Timolol v guanethidine-epinephrine formulations in the treatment of glaucoma. An open clinical trial

P. F. Hoyng and N. L. Verbey

Patients with glaucoma received either 3% guanethidine-0.5% epinephrine (20 patients) or 1% guanethidine-0.2% epinephrine (20 patients) and then 0.5% timolol maleate. The fall in intraocular pressure during 3% guanethidine-0.5% epinephrine therapy (10.1 mm Hg [34.4%] reduction) was higher than during timolol therapy (7.5 mm Hg [25.5%] reduction) and the response to 1% guanethidine-0.2% epinephrine therapy (7.9 mm Hg [29%] reduction) equaled the response to timolol (7.3 mm Hg [26.8%] reduction). During 3% guanethidine-0.5% epinephrine therapy, 24 (67.7%) of 36 eyes had an average IOP lower than 22 mm Hg, compared with 16 (44.4%) of 36 timolol-treated eyes. With 1% guanethidine-0.2% epinephrine, IOP in 27 (73%) of 37 eyes was less than 22 mm Hg v 23 (62.2%) of 37 timolol-treated eyes. Both guanethidine-epinephrine formulations increased outflow facility. Since timolol produced few side effects, it appears to be the therapy of choice. However, in patients who do not respond sufficiently to timolol, both guanethidine-epinephrine formulations are potent alternatives.