The choice of drugs for treatment of allergic rhinitis depends on the severity of symptoms and whether they are intermittent or persistent (see Table 1).

View the Comparison Table: Some Oral Drugs for Allergic Rhinitis

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 years.

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.

View the Comparison Table: Some Oral Drugs for Allergic Rhinitis

Allergic rhinitis can be classified as seasonal, perennial, or episodic. It is often associated with allergic conjunctivitis, rhinosinusitis, and asthma.

H₁-ANTIHISTAMINES — Oral – Oral second-generation H₁-antihistamines are the preferred first-line treatment for relief of the itching, sneezing, and rhinorrhea that characterize mild-to-moderate allergic rhinitis. They are less effective for nasal congestion.

The use of drugs to prevent and control symptoms of allergic disorders can be optimized when patients avoid exposure to specific allergens and/or environmental conditions that trigger or worsen their symptoms.

Allergic rhinitis, allergic conjunctivitis, atopic dermatitis, urticaria, anaphylaxis and asthma (not included here; reviewed in Treatment Guidelines 2008; 6:83) are prevalent worldwide, especially in industrialized countries. Pharmacologic treatment of these disorders continues to improve in efficacy and safety. In addition to using drugs to prevent and control these allergic diseases, patients should be instructed to avoid, if possible, specific allergens and/or environmental conditions that trigger or worsen their symptoms. Allergen-specific immunotherapy may be useful for treatment of allergic rhinitis and allergic conjunctivitis, and in preventing severe insect venom-triggered reactions.

A new formulation of the H1-antihistamine azelastine hydrochloride 0.1% nasal spray (Astepro - Meda) has been approved by the FDA for treatment of seasonal allergic rhinitis (SAR) in patients ≥12 years old and is being heavily advertised to the public on radio, television and the Internet. All azelastine products require a prescription.

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.

Allergic rhinitis, allergic conjunctivitis, atopic dermatitis, urticaria, anaphylaxis and asthma (reviewed in Treatment Guidelines 2005; 3:33 and not included here), are prevalent worldwide, especially in industrialized countries. Pharmacologic treatment of these disorders continues to improve in efficacy and safety. In addition to using drugs to prevent and control the symptoms of their allergic diseases, patients should also be instructed to avoid, if possible, specific allergens and/or environmental conditions that trigger or worsen their symptoms.

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.

Allergic rhinitis, allergic conjunctivitis, atopic dermatitis, urticaria and anaphylaxis, along with asthma (reviewed in Treatment Guidelines 2002; 1:7 and not included here), have increased in prevalence during the past 30 years and are now epidemic worldwide, especially in industrialized countries. Many safe and effective drugs are currently available for prevention and relief of symptoms in these disorders, but pharmacological treatment alone may not be sufficient. Patients should also be instructed to avoid specific allergens or environmental conditions that trigger their symptoms. Allergen-specific immunotherapy, parenteral administration of gradually increasing doses of the allergen ("allergy shots"), has been effective in allergic rhinitis, allergic conjunctivitis and allergic asthma, and also in prevention of anaphylaxis triggered by stings from bees, yellow jackets, hornets and wasps. It has not been effective in food allergy, atopic dermatitis or urticaria.

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.

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.

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.