Replacing maximum-tolerated medications with latanoprost versus adding latanoprost to maximum-tolerated medications: a two-center randomized prospective trial.

Purpose: To compare the replacement of every drug with latanoprost 0.005% once a day in glaucomatous eyes with poorly controlled intraocular pressure upon combination therapy, versus addition of latanoprost to the pre-existing treatment.

Study Design: prospective, investigator-masked, two-center, randomized clinical trial lasting 3 months.

Eligibility Criteria: open-angle glaucoma; IOP > or = 21 mm Hg upon the combination of a non-selective beta-blocker with pilocarpine or dorzolamide or both; no previous bulbar surgery; and prior glaucoma therapy lasting at least 2 years. Two treatment arms: (1) addition of latanoprost 0.005% QD to the pre-existing therapy [group A]; (2) substitution with latanoprost alone [group B].

Results: One hundred thirty-six eyes (68 eyes/treatment group) were randomized according to intraocular pressure level and the number of adjunctive medications to beta blocker. Both treatments provided a significant IOP decrease over baseline (from 23.5 +/- 1.4 to 19.7 +/- 1.9 mm Hg in group A, (P < 0.001); from 23.2 +/- 1.3 to 20.1 +/- 2.2 mm Hg in group B (P < 0.001), paired Student t test). At the end of the follow-up period, group A showed a higher number of intraocular readings less than or equal to 18 mm Hg than group B (42.6% vs. 30.8%; Fisher exact test: P = 0.018).

Conclusions: In eyes showing an intraocular pressure greater than 21 mm Hg upon combination therapy, the substitution of the pre-existing treatment with latanoprost can provide a significant IOP decrease. However, adding latanoprost to the pre-existing therapy is more likely to achieve a target intraocular pressure less than or equal to 18 mm Hg.