Some patients with Glaucoma are playing a dangerous game of delaying having their prescriptions filled, all in the name of trying to save money.

According to Alan Robin, MD, associate professor of medicine, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States, up to half of all patients with Glaucoma have to use two medications to achieve the reductions in intraocular pressure that they need. Typically, they would use an agent such as timolol together with a newer more powerful therapy such as latanoprost, a prostaglandin analogue.

In a review of 1784 patients who were using two therapies to treat their glaucoma, Dr. Robin and colleagues found that many would wait until both prescriptions had been exhausted before they would renew either one.

In a poster presentation here on May 5th at the Association for Research in Vision and Ophthalmology Annual Meeting, Dr. Robin said that most patients studied who used latanoprost alone refilled their prescriptions every 41 days, while many of those who used timolol in addition to latanoprost did not refill either prescription until both had been used up.

Refill intervals were longer when any second medication was added, Dr. Robin said, and those longer intervals mean the patient is only receiving half of their treatment.

The situation arises when patients feel the financial pinch and try to make their treatments last just a little bit longer, he said. As a result, they wait until both prescriptions have run out, before refilling either one. Patients delayed refilling their prescription for latanoprost regardless of what adjunct agent was used, according to the researchers.

For example, patients who used latanoprost as monotherapy prescription every 40.6 days, while those who used the drug as part of a combination regimen refilled it every 47.4 days - meaning that they were not getting adequate treatment for approximately 7 days.

If the refill interval was 41.7 days when the latanoprost was used as monotherapy, it increased to 49.5 days when the patient had dorzolamide added to the regimen.

Dr. Robin’s analysis showed that 43% of patients using combination therapy filled their prescription within the first 2 weeks of running out of latanoprost. However, 22.9% waited more than 2 weeks to refill their prescriptions. “That means that almost one-quarter of patients who were supposed to be on combination therapy with one powerful, and one less powerful drug, were actually going for periods of 2 weeks or more where they were only using one drug instead of two, and that they were using the weaker of the two drugs as well, he said.”

Given that tight control over intraocular pressure is the only known way to slow the progression of glaucoma, these patients are putting themselves and their eyes at risk by not refilling their prescriptions as indicated, Dr. Robin said.

Getting glaucoma patients to take their ocular medications as indicated is already a problem in many cases, but that compliance is further upset when the refill interval for one drug is longer than it is for the other.

When adding a second drug to control intraocular pressure, physicians needs to consider the potential impact the addition of that second drug might have on the patient’s adherence to the medical regimen, and the impact it might have on the regimen’ effectiveness, he said.

[Presentation title: Does Adjunctive Glaucoma Therapy Affect Adherence to the Initial Primary Therapy? Poster 2467/B20]