[comparison of ocular hypotensive response to betaxolol and timolol and their topical and systemic side effects]

ABSTRACT

This is a study to compare the efficacy and side effects of betaxolol and timolol in lowering the IOP of primary open angle glaucoma or ocular hypertension. This Double-blind randomized cross-over clinical trial was conducted on 29 eyes of 20 patients with primary open angle glaucoma or ocular hypertension. Each patient received timolol 0.5% and betaxolol 0.5% [SINA DAROU] twice daily for four weeks in two phases. Before and between the two courses of treatment there was a wash-out period. At the end of the study the effect of these two drugs on intraocular pressure [lOP], mean arterial blood pressure, pulse rate, and basic tear secretion in addition to ocular symptoms were evaluated and statistically analyzed. The study was performed on 29 eyes of 20 patients with baseline IOP of 28,45 +/- 1.64 mmHg. After 4 weeks of treatment, timolol and betaxolol reduced IOP by 7.24 +/- 1.97 mmHg 25.36 +/- 1.22% and 3.55 +/- 1.18 mmHg 12.52 +/- 0.82%, respectively [P<0.001] and the difference between the two groups was also significant [P<0.001]. Mean arterial blood pressure was reduced with betaxolol and timolol by 6.37 +/- 3.96 mmHg [P<0.001], and 6.30 +/- 3.84 mmHg [P<0.001], respectively, but the difference between two groups was not statistically significant. Pulse rate was reduced with timolol and betaxolol by 7.37 +/- 3.22 beats /min, and 7.41 +/- 3.77 beats /min, respectively P>0.05. No significant difference was considered between two groups. Mean reduction in basic tear secretion with timolol and betaxolol was 1.31 +/- 0.66 mm/5min and 1.48 +/- 0.82 mm/5min, respectively; intergroup comparison was also not significant. Patients in 62.1% of the betaxolol group and 27.2% of the timolol group complained about eye burning. The differece between two groups was significant [P<0.01]. lacrimation-eye pruritis and bitter tastes was more in betaxolol group. Other symptoms were similar between two groups. Timolol is superior to betaxolol in treatment of early glaucoma or ocular hypertension, but both drugs should be used with caution in patients with cardiovascular compromise