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.

Cetirizine (Zyrtec - Pfizer), a histamine H 1 -receptor antagonist, has been approved by the US Food and Drug Administration for treatment of seasonal allergic rhinitis, perennial allergic rhinitis and chronic idiopathic urticaria in adults and children more than 12 years old.

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).

Advertisements for clemastine (Tavist-1 - Sandoz), an ethanolamine oral antihistamine, have recently appeared on television and in major newspapers in the USA. Clemastine is an old drug (Medical Letter, 21:24, 1979) that has now become available without a prescription.

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.

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.

The FDA has approved Acuvue Theravision with Ketotifen (Johnson & Johnson Vision Care), a daily-wear, disposable, vision-correcting soft contact lens that releases the H₁-antihistamine ketotifen, for prevention of ocular itch due to allergic conjunctivitis in contact lens users. This is the first approval for a drug-eluting contact lens. Ketotifen eye drops (Alaway, Zaditor, and others) are available over the counter.

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.

Quzyttir (TerSera), an IV formulation of the second-generation H1-antihistamine cetirizine, has been approved by the FDA for treatment of acute urticaria in patients ≥6 months old. Oral formulations of cetirizine (Zyrtec, and others) have been for sale over the counter for years. Quzyttir is the first parenteral formulation of a second-generation H1-antihistamine to become available in the US; parenteral formulations of two first-generation H1-antihistamines, diphenhydramine (Benadryl, and others) and hydroxyzine (Vistaril, and others), have been available for many...

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.