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).

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.

The FDA has approved Ryaltris (Hikma), a fixed-dose combination nasal spray containing the H1-antihistamine olopatadine hydrochloride (Patanase, and generics) and the corticosteroid mometasone furoate (Nasonex 24 HR Allergy, and generics), for treatment of seasonal allergic rhinitis symptoms in persons ≥12 years old. Ryaltris is the second intranasal antihistamine/corticosteroid combination to be approved for this indication; azelastine 0.1%/fluticasone propionate (Dymista, and generics), which is approved for use in persons ≥6 years old, was the first. Both products are available...

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.

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).

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.

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.

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.

The FDA has approved a nasal spray fixed-dose combination (Dymista – Meda) of the H₁-antihistamine azelastine (Astelin, Astepro, and generics) and the corticosteroid fluticasone propionate (Flonase, and generics) for treatment of seasonal allergic rhinitis (SAR) in patients ≥12 years old who need both medications for symptomatic relief. It is the first nasal spray to be approved in the US that contains both an H₁-antihistamine and a corticosteroid.

The 0.15% nasal spray formulation of the H₁- antihistamine azelastine hydrochloride (Astepro Allergy; Children's Astepro Allergy – Bayer) is now available over the counter (OTC) for temporary relief of nasal congestion, runny nose, sneezing, and itchy nose due to allergic rhinitis in adults and children ≥6 years old. It is the first intranasal antihistamine to be approved by the FDA for OTC use. Other drugs that are available OTC for treatment of allergic rhinitis symptoms include oral antihistamines, intranasal corticosteroids, and mast cell stabilizers.