Olopatadine hydrochloride (Patanol - Alcon), a propilidinedibenzoxypin derivative, has recently been marketed in a 0.1% ophthalmic solution for prevention of itching due to allergic conjunctivitis in adults and children more than three years old. It is the first drug for this indication that both inhibits mast cell degranulation and is a selective histamine H1 receptor antagonist (NA Sharif et al, J Pharmacol Exp Ther, 278:1252, 1996).

Epinastine HCl, an H₁-receptor antagonist and mast cell stabilizer, has been approved by the FDA for use in a 0.05% ophthalmic solution (Elestat - Allergan/Inspire) for prevention of itching associated with allergic conjunctivitis. The drug is available orally in Europe and Asia.

Olopatadine 0.6% nasal spray (Patanase - Alcon) has been approved by the FDA for treatment of seasonal allergic rhinitis in patients ≥ 12 years old. An H1-antihistamine with mast-cell stabilizing activity, olopatadine is already marketed for treatment of allergic conjunctivitis in a 0.1% solution as Patanol and in a 0.2% solution as Pataday. Azelastine (Astelin), another H1-antihistamine with mast-cell stabilizing activity, has been available for intranasal treatment of allergic rhinitis since 1997.

Ophthalmic formulations of ketotifen fumarate (Zaditor), pemirolast potassium (Alamast) and nedocromil sodium (Alocril) have recently been approved by the FDA for use in adults and children with itching of the eyes due to allergic conjunctivitis.

Bepotastine besilate 1.5% ophthalmic solution (Bepreve - ISTA Pharmaceuticals), an H₁-antihistamine, has been approved by the FDA for topical treatment of itching associated with allergic conjunctivitis in patients ≥2 years old. Bepotastine was first developed in an oral systemic formulation and has been used as such for treatment of allergic rhinitis in Japan.

The ophthalmic H1-antihistamine alcaftadine 0.25%, which has been available by prescription since 2011 for use in patients with allergic conjunctivitis, is now available without a prescription as Lastacaft Once Daily Relief (Allergan) for temporary relief of itchy eyes due to pollen, ragweed, grass, animal hair, and dander in adults and children ≥2 years old. It is the third ophthalmic antihistamine to be approved for over-the-counter (OTC) use (see Table 1).

Alcaftadine (Lastacaft – Allergan), an ophthalmic H₁-antihistamine, has been approved by the FDA for prevention of itching associated with allergic conjunctivitis in patients > 2 years old.

Patients with seasonal allergies often experience nasal itching and congestion, sneezing, rhinorrhea, and itchy, watery eyes. Oral, intranasal, and ophthalmic preparations are widely available over the counter (OTC) for relief of symptoms. Prescription products for management of allergic rhinitis and allergic conjunctivitis are reviewed separately.

A 0.24% ophthalmic solution of the second-generation H₁-antihistamine cetirizine (Zerviate – Eyevance) is now available by prescription for treatment of ocular itching associated with allergic conjunctivitis in patients ≥2 years old. Oral cetirizine (Zyrtec, and others), which is used for treatment of allergic conjunctivitis and rhinitis, has been available over the counter (OTC) for years.

Initial treatment of allergic rhinitis (AR) depends on the severity of symptoms and whether they are intermittent or persistent (see Table 1).