advertisement
Abstract #15122 Published in IGR 8-4
Improved systemic safety and risk-benefit ratio of topical 0.1% timolol hydrogel compared with 0.5% timolol aqueous solution in the treatment of glaucoma
Uusitalo H; Kahonen M; Ropo A; Maenpaa J; Bjarnhall G; Hedenstrom H; Turjanmaa VGraefe's Archive for Clinical and Experimental Ophthalmology 2006; 244: 1491-1496
PURPOSE: The purpose of the study was to compare the systemic safety and risk-benefit ratio of 0.1% timolol hydrogel and 0.5% aqueous timolol eye drops in the treatment of glaucoma. METHODS: An 8-week randomised, double-blind, cross-over, multicentre study. A total of 25 patients with primary open-angle glaucoma, exfoliation glaucoma, or ocular hypertension was enrolled. After completing a wash-out period, patients were randomly chosen to receive either 0.1% timolol hydrogel once daily or 0.5% aqueous timolol eye drops twice daily. Intraocular pressure and heart rate during rest and exercise, head-up tilt test results, spirometry readings, and plasma concentrations of timolol were recorded. The risk-benefit ratio was determined by calculating the ratio between several heart rate endpoints and the change in intraocular pressure (IOP). RESULTS: The mean drug-induced change in the peak heart rate during exercise was -13.5 beats/min (SD 7.6) in the 0.5% aqueous timolol group and -5.1 beats/min (SD 6.7) in the 0.1% timolol hydrogel group (P < 0.001; 95% CI 4.06-12.18). There was no significant difference in the IOP-reducing efficacy between these compounds. The risk-benefit ratio was significantly improved when 0.1% timolol hydrogel was used, compared with 0.5% aqueous timolol in the exercise test. In the head-up tilt test the risk-benefit ratio was significantly improved at rest (P < 0.05), at 1 min (P < 0.05) and at 5 min (P < 0.001) after patients had received 0.1% timolol hydrogel. There were, however, no differences in spirometry readings. After patients had been treated with 0.1% timolol hydrogel, plasma concentrations of timolol were 1/6 (at peak) and 1/50 (at trough) of those of 0.5% aqueous timolol. CONCLUSIONS: Drug-induced changes in the peak heart rate, and head-up tilt test results as well as plasma concentrations of timolol, were significantly more pronounced after treatment with 0.5% aqueous timolol than with 0.1% timolol hydrogel. Because of the statistically similar IOP-reducing efficacy of these formulations the risk-benefit ratio was significantly improved when patients used 0.1% timolol hydrogel instead of 0.5% aqueous timolol.
Dr. H. Uusitalo, Department of Ophthalmology, University of Kuopio and Kuopio University Hospital, P.O. Box 1777, 70211, Kuopio, Finland, hannu.uusitalo@uku.fi
Classification:
11.16 Vehicles, delivery systems, pharmacokinetics, formulation (Part of: 11 Medical treatment)
11.3.4 Betablocker (Part of: 11 Medical treatment > 11.3 Adrenergic drugs)