A double-blind short-term trial of guanethidine 3% and adrenaline 0.5% combined in one eye drop

A double-blind short-term trial was done to test the effect of guanethidine 3% - adrenaline 0.5% (G-A) in a combined eye drop in 18 patients with open-angle glaucoma and one patient with narrow-angle glaucoma. In 9 of the 19 patients we expected an IOP lowering agent. There was one false-negative result. The mean fall in IOP due to G-A was 10.1 mm Hg (range 3 to 23) and 8.7 mm Hg (range-1 to 26) 6 and 8 h after application respectively. There was no effect on IOP in the 9 eyes that received the placebo.