Effect of Changing Medication Regimens in Glaucoma Patients

Abstract

When glaucoma medication fails to adequately control intraocular pressure (IOP), a second medication is frequently added. Before adding a second drug to patients whose IOP was no longer controlled by 0.5% timolol, we tested the effect of switching to another beta blocker, levobunolol (0.5 or 1%). We also evaluated the effect of study participation on compliance in the control group continuing to receive 0.5% timolol. In each treatment group, the IOP of approximately 30–40% of the patients was successfully controlled for the 3-month study period. The remaining patients did not exhibit significant pressure reductions and were dropped from the study within 2 weeks. We concluded that (1) the results of’switch’ studies without a control group must be interpreted carefully, and (2) the initiation of a ‘new regimen’ with an equieffective beta blocker may be sufficient to increase compliance and thereby control IOP.

Ocular hypotensive efficacy of travoprost in patients unsuccessfully treated with latanoprost

“…In a double-masked, controlled study comparing patients who had not reached target IOP levels on timolol changed to either timolol again, or levobunolol (another β-adrenoceptor antagonist), the overall mean IOP reduction in the patients completing all 3 months of the study was approximately 0.4 mm Hg 29 . In another openlabel study in which patients using dorzolamide were changed to receive brinzolamide (another topical carbonic anhydrase inhibitor), the mean IOP reduction was approximately 0.8 mm Hg 30 .…”

TFOS DEWS II Clinical Trial Design Report

“…In contrast to a placebo, a "nocebo" is a maneuver, instruction, or substance that inherently does not worsen the condition nor provoke an adverse event, but which the patient interprets as aggravating the condition being treated or producing an unwanted adverse event. Foulks hypothesized that one possibility for the large placebo response seen in DED trials is that such a placebo response may be due to improved compliance in using the prescribed medication by patients enrolled in a clinical trial (i.e., a "Hawthorne Effect") [73,74]. Another consideration is that, if patients prior to enrollment in a clinical trial were using preservative-containing lubricants or other topical medications, and then discontinued their use for the trial, improvement in symptoms and ocular surface staining may be due to recovery from adverse effects of the preservative.…”

Predictors of additional intraocular pressure reduction in patients changed to latanoprost/timolol fixed combination

“…Findings of six studies [36-41] in which one group or eye continued on the baseline ocular hypotensive therapy while the other group or eye switched to another agent for periods ranging from 21 days to 6 months are inconsistent with regard to the potential magnitude of such an effect. Effect sizes ranged from -0.37 mmHg in 115 patients continued for 6 months on dual therapy that included a beta-blocker [40] to -3.1 mmHg in five patients continued for 12 weeks on timolol [38]. Mean IOP reductions in the control group in each of these six studies were substantially smaller than the -5.4 mmHg mean change from baseline to week 12 observed herein.…”