Absence of drying effect makes epinastine a treatment consideration in patients with dry eye

February 15, 2008

Epinastine HCl 0.05% does not have a drying effect on the ocular surface and may be kinder to patients being treated for seasonal allergies and underlying dry eye disease.

Key Points

Norfolk, VA-Epinastine HCl 0.05% (Elestat, Inspire Pharmaceuticals and Allergan) may be kinder to patients being treated for seasonal allergies and underlying dry eye disease because the medication does not have the drying effect on the ocular surface that other drugs might inflict, according to John Sheppard, MD.

He emphasized the pervasiveness of ocular surface disease in his clinical practice experience.

"Ocular surface disease is widespread, under-recognized, and truly the mainstay of every ophthalmology and optometry practice," said Dr. Sheppard, professor, Department of Ophthalmology, Eastern Virginia Medical School, Norfolk, VA, and in private practice in Norfolk. "Ocular surface disease is relevant to emergency medicine, geriatrics, pediatrics, and preoperative and postoperative surgical care. Because of this, the absolute lion's share of ocular surface disease is allergy, dry eye, and blepharitis-with some patients experiencing simultaneously more than one of those conditions. That may be the result of the effects of environment, topical medications, and make-up, among other factors."

"Patients with dry eye and allergy need medications that are appropriate for both conditions," he said.

Olopatadine 0.2% (Pataday, Alcon Laboratories) is beneficial for younger patients with ocular surface disease, and its double concentration applied once daily is well tolerated, Dr. Sheppard said. The launch of this ophthalmic solution has been extremely successful, he said. Its cousin, olopatadine HCl 0.1% (Patanol, Alcon), designed for instillation two times a day, was a "trailblazer" for prescription, anti-allergic topical ocular medications, he added.

Some subsets of patients with allergies, however, have dry eye and blepharitis. Treatment with olopatadine in the context of dry eye may not be optimal because of the strong muscarinic receptor activation and resultant drying effects that this drug has on the mucous membranes, according to Dr. Sheppard. In contrast, epinastine does not have that drying effect, he added.

Dr. Sheppard described a small study of 20 consecutive patients who had itchy eyes from seasonal allergies and complicated by underlying dry eye disease. Ten patients each were assigned to receive olopatadine or epinastine. The drugs were equivalent statistically in the short term in terms of efficacy, signs, and symptoms: everyone experienced relief in the study. There was, however, a significantly lower Schirmer's test in the olopatadine group. This may be reflective of an ocular surface muscarinic effect.

"There was no definite difference in symptoms when [olopatadine] was compared with [epinastine]," Dr. Sheppard said. "However, the lower Schirmer's test in the olopatadine group may suggest that when choosing a drug to treat secondary dry eye and seasonal allergy, epinastine seems to be the better choice."

The study, according to Dr. Sheppard, accomplished what it set out to do in a comparison of the two drugs, and in addition, it may have identified a possible difference in the effect of olopatadine on tear production.

For ophthalmologists treating patients with allergy and underlying ocular surface disease, Dr. Sheppard advised that there may be a wide variety of concomitant ocular surface disease present in one patient. Because of the duality in patients with dry eye and allergies, epinastine is first-line treatment consideration for patients with dry eye, he said.