Comparison of the cardiovascular effects of unoprostone 0.15%, timolol 0.5% and placebo in healthy adults during exercise using a treadmill test

Topical medical therapy and ocular perfusion pressure in open angle glaucoma: a systematic review and meta-analysis

Objective: We compared the benefits and harms of topical interventions for ocular perfusion pressure in open angle glaucoma. Methods: We searched the databases MEDLINE, EMBASE and CENTRAL for randomized controlled trials comparing topical hypotensive agents in glaucoma. Of the 9433 citations identified, 10 randomized controlled trials were included. We summarized data using random effects meta-analysis for post-treatment mean ocular perfusion pressure and using relative risk for adverse events. Results: Ten trials (416 patients) were included. The quality of included trials was low to moderate. There was a higher post-treatment ocular perfusion pressure with bimatoprost compared to timolol (1 trial, 32 patients, mean difference - 4.00 mmHg, 95% confidence interval -7.01 to -0.99, p = .009); heterogeneity was not significant (I² = 41%, χ² = 13.55, p = .09). Prostaglandins as a class had higher post-treatment mean ocular perfusion pressure compared to alternative interventions (5 trials, 147 patients, mean difference 2.19 mmHg, 95% confidence interval 0.67-3.70, p = .005); heterogeneity in the subgroup analysis was not significant (I² = 10%, χ² = 4.47, p = .35). Adverse events were found to be significant in only one of the studies comparing latanoprost to brimonidine, relative risk 3.67 (standard error 0.59, p = .03). Conclusions: We identified low to moderate quality evidence describing post-intervention mean ocular perfusion pressure in open angle glaucoma. Bimatoprost increases mean ocular perfusion pressure when compared to timolol. As a class, prostaglandins increase mean ocular perfusion pressure. Prostaglandins may provide beneficial ocular perfusion pressure profiles compared to alternative agents.

From Eye Drops to ICU, a Case Report of Three Side Effects of Ophthalmic Timolol Maleate in the Same Patient

Timolol Maleate (also called Timolol) is a nonselective beta-adrenergic blocker and a class II antiarrhythmic drug, which is used to treat intraocular hypertension. It has been reported to cause systemic side effects especially in elderly patients with other comorbidities. These side effects are due to systemic absorption of the drug and it is known that Timolol is measurable in the serum following ophthalmic use. Chances of life threatening side effects increase if these are coprescribed with other cardiodepressant drugs like calcium channel or systemic beta blockers. We report a case where an elderly patient was admitted with three side effects of Timolol and his condition required ICU admission with mechanical ventilation and temporary transvenous pacing. The case emphasizes the need of raising awareness among physicians of such medications about the potential side effects and drug interactions. A close liaison among patient's physicians is suggested.

Association between Ophthalmic Timolol and Hospitalisation for Bradycardia

Introduction. Ophthalmic timolol, a topical nonselective beta-blocker, has the potential to be absorbed systemically which may cause adverse cardiovascular effects. This study was conducted to determine whether initiation of ophthalmic timolol was associated with an increased risk of hospitalisation for bradycardia. Materials and Methods. A self-controlled case-series study was undertaken in patients who were hospitalised for bradycardia and were exposed to timolol. Person-time after timolol initiation was partitioned into risk periods: 1–30 days, 31–180 days, and >180 days. A 30-day risk period prior to initiating timolol was also included. All remaining time was considered unexposed. Results. There were 6,373 patients with at least one hospitalisation for bradycardia during the study period; 267 were exposed to timolol. Risk of bradycardia was significantly increased in the 31–180 days after timolol initiation (incidence rate ratio (IRR) = 1.93; 95% confidence interval (CI) 1.00–1.87). No increased risk was observed in the first 30 days or beyond 180 days of continuous exposure (IRR = 1.40; 95% CI 0.87–2.26 and IRR = 1.21; 95% CI 0.64–2.31, resp.). Conclusion. Bradycardia is a potential adverse event following timolol initiation. Practitioners should consider patient history before choosing a glaucoma regime and closely monitor patients after treatment initiation with topical nonselective beta-blocker eye drops.

