This article is more than 5 years old. Information may no longer be current.
Did you ever wonder … will we always treat glaucoma with pressure eye drops?
Other options with alternative dosing mechanisms may be the answer for patients who do not use their drops consistently.
We are fortunate to practice at a time when we have many wonderful medication options to offer our patients with glaucoma.
In general, medications offer effective IOP lowering with a low risk of side effects. However, the risk of side effects is real and compliance/adherence are significant factors to the success of medical management.
|
|
The greater the number of bottles prescribed and the greater the frequency of dosing, the more difficult it is for a patient to adhere to a prescribed regimen. Most anti-glaucoma medications are formulated as eye drops, not because they are easier to take, but simply to deliver higher concentrations of the active agent to the anterior segment with less systemic adsorption (in an appropriate attempt to minimize complications).
As we all know, self-administration of eye drop medication requires a certain amount of dexterity, coordination and luck. Often, there is a lot of waste as our patients attempt to “zero in” on the target. This is evidenced by the disconnect between claims by manufacturers and insurance companies about each bottle containing a nearly 6-week supply of medication, and the knowledge that our patients often have trouble making the medications last for the allotted 1 month.
Alternative dosing strategies
A new molecule, anecortave acetate, has a novel dosing mechanism — anterior juxtascleral depot injections.
|
|
OSN Glaucoma Section Member Alan L. Robin, MD, said, “Not only is the molecule novel, but the concept of an insertion of a depot of a medication in the sub-Tenon’s space is novel.
“Recent studies have found that adherence to glaucoma medications is a major problem among all patients, especially those with glaucoma. Additionally, those who have more advanced disease have trouble getting drops into their eyes. Almost 20% of patients are reliant upon others to administer their eye drops,” Dr. Robin said.
At the American Academy of Ophthalmology meeting, Dr. Robin discussed some of his pilot data. After a single depot of anecortave acetate, six out of eight patients experienced a sustained IOP-lowering effect lasting at least 6 months.
In an era where a leading cause of blindness, wet macular degeneration, is treated with monthly intravitreal injections, periodic sub-Tenon’s dosing may not seem outlandish.
The sub-Tenon’s route of administration may not be appropriate or accepted by every patient, but if the IOP-lowering effectiveness of this molecule is eventually validated in multicenter studies, it opens up another potential option for patients who are unable to effectively administer topical eye drops or those who are not compliant.
Another potential treatment on the horizon is memantine hydrochloride (Namenda, Forest Pharmaceuticals).
|
Image: Robin AL |
|
Allergan is conducting two phase 3 clinical trials to assess the effect of systemic memantine in people with elevated IOP. If the phase 3 trials show an ability to delay or halt glaucomatous visual field or optic nerve progression, it would be the first IOP-independent treatment for glaucoma.
As an oral medication, memantine could prove to be more convenient for patients. It is hoped that the results may be available in 2007.
To date, lowering of IOP is the only rigorously proven treatment for glaucoma. Traditionally, most patients are initially managed by topical eye medications. However, the traditional paradigm may change as more options are proven safe and effective for our patients.
For more information:
- Douglas J. Rhee, MD, is an assistant professor of ophthalmology at Harvard Medical School and on the faculty of the Massachusetts Eye and Ear Infirmary. He can be reached at 243 Charles St., Boston, MA 02144; 617-573-3670; fax: 617-573-3707; e-mail: dougrhee@aol.com. Dr. Rhee has no financial interest in memantine or anecortave. He is on the speakers bureau for Alcon, Allergan and Merck. Dr. Rhee received grant support from Allergan and Pfizer. He is a consultant for Johnson & Johnson.
- Alan L. Robin, MD, is a professor of ophthalmology at the University of Maryland and associate professor of ophthalmology at Wilmer Eye Institute, Johns Hopkins University. He can be reached at 6115 Falls Road, Suite 333, Baltimore, MD 21209; 410-377-2422; fax: 410-377-7960; e-mail: arobin@glaucomaexpert.com. Ocular Surgery News could not confirm whether Dr. Robin has a direct financial interest in the products mentioned in this article or if he is a paid consultant for any companies mentioned.
- Forest Pharmaceuticals Inc., maker of Namenda (memantine hydrochloride), can be reached at 13600 Shoreline Drive, St. Louis, MO 63045; 314-493-7000; Web site: www.forestpharm.com