Incidence of hyperemia associated with bimatoprost treatment in naïve subjects and in subjects previously treated with latanoprost.

PURPOSE: Bimatoprost is a potent hypotensive drug used in the treatment of glaucoma or ocular hypertension with lower target intraocular pressure (IOP) than latanoprost. Its most disturbing side effect is conjunctival hyperemia. The authors compared the extent of conjunctival hyperemia in patients receiving bimatoprost as initial therapy with that in patients whose treatment with latanoprost was replaced by bimatoprost.
METHODS: One group of consecutive patients with newly diagnosed bilateral primary open-angle glaucoma (POAG) was treated with once daily bimatoprost 0.03% ophthalmic solution as initial therapy. Treatment in another group of patients who had been on latanoprost treatment for at least 3 months was replaced by bimatoprost 0.03%. Conjunctival hyperemia was assessed by a single masked observer using a five-point grading scale.
RESULTS: The mean +/- SD baseline hyperemia scores were 0.4+/-0.3 and 0.70+/-0.3 for the firstline and replacement groups, respectively. Following 3 weeks of treatment, the mean posttreatment conjunctival hyperemia scores were 2.3+/-1 and 1.1+/-0.5, respectively. IOP of 25.2+/-9.8 mmHg and 18.95+/-2.1 mmHg dropped to 18.79+/-2.13 mmHg and 18.23+/-1.95 mmHg, respectively, following bimatoprost therapy. The differences in baseline levels of hyperemia for each group were not statistically significant (p=0.478). Changes in hyperemia scores from baseline were highly significant (p<0.001) only in first-line therapy patients (p=0.02 for the replacement group).
CONCLUSIONS: The above findings suggest that patients already on prostaglandin therapy may be less likely to experience an increase in conjunctival hyperemia induced by bimatoprost.