An evidence-based review of unoprostone isopropyl ophthalmic solution 0.15% for glaucoma: place in therapy

Glaucoma is a progressive, neurodegenerative optic nerve disease that can cause significant visual morbidity and affects over 60 million people worldwide. The only known modifiable risk factor for glaucoma at this time is elevated intraocular pressure (IOP), which may be treated with medications, laser therapy, and/or incisional surgery. Topical ocular medications are commonly used as first-line therapy for glaucoma, although side effects may limit their use. Unoprostone is a novel 22-carbon ocular hypotensive agent that may be advantageous in treating some patients with open angle glaucoma or ocular hypertension. Unlike the 20-carbon prostanoids, such as latanoprost, that lower IOP primarily through an increase in uveoscleral outflow, unoprostone may lower IOP through increased aqueous outflow via the conventional trabecular meshwork pathway. Although not as efficacious as other prostanoids, unoprostone is effective for IOP reduction both as monotherapy and adjunctive therapy with timolol. Unoprostone has decreased affinity for the prostaglandin F2α receptor, which may explain its well tolerated ocular and systemic side effect profile compared with other prostanoids.

Ophthalmic timolol: plasma concentration and systemic cardiopulmonary effects

Timolol maleate is a non-selective beta-adrenoceptor antagonist currently used mainly as an ocular preparation for the treatment of glaucoma and ocular hypertension. Despite the topical administration, ophthalmic timolol causes systemic adrenergic beta-blocking because of absorption from the eye into the systemic circulation. Gel formulations of ophthalmic timolol have been developed to reduce systemic absorption and adverse effects in comparison with conventional aqueous solution formulations. Timolol is metabolized by the polymorphic cytochrome P450 2D6 enzyme (CYP2D6). The changes in heart rate (HR) are the most striking effects of the systematically absorbed fraction of ophthalmic timolol, with 0.5 % aqueous formulations presenting larger effects than 0.1 % hydrogel formulations, especially during exercise. Plasma levels of ophthalmic timolol correlate with the changes in HR. Neither 0.5 % aqueous nor 0.1 % hydrogel formulations of timolol have exerted noteworthy effects on systolic (SAP) or diastolic (DAP) arterial pressures, probably because of a compensatory increase in systemic vascular resistance due to the attenuation of HR. Ophthalmic timolol does not exert remarkable effects on pulmonary parameter peak expiratory flow (PEF) and forced expiratory volume in 1 s (FEV1) in non-asthmatic patients. CYP2D6 activity is clearly associated with the pharmacokinetic parameters, particularly when 0.5 % aqueous solution of timolol is used: peak plasma concentration, elimination half-life and area-under-the-curve are highest in CYP2D6 poor metabolizers. Finally, since there is a correlation between the plasma level of timolol and several haemodynamic effects - especially HR in the state of elevated beta-adrenergic tonus - the CYP2D6 poor metabolizers may be more prone to bradycardia during treatment with (aqueous) ophthalmic timolol.

The side effects of the prostaglandin analogues

In the last decade topically applied prostaglandin F2alpha analogues (bimatoprost, latanoprost, travoprost and unoprostone) have become widely used as a means to reduce elevated intraocular pressure in patients with glaucoma and ocular hypertension. These molecules all have similar side-effect profiles, which include both side effects that occur frequently (e.g., conjunctiva hyperaemia, increase of iris pigmentation and eyelash changes) and rare adverse reactions (e.g., periocular pigmentation, damage to the blood-aqueous barrier and cystoid macular oedema). Conjunctiva hyperaemia, eyelash changes and cystoid macular oedema are reversible, but certain other side effects, such as increased iris pigmentation, are not. However, the systemic side-effect profile is favourable for all the prostaglandin analogues, and some of the local side effects are only of cosmetic significance. Numerous clinical studies suggest that discontinuing treatment with prostaglandin analogues on account of their side effects is rare in clinical practice.

