Intraocular Pressure–Lowering Effect of Adding Dorzolamide or Latanoprost to Timolol: A Meta-analysis of Randomized Clinical Trials
Received 20 December 2005; accepted 4 July 2006. published online 27 October 2006.
Objective
To estimate the intraocular pressure (IOP)–lowering effect of 2% dorzolamide or 0.005% latanoprost when added to 0.5% timolol.
Design
Meta-analysis of randomized clinical trials.
Participants
Seventeen articles reporting on 19 study arms with 5 possible treatment combinations and 4 study arms serving as controls.
Methods
Articles written in English, German, French, or Dutch and published up to December 2004 were identified in Medline, Embase, the Cochrane Controlled Trials Register, and references from relevant articles. For the article to be considered, over 85% of the patients had to have primary open-angle glaucoma or ocular hypertension. The pooled 1- to 3-month additional IOP-lowering effect after a run-in phase on timolol was calculated by performing meta-analysis using the random effects model.
Main Outcome Measures
Absolute and relative changes in IOP after run-in on timolol for peak moment, trough moment, or mean diurnal curve.
Results
The pooled change from baseline [mean (95% confidence interval)] for 0.5% timolol varied from −0.7 mmHg (−1.2 to −0.2, for the mean diurnal curve) to −2.0 mmHg (−1.3 to −2.7, at peak). Pooled changes for 2% dorzolamide in concomitant use with 0.5% timolol were −4.1 mmHg (−4.4 to −3.8) at trough and −4.9 mmHg (−5.3 to −4.5) at peak. The fixed 2% dorzolamide and 0.5% timolol combination resulted in a pooled change of −3.8 mmHg (−4.2 to −3.4) at trough and −4.9 mmHg (−5.3 to −4.5) at peak. The concomitant use of 0.005% latanoprost and 0.5% timolol gave a pooled change from baseline of −6.0 mmHg (−6.8 to −5.2) at the mean diurnal curve. The fixed combination of 0.005% latanoprost and 0.5% timolol resulted in a mean change of −3.0 mmHg (−3.8 to −2.2) at the mean diurnal curve.
Conclusion
In this meta-analysis of clinical trials, the addition of dorzolamide or latanoprost further lowers IOP in eyes on timolol. This result may not be generalizable because these trials may have included nonresponders to timolol.
1Department of Ophthalmology, Maastricht University Hospital, Maastricht, The Netherlands.
2Department of Epidemiology, Maastricht University, Maastricht, The Netherlands.
3Department of Public Health and Epidemiology, Medical School, University of Birmingham, Birmingham, United Kingdom.
4Comprehensive Cancer Institute Limburg, Department of General Practice, Catholic University of Leuven, Leuven, Belgium.
Reprint requests to C. A. B. Webers, MD, PhD, Department of Ophthalmology, Maastricht University Hospital, PO Box 5800, 6202 AZ Maastricht, The Netherlands.
Manuscript no. 2006-12.
Financial support: Dutch Health Care Insurance Council, Diemen, The Netherlands.
No author has any commercial (proprietary or financial) interest in any drug mentioned in the article.
ABSTRACT