Comparison of the intraocular pressure lowering effect of latanoprost and a fixed combination of timolol-pilocarpine eye drops in patients insufficiently controlled with β adrenergic antagonists

Abstract

Aims - To compare the effect on intraocular pressure (IOP) of latanoprost monotherapy and timolol-pilocarpine in patients with glaucoma or ocular hypertension with inadequately controlled IOP on topical β adrenergic antagonists. Methods - This was a multicentre, randomised, observer masked, 6 week study performed in France and Sweden. 23 centres enrolled 237 patients with glaucoma or ocular hypertension and an IOP of at least 22 mmHg on treatment with topical β adrenergic antagonists, alone or in combination. After a 21 day run in period on timolol 0.5% twice daily, patients were randomised either to latanoprost 0.005% once daily or to a fixed combination of timolol-pilocarpine twice daily. Changes in mean diurnal IOP from the baseline to the 6 week visit were determined with an analysis of covariance. Results - Mean diurnal IOP was statistically significantly decreased from baseline in both groups (p < 0.001). Switching to latanoprost treatment reduced mean diurnal IOP by 5.4 (SEM 0.3) mmHg (ANCOVA -22%) and switching to timolol-pilocarpine treatment reduced mean diurnal IOP by 4.9 (0.4) mmHg (-20%). Blurred vision, decreased visual acuity, decreased twilight vision, and headache were statistically significantly more frequent in the timolol-pilocarpine group. Conclusions - Latanoprost monotherapy was at least as effective as fixed combination timolol-pilocarpine twice daily treatment in reducing mean diurnal IOP in patients not adequately controlled on topical β adrenergic antagonists. Latanoprost was better tolerated than timolol-pilocarpine regarding side effects. These results indicate that a switch to latanoprost monotherapy can be attempted before combination therapy is initiated.