Polymorphisms of genes CYP2D6, ADRB1 and GNAS1 in pharmacokinetics and systemic effects of ophthalmic timolol. A pilot study

OBJECTIVE

To test the hypotheses that (1) CYP2D6 genotype is associated with pharmacokinetics of ophthalmic timolol and (2) variation in genotypes of ADRB1 (beta(1)-adrenoceptor) and GNAS1 (alpha-subunit of G-protein) modulate heart rate (HR), and systolic (SAP) and diastolic (DAP) arterial pressure responses to timolol.

METHODS

Nineteen glaucoma patients and eighteen healthy volunteers were treated with 0.5% aqueous and 0.1% hydrogel formulations of ophthalmic timolol using a randomised cross-over design. The participants conducted head-up tilt and maximum exercise test at four visits. Plasma concentration of timolol was measured twice for glaucoma patients and ten times for healthy volunteers on each visit. Also, the genotypes for CYP2D6, ADRB1 and GNAS1 were determined.

RESULTS

Among healthy volunteers using aqueous timolol, poor metabolisers (PMs, n=2) of CYP2D6 had higher maximum plasma concentrations (C(max), values 2.63 and 2.94 ng/ml), longer elimination half-lives ( T(1/2), 5.49 and 6.75 h), and higher area-under-curve (AUC, 19.54 and 23.25 ng.h/ml) than intermediate [IMs, n=6, mean+/-SD 1.73+/-0.59 ng/ml (not significant), 3.30+/-0.48 h, 11.32+/-3.72 ng.h/ml], extensive (EMs, n=8, 1.60+/-0.72 ng/ml, 3.24+/-1.24 h, 8.52+/-6.12 ng.h/ml) and ultra-rapid (UMs, n=2, values 1.23 and 1.67 ng/ml, 2.22 and 2.52 h, 6.16 and 6.94 ng.h/ml) metabolisers. The IMs, EMs and UMs did not differ from each other for any of the kinetic variables. Also, the elevation of HR from rest to maximum level tended to differ between PMs and IMs, and between PMs and UMs. The pharmacokinetics and pharmacodynamics between the CYP2D6 groups did not differ with statistical significance when hydrogel timolol was used. Upon head-up tilt, the Ser49 homozygotes (n=26) had higher SAP (P=0.03) and DAP (P<0.01) than the Gly carriers (n=11). The change in DAP from rest to maximum during exercise was lower (P<0.01) in subjects with CC alleles of GNAS1 (n=13) than those with at least one T allele (n=24).

CONCLUSION

The CYP2D6 poor metabolisers may be more prone to systemic adverse events with aqueous timolol than extensive metabolisers. Since CYP2D6 genotyping is not routine clinical practice, using 0.1% timolol hydrogel instead of 0.5% aqueous preparation will increase patient safety.

Effect of topical unoprostone isopropyl on optic nerve head circulation in controls and in normal-tension glaucoma patients

PURPOSE

To evaluate the effect of unoprostone isopropyl on microcirculation in the optic nerve head (ONH) of controls and patients with normal-tension glaucoma (NTG).

METHODS

Thirty healthy volunteers were randomly placed in a placebo group or a control group. For ten NTG patients, one eye was selected to receive the placebo drops and the contralateral eye received the unoprostone in a masked fashion. In both studies, the intraocular pressure (IOP) and the parameters of the blood hemodynamics of the ONH were obtained before and at 1 and 2 h after the instillation. Blood flow measurements were made with a scanning laser Doppler flowmeter.

