Assessment of ocular hypotensive effect and safety 12 months after changing from an unfixed combination to a latanoprost 0.005% + timolol maleate 0.5% fixed combination

Kenji Inoue¹, Ryoko Okayama¹, Risako Higa¹, Masato Wakakura¹, Goji Tomita^2
1Inouye Eye Hospital, 4-3 Kanda-Surugadai, Chiyoda-ku, ²Second Department of Ophthalmology, Toho University School of Medicine, Meguro-ku, Tokyo, Japan

Background: Latanoprost 0.005% + timolol maleate 0.5% combined eyedrops were recently made available in Japan. We prospectively investigated the intraocular pressure (IOP)-lowering effect, visual preservation effect, and adverse reactions of a one-year administration of this fixed combination.
Methods: The subjects included 162 eyes from 162 patients diagnosed with either primary open-angle glaucoma or ocular hypertension and using an unfixed combination of latanoprost 0.005% and timolol maleate 0.5%. The unfixed combination was discontinued and replaced with the latanoprost 0.005% + timolol maleate 0.5% fixed combination with no washout period. IOP was measured before (baseline) and 3, 6, 9, and 12 months after the change. The mean deviation value of Humphrey field analysis was compared. Adverse reactions were examined at every follow-up.
Results: No significant differences were found between mean IOP values obtained at baseline (mean ± standard deviation, 15.2 ± 3.3 mmHg) 3 months (15.1 ± 3.2 mmHg), 6 months (15.3 ± 3.1 mmHg), 9 months (15.3 ± 3.1 mmHg), and 12 months (15.1 ± 3.2 mmHg) after the change from the unfixed to the fixed combination of eyedrops (P = 0.212). In addition, no significant differences were observed between mean deviation values obtained at baseline (–9.11 ± 6.94 dB) and 12 months (–10.08 ± 7.24 dB) after the change (P = 0.114). Thirty-one patients discontinued the fixed combination within 12 months of replacement, due to an insufficient IOP decrease (20 patients, 12.3%) and adverse reactions (11 patients, 6.8%).
Conclusion: Following replacement of two eyedrop medications (latanoprost 0.005% and timolol maleate 0.5%) by one fixed combination (latanoprost 0.005% + timolol maleate 0.5%), IOP and visual field were preserved. However, 20% of the patients discontinued the new treatment because of an insufficient IOP decrease and complaints of adverse reactions.

Keywords: latanoprost 0.005%, timolol maleate 0.5%, fixed combination, intraocular pressure, safety, visual field