Additive effect of latanoprost and dorzolamide in patients with elevated intraocular pressure

Purpose: To evaluate the additive ocular hypotensive effect of latanoprost and dorzolamide in combination, on intraocular pressure reduction in patien ts with elevated intraocular pressure (IOP). Methods: Thirty patients with ocular hypertension or early capsular or primary open-angle glaucoma and el evated IOP were randomly assigned to two parallel treatment groups. The tre atment period was twenty days. Fifteen patients (Group 1) received latanopr ost once daily during the first ten days and, in addition, dorzolamide thre e times daily during the second ten days. Fifteen patients (Group 2) receiv ed dorzolamide three times daily during the first ten days and, in addition latanoprost, once daily during the second ten days. IOP was measured and c onjunctival hyperemia was evaluated. Results: In Group 1, the mean IOP on d ay 0 was 26.8 mmHg; on day 10, 18.7 mmHg; and on day 20, 15.9 mmHg. In Grou p 2, the mean IOP on day 0 was 26.3 mmHg; on day 10, 21.2 mmHg; and on day 20, 16.1 mmHg. Both groups had clinically significant IOP-lowering effect o n day 10 as compared with baseline day (30.2% and 19.4% respectively) (p < 0.01). When dorzolamide was added to latanoprost, the additional IOP reduct ion was 2.8 mmHg (15%) (p < 0.01) compared with 5.1 mmHg (24.1%) (p < 0.01) when latanoprost was added to dorzolamide. No local serious adverse reacti ons were observed. A mild but statistically significant increase in conjunc tival hyperemia was seen in latanoprost applied patients. Conclusions: The results showed that latanoprost and dorzolamide can be combined successfull y to reduce IOP with their additive effects.