RESULTS

In both control subjects and NTG patients, the changes in the IOPs after the instillation of either unoprostone or the placebo were not significant because almost all of the NTG patients had IOPs lower than 15 mmHg. Although the hemodynamic parameters were not significantly changed in the placebo-treated eyes of the controls, the eyes of the controls treated with unoprostone had mean blood velocity and flow values that were significantly higher than the baseline values 1 and 2 h after instillation (P < 0.01). The velocity values of the controls treated with unoprostone were significantly higher than in those controls receiving the placebo at 2 h postinstillation (P = 0.027). The values for the three circulation parameters (volume, velocity, flow) were significantly higher than the baseline values after instillation in the eyes of the NTG patients treated with unoprostone (P < 0.05). In contrast, none of these parameters was significantly different from the baseline in the eyes of NTG patients treated with placebo.

CONCLUSIONS

These results showed that unoprostone significantly increased microcirculation in the ONH in control subjects and in NTG patients without reducing the IOP significantly.

Association between low plasma levels of ophthalmic timolol and haemodynamics in glaucoma patients

OBJECTIVES

The aims of the study were to assess the correlation between the plasma concentration of ophthalmic timolol and cardiovascular parameters, and the influence of timolol on advanced haemodynamic variables, such as stroke (SI), cardiac (CI) and systemic vascular resistance (SVRI) indices and arterial pulse wave velocity (PWV).

METHODS

Twenty-five glaucoma or ocular hypertensive patients were treated with 0.5% aqueous and 0.1% hydrogel formulations of timolol using a randomised, double-masked, crossover, multicentre design. All the patients were subjected to passive head-up tilt, electrocardiography, exercise test and measurement of plasma concentration of timolol. In the analysis, the data on the two treatments were combined, and the Spearman correlation coefficients between the plasma level of timolol and physiological effects were calculated.

RESULTS

During the head-up tilt test before rising the bed up, the resting heart rate (HR; R=-0.52, P=0.001) and PWV (R=-0.34, P=0.04) were inversely correlated with timolol level. In the upright position, ophthalmic timolol effectively suppressed the rise in HR (R=-0.36, P=0.03). The SI did not change with timolol concentration, while CI diminished as timolol concentration rose (R=-0.39, P=0.02). The SVRI correlated with timolol concentration (R=0.38, P=0.02). In the exercise test, correlation between HR and plasma level of timolol steadily grew stronger as the load increased, reaching R=-0.60 (P<0.0001) at the maximum load. Systolic and diastolic arterial pressures were not associated with the timolol concentration.

CONCLUSION

The plasma concentration of ophthalmic timolol correlates with several haemodynamic effects. As HR decreases, SVRI increases and blood pressure is kept unchanged.

Safety of unoprostone isopropyl as mono- or adjunctive therapy in patients with primary open-angle glaucoma or ocular hypertension

This review summarises the safety of unoprostone isopropyl (both at the 0.12 and 0.15% concentrations) instilled twice daily in patients with primary open-angle glaucoma (POAG) or ocular hypertension (OH). For unoprostone 0.15%, combined data from two 12-month comparative monotherapy studies are reported, as well as data from three adjunctive therapy studies and two special population studies. With unoprostone monotherapy, most adverse events were mild or moderate and transient in nature. Less than 7% of unoprostone-treated patients discontinued therapy due to an adverse event. The most common adverse events associated with unoprostone were burning/stinging, burning/stinging directly upon drug instillation, ocular itching, and conjunctival hyperaemia. Unoprostone had no clinically notable effects on vital signs, laboratory profiles, or comprehensive ophthalmic examinations. One of 659 unoprostone 0.15%-treated patients had a change in iris colour after 12 months of monotherapy. Except for a higher incidence of burning/stinging and burning/stinging upon instillation, unoprostone was comparable to timolol 0.5% twice daily and betaxolol 0.5% twice daily. No safety concerns were raised with use of unoprostone as adjunctive therapy. Unoprostone had no significant effect on exercise-induced heart rate in healthy subjects or on pulmonary function in patients with mild-to-moderate asthma. The safety profile of unoprostone 0.15% was consistent with published information on the 0.12% formulation. In conclusion, unoprostone has an excellent safety profile in patients with POAG or OH.