The FDA has approved the marketing of loratadine (Claritin - Schering), a second-generation H₁-antihistamine, without a prescription. The drug was also recently approved for OTC use as Alavert (Wyeth) and other generics are expected.

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.

Fexofenadine (Allegra, and others) is the most recent second-generation H₁-antihistamine to become available over the counter (OTC). Cetirizine (Zyrtec, and others) and loratadine (Claritin, and others) are already available OTC. Cetirizine can be sedating in usual doses. Loratadine can be sedating in higher-than-usual doses. Fexofenadine remains nonsedating even in higher doses.

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.

View the Comparison Table: Some Oral Drugs for Allergic Rhinitis

With the coming of spring, direct-to-consumer (DTC) advertisements in newspapers, in magazines and on television are urging people with seasonal allergies to ask their doctors about one or another of the newer, non-sedating antihistamines.

Levocetirizine (Xyzal - UCB/Sanofi-aventis), the active enantiomer of the second-generation H₁-antihistamine cetirizine (Zyrtec), has been approved by the FDA for treatment of seasonal and perennial allergic rhinitis (SAR and PAR) and chronic idiopathic urticaria in adults and children 6 years of age and older. Cetirizine has been approved by the FDA for over-the-counter use and may also become available generically in the US. Levocetirizine has been available in Europe since 2001.

Loratadine (Claritin - Schering), a new H 1 -receptor antagonist, has been approved by the U.S. Food and Drug Administration for treatment of seasonal allergic rhinitis in patients more than 12 years old. It will compete with older, relatively sedating drugs such as chlorpheniramine (Chlor-Trimeton, and others) and clemastine (Tavist - Medical Letter, 35:9, 1993) and with newer relatively non-sedating agents such as terfenadine (Seldane) and astemizole (Hismanal).

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.

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.