. 2 Maximal suppression of exercise-induced tachycardia (bicycle ergometry) was dose-dependent and greater at 2 than at 6 h after dosing; activity up to 12 h was evident on the last dosing day. 3 Attenuation of exercise-induced tachycardia was strongly correlated with the timolol dosage over the 0.5 to 5-10 mg range. 4 A plasma timolol concentration of 27 ng/ml was associated with maximal suppression of exercise-induced tachycardia. 5 Suppression of exercise-induced tachycardia and areas under the plasma concentration-time curves did not differ significantly on the first and last dosing days.

Adrenergic beta-Antagonists↗

PubMed1989

A comparison of the ocular hypotensive effect of 0.025% bromocriptine and 0.25% timolol eye drops in normal human volunteers.

1. The ocular hypotensive effect of 0.025% bromocriptine and 0.25% timolol eye drops was compared in nine healthy human volunteers, using non-contact tonometry. 2. Considering all post-dosing measurements compared with placebo and including the baseline values as continuous independent variables, using multiple linear regression analysis, both bromocriptine and timolol had a significant ocular hypotensive effect (P less than 0.0001) in the treated eye with a significant but lesser effect in the contralateral eye. 3. In the concentrations used, timolol was more efficacious than bromocriptine in lowering intraocular pressure (P less than 0.025). 4. Using other forms of vehicles for bromocriptine to improve efficacy and studying the ocular hypotensive effect of topical application of other dopamine-2-receptor agonists such as pergolide and lisuride was suggested.

Adult↗

PubMed1989

Timolol metabolism and debrisoquine oxidation polymorphism: a population study.

1. The metabolism of orally administered timolol (T) to its ring cleavage ethanolamine (TE) and glycine (TG) products was studied in 108 unrelated hypertensive patients. 2. Statistically significant correlations between the 0-8 h urinary debrisoquine/4-hydroxy-debrisoquine ratio and the T/TE (rs = 0.74, P less than 0.001), T/TG (rs = 0.42, P less than 0.001) and T/TE + TG (rs = 0.49, P less than 0.001) ratios were found. 3. The log10 T/TE, T/TG and T/TE + TG ratios from poor metabolisers of debrisoquine (PMs) were grouped at the upper end of a unimodal distribution. 4. These results indicate that timolol metabolism is partly under monogenic control of the debrisoquine-type. 5. The mean +/- s.d. plasma timolol concentration in PMs (82 +/- 43 ng ml-1) was double that in extensive metabolisers (45 +/- 19 ng ml-1) (P = 0.011). The clinical significance of this observation remains to be established.

Adult↗

PubMed2006

Effect of 2% dorzolamide on retinal blood flow: a study on juvenile primary open-angle glaucoma patients already receiving 0.5% timolol.

AIM: To investigate whether dorzolamide modifies peripapillary retinal haemodynamics in juvenile primary open-angle glaucoma (JPOAG) patients treated with timolol. METHODS: In 40 JPOAG subjects, before and after dorzolamide coadministration with timolol, the following examinations were achieved: intraocular pressure (IOP), blood pressure (BP), ocular perfusion pressure (OPP), heart rate (HR), visual field and retinal flowmetry. RESULTS: Adjunctive therapy with dorzolamide induced the following modifications: IOP reduction [1.75 mmHg, 95% confidence interval (CI) 1.23, 2.26; P < 0.05], OPP increase (5.09 mmHg, 95% CI 2.97, 7.20; P < 0.02) and retinal blood flow improvement (35.0 arbitrary units, 95% CI 12.20, 57.80; P < 0.03). BP, HR and visual field indices did not change. CONCLUSIONS: Dorzolamide, in association or in fixed combination with timolol, significantly improves retinal blood flow in JPOAG patients.

Adolescent↗

PubMed1980

Transfer to timolol: selective use of a new mode of therapy.

Many patients on long-term anti-glaucoma therapy were found to need better treatment because of lack of control and/or troublesome symptoms or signs. One hundred and ninety such patients with a wide range of glaucomas were observed during transfer to treatment with timolol maleate. This drug alone or in some combination, controlled two out of three patients. Some cases benefited from distinctive effects not easily provided by any other drug. Some patients were unresponsive and as time progressed an increasing number of early responders showed tachyphylaxis. As the result of experience in this series, timolol is not yet recommended for initial or cavalier use in all glaucomas or all patients. Because the drug is so new, special indications should be recognised by which timolol can be used selectively and with continuing caution for a further period.

Adult↗

PubMed1996

A 6-month, randomized, double-masked comparison of latanoprost with timolol in patients with open angle glaucoma or ocular hypertension.

