The efficacy and safety of brimonidine 0.2% compared with timolol 0.5% in glaucoma: A randomized clinical trial on Taiwanese patients

Background. Brimonidine is a highly selective α-2 adrenergic receptor agonist with intraocular pressure (IOP) reducing effect. We conducted this study in Taiwan to compare the safety and efficacy of brimonidine 0.2% with timolol 0.5% for the treatment of glaucoma. Methods. A prospective, randomized, single-masked, 1-month clinical efficacy and safety trial was conducted from March to September 2000. Forty glaucoma patients were enrolled-- 29 in the brimonidine group and 11 in the timolol group. Patients instilled their study medications twice daily for 4 weeks, and were followed at baseline visit, weeks 2 and 4. Demographic data reduction of IOP, safety and adverse events were obtained and analyzed. Results. Both drugs showed sustained ocular hypotensive efficacy in the study period. At baseline, the mean IOP was 24.48±2.29 mmHg in the brimonidine group and 23.32 ± 0.82 mmHg in the timolol group. The IOP readings after treatment were significantly lower than their baseline levels in both groups at all visits (P < 0,001). At peak, the mean decreases from the baseline IOP ranged from 5.22 ± 0.30 mmHg to 6.96 ± 0.33 mmHg for brimonidine and from 4.55 ± 0.49 mmHg to 6.64 ± 0.53 mmHg for timolol. At trough, the mean decreases ftom baseline ranged from 3.72 ± 0.32 mmHg to 4.55 ± 0.32 mmHg for brimonidine and 3.82 ± 0.52 mmHg to 4.27 ± 0.51 mmHg for timolol. No significant between-group differences were seen at peak or trough at all visits. The clinical success rate was 86.2% in the brimonidine group and 81.8% in the timolol group, making no statistically significant difference between them (p = 0.817). 17.2% of patients in brimonidine group and 9.0% patients in timolol group reported mild adverse events. Ocular allergy occurred in 10.3% of patients in brimonidine group. No significant changes in visual acuity, biomicroscopy or ophthalmoscopy were observed in both groups. Mean systolic and diastolic blood pressure remained relatively stable in both groups except in week 2 (p = 0.016) when brimonidine had lower systolic blood pressure. However, brimonidine showed no significant difference in week 4 from baseline. The mean heart rate in the brimonidine group was relatively unchanged over the study period. Patients receiving timolol experienced statistically significant mean heart rate decreases from baseline (p = 0.020) in week 4. Conclusions. Topically applied twice daily for one month, brimonidine tartrate 0.2% has clinical effectiveness equivalent to timolol 0.5% in Taiwanese patients with glaucoma. It has a safe systemic profile with minimum effect on the heart.