In October, the company received FDA approval to market its prescription anti-allergy product as an OTC agent. It is the only antihistamine/mast cell stabilizer agent available without prescription, Dr. McDonald noted, and it treats the signs and symptoms of ocular allergy by addressing their pathophysiology rather than just masking the clinical features.
"Persons with red, itchy eyes may seek relief with an OTC product, but many of those marketed for reducing redness contain a decongestant that improves the appearance of the eye by constricting the blood vessels. If used regularly for more than just 3 days, those products can interfere with normal regulation of the blood vessels," said Dr. McDonald, clinical professor of ophthalmology, Tulane University, New Orleans, and a cornea/refractive/ external disease specialist with Ophthalmic Consultants of Long Island, Lynbrook, NY. "Once treatment is stopped, there is a rebound effect with the development of redness that can persist for several days. That problem can promote further use of the vasoconstricting agent or may be so cosmetically displeasing that the affected individual feels compelled to wear sunglasses or avoid appearance in public during that period."
How it works
"Seasonal and perennial allergic conjunctivitis are among the most common causes of red, itchy eyes," she said. "Ketotifen fumarate blocks the pathways for the development of those problems by binding to the H1 receptors and stabilizing mast cells to prevent their release of chemical mediators. It works quickly and for up to 12 hours without any risk of rebound redness or 'abuse' potential."
Ketotifen fumarate demonstrated excellent safety in the clinical trials that led to its original approval as a prescription anti-allergy medication in 1999 as well as during its marketing history. Based on that profile, ketotifen fumarate is something practitioners can feel comfortable recommending as a first-line treatment to patients who might call in and report features consistent with a diagnosis of allergic conjunctivitis, Dr. McDonald said.
"As long as patients are not experiencing problems such as pain or loss of vision that suggest a more serious diagnosis, or an extreme case, it is reasonable to suggest a trial of ketotifen fumarate," she said. "However, patients should be instructed to come in to the office if they do not have a response to that treatment or if they develop more serious findings."
Parents also may use ketotifen fumarate for their children with signs and symptoms related to ocular allergy. It is the only OTC treatment approved for use in children as young as 3 years.
As another convenience feature, Dr. McDonald said, is that ketotifen fumarate requires only twice-daily administration because its anti-allergy effects can last up to 12 hours. Some other OTC products for ocular allergy are recommended to be administered multiple times per day because they provide much shorter term relief of only 3 to 4 hours.
"It is often argued whether a once-a-day medication has a major advantage for better compliance than something that must be used twice a day," she said. "My feeling is that compliance is enhanced once the administration frequency is reduced to the point where patients don't have to carry the medication with them, and a twice-daily agent meets that criterion."
Ketotifen fumarate also is comfortable on instillation, she said, although patients who wear contact lenses should be reminded to wait 10 minutes after putting in the medication before they insert their contact lenses.