Montelukast (Singulair - Merck) is an oral cysteinyl leukotriene D₄ receptor antagonist originally marketed for treatment of asthma. It was approved by the FDA in 2003 for treatment of seasonal allergic rhinitis and recently for use in perennial allergic rhinitis in adults and children ≥ 6 months old. Intranasal corticosteroids have generally been considered the most effective drugs available for prevention and treatment of allergic rhinitis.

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.

Azelastine hydrochloride, a histamine-H1 receptor antagonist, has been marketed as a 0.1% nasal spray (Astelin - Wallace) for treatment of seasonal allergic rhinitis. Corticosteroid and cromolyn sodium nasal sprays are also available for this indication (Medical Letter, 37:5, 1995). Cromolyn sodium (Nasalcrom) has now been approved for over-the-counter use.

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).

View the Comparison Table: Some Oral Drugs for Allergic Rhinitis

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.

Montelukast (Singulair - Merck), a leukotriene receptor antagonist already marketed for asthma (Treatment Guidelines from The Medical Letter 2002; 1:11), has been approved by the FDA for treatment of seasonal allergic rhinitis in adults and children more than 2 years old.

Desloratadine (des lor at' a deen; Clarinex - Schering), an active metabolite of the H1-receptor antagonist loratadine (Claritin), has been approved by the FDA for oral treatment of allergic rhinitis and chronic urticaria in patients at least 12 years old. The patent for loratadine expires in December 2002, and generic or over-the-counter versions are expected.

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.

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