Evaluation of a 5% guanethidine and 0.5% adrenaline mixture (Ganda 5.05) and of a 3% guanethidine and 0.5% adrenaline mixture (Ganda 3.05) in the treatment of open-angle glaucoma

Double-masked cross-over comparison of Ganda 1.02 (guanethidine 1% and adrenaline 0.2% mixture) with gutt. adrenaline 1% (Simplene 1%) and with pilocarpine 1% (Sno-Pilo 1%)

A trial of the efficacy of low-concentration nonmiotic therapy was carried out, the aim being to minimise the side effects produced by 1% adrenaline or pilocarpine. A total of 77 eyes with open-angle glaucoma were studied in both parts of the trial. Thirty-nine eyes had a base-line pressure of over 28 mmHg and 28 eyes a pressure of 30 mmHg or over. In the comparison between Ganda 1.02 and adrenaline 1% (Simplene) the mean lowering of intraocular pressure was 8.6 mmHg with Ganda and 7.69 mmHg with Simplene. In the comparison between Ganda 1.02 and pilocarpine 1% (Sno-Pilo) the mean decrease was 6.34 mmHg with Ganda and 6.13 mmHg with Sno-Pilo. The resulting falls in intraocular pressure were highly significant statistically, but the differences between the effects of the 3 drugs were not significant. No significant side effects were reported with Ganda 1.02, and in particular no ptosis or superficial punctate staining of the cornea was noted.

A long term study of low concentration guanethidine and adrenaline therapy in glaucoma

A long term study was undertaken to evaluate the efficacy of combined guanethidine (1%) and adrenaline (0.05-0.5%) therapy in controlling intra-ocular pressure in 89 patients with chronic open angle glaucoma, in whom ocular tensions proved difficult to control on miotics and/or carbonic anhydrase inhibitors. Visual acuity, fields of vision, applanation tension, size of the pupil, anterior chamber depth and gonioscopic examination of the angle were recorded before and during treatment. The follow-up extended over a period of 12 to 42 months, the mean being 28 months. The combined therapy was found to lower the intra-ocular pressure significantly in a large number of patients and the most potent combination was guanethidine 1% and adrenaline 1/4% and the average fall of intraocular pressure with the combined therapy was around 8 mm Hg. Intolerance to the combined preparation was noticed in three patients during a period of 12-18 months with the symptoms of sore eyes, conjunctival hyperaemia and lid irritation of such severity that the treatment had to be withdrawn. Resistant to treatment developed in four patients during a period of 12-36 months and treatment had to be changed. Addition to guanethidine (1%) and adrenaline up to 1/4% to pilocarpine therapy (2-4%) in eyes with narrow angles did not result in any appreciable change of the width of the angle, the size of the pupil and the depth of the anterior chamber.

Control of glaucoma by reduced dosage guanethidine-adrenaline formulation

The effect of formulations of guanethidine and adrenaline of different composition has been tested in rabbits and in patients with glaucoma. The concentrations of guanethidine and adrenaline used for the rabbits were 5.0% and 1.0%; 2.5% and 0.5%; 1.0% and 0.2%; 0.5% and 0.1%. All except the lowest combination were equally effective in the magnitude of the decrease in intraocular pressure brought about and in their duration of activity. Two formulations containing guanethidine and adrenaline at concentrations of 3.0% and 0.5% and 1.0% and 0.2% respectively (formulated as Ganda drops by Smith and Nephew Pharmaceuticals Ltd) were tested in a blind, cross-over, short-term clinical trial on 20 patients. The drops containing the lower concentration of drugs were as effective as those of higher concentration. These results lead us to believe that most patients who respond to this treatment could be put on a reduced dosage regimen, which should result in a decreased incidence and severity of side effects.