The intraocular pressure reducing effect and side-effects of latanoprost, a phenyl-substituted prostaglandin analogue, were compared with those of timolol, in a group of 31 glaucomatous or ocular hypertensive patients, divided into three subgroups. The study was randomized and double masked. At the end of 6 month's treatment with latanoprost 0.005% once daily, either as a morning dose or as an evening dose, there was a reduction in intraocular pressure of 33% (p < 0.001) and 36% (p < 0.001), respectively. The intraocular pressure reduction of timolol 0.5%, administered twice daily was 26% (p < 0.001). There was no significant difference in conjunctival hyperemia between the groups and there were few subjective symptoms in any of the patients. One patient with a light green-brown iris, treated with latanoprost in one eye only, exhibited an increase in iris colour in the treated eye at week 26, and did not show any signs of reversion 9 months after discontinuing the therapy. It may be concluded that latanoprost is well tolerated and at least as effective as timolol in reducing intraocular pressure in patients with glaucoma or ocular hypertension when applied once daily. The exact mechanism behind the increase in iris pigmentation and the clinical significance of this previously unknown side-effect needs to be investigated further.

Adrenergic beta-Antagonists↗

PubMed1988

Effects of a beta-blocking agent, timolol maleate, on saliva in healthy volunteers.

The effects of timolol maleate on the secretion and composition of human saliva were studied in vivo. Eight healthy volunteers received orally 10 mg timolol maleate. Stimulated parotid saliva samples, resting whole saliva samples, and blood samples were collected immediately before and four times after the drug intake at intervals of 1 h. The levels of total protein, lysozyme, IgA, IgG and IgM, salivary peroxidase, myeloperoxidase, lactoferrin, amylase, thiocyanate (SCN-), and hypothiocyanite (OSCN-) were analyzed from saliva samples. Drug levels were measured both from parotid saliva and blood samples. Results were compared to the analyses of the samples collected in a similar way but without administration of any drugs. Decreased levels of total protein, lactoferrin, amylase, and salivary peroxidase were observed in parotid saliva after a single oral dose of timolol maleate. No such decrease was found in lysozyme, myeloperoxidase, SCN-, OSCN-, or immunoglobulins. Salivary flow rate was not significantly changed after drug intake. The results suggest that the beta-blocking drug may cause qualitative changes in the composition of saliva by inhibiting the synthesis and/or release of acinar proteins.

Amylases↗

PubMed1980

Timolol versus pilocarpine separately or combined with acetazolamide-effects on intraocular pressure.

Fifty-eight patients with intraocular hypertension or primary open angle glaucoma participated in a double masked randomized study. Timolol in concentrations 0.25% and 0.5% was compared with 1, 2, or 4% pilocarpine Acetazolamide (250 mg x 3) was added if intraocular pressure (IOP) was uncontrolled with the highest concentrations tested. No statistical difference was found in hypotensive effect between pilocarpine and timolol neither on ocular hypertensions nor glaucomas. The additive hypotensive effect of acetazolamide was the same for both substances. Once a day by administration of timolol was sufficient in 17 of 20 cases controlled merely by topical administration.

Acetazolamide↗

PubMed1982

Preoperative timolol and ocular compression in cataract surgery.

The intraocular pressure (IOP) reducing effect of topical timolol with digital ocular compression for the prevention of vitreous loss in cataract surgery was compared with the effect of combined acetazolamide-mannitol pre-medication with digital compression. In the timolol group of 30 patients the mean IOP reduced from 11.4 mmHg before the compression to 8.2 mmHg after it. In the acetazolamide-mannitol group of 29 patients the mean IOPs were 10.9 and 5.6 mmHg, respectively. The reduction of IOP was statistically highly significant in both groups. There was no case of vitreous loss and the post-operative healing was uncomplicated in both groups of patients. The application of timolol was easy and time saving, but acetazolamide-mannitol pre-medication created deeper hypotony after ocular compression, which was probably due to the vitreous reducing effect of mannitol.

Acetazolamide↗

PubMed1982

The ocular hypotensive effect of timolol in long-term treatment of glaucoma. A 4 year study.

The ocular hypotensive action of timolol used alone and in combination with other antiglaucoma drugs was studied in 33 patients with glaucoma, 19 glaucoma suspects and 12 patients with ocular hypertension in a treatment period of 4 years. During the 2nd-4th year the mean IOP increased 8-10% (P less than 0.05) in both glaucoma patients and patients with ocular hypertension or suspected glaucoma. The success rate on timolol alone (a persistent IOP less than 20 mmHg) was 43.6% in patients with manifest glaucoma. In 18% of the patients an aggravation of pre-existing visual field lesion or new visual lesions developed. Nine patients (14%) - 3 on timolol alone and 6 on additional treatment regime - had to be operated due to definite insufficiency of pressure reduction.

Drug Therapy, Combination↗