Antihistamines and decongestants are standard for treating allergies, but they're not the only game in town. New drugs on the market and in development target different molecular mechanisms in the production of allergy symptoms.
Decongestants constrict blood vessels in the nose, shrinking nasal tissues. Antihistamines block the receptors for histamine, reducing production of mucus. Other molecules important in the allergic response include leukotrienes, IgE, and phosphodiesterase-4. Three new classes of allergy drugs are based on research into the role of these molecules.
Leukotriene receptor antagonists. Montelukast (brand name Singulair) is already approved for allergies as well as asthma. This is a once-a-day pill. A recent medical article reports that it improves quality of life for most patients, either alone or in combination with antihistamines. Side effects include gastrointestinal symptoms, fatigue, fever, stuffy nose, cough, flu, upper respiratory infection, dizziness, headache, and rash.
Anti-IgE antibodies. Omalizumab (brand name Xolair) is a recombinant humanized monoclonal antibody which binds to the immunoglobulin E (IgE) molecules which play a key role in allergic reactions. This injectable biologic drug is approved in the United States for treatment of allergic asthma. It is currently in clinical trials for seasonal allergies, peanut allergy, milk allergy, cat dander allergy, allergic rhinitis, atopic dermatitis, and urticaria (skin rash). A Japanese study demonstrated that omalizumab is effective in treating seasonal allergies to Japanese cedar pollen. Side effects include injection site reactions, viral infections, upper respiratory tract infection, sinusitis, headache, sore throat, and rare cases of anaphylaxis. The cancer rate was slightly elevated for patients receiving omalizumab in clinical trials: 0.5 percent for the drug, compared to 0.2 percent for placebo.
Phosphodiesterase-4 (PDE4) inhibitors. This is a more speculative approach to allergies. I found one clinical trial in progress for roflumilast (brand name Daxas) for allergies. The drug is not yet approved for any use in the United States, but has shown promising results for chronic obstructive pulmonary disease.
Check with your doctor for the latest results on these new drugs.
References:
Ciebiada M et al, “Quality of life in patients with persistent allergic rhinitis treated with montelukast alone or in combination with levocetirizine or desloratadine”, J Investig Allergol Clin Immunol 2008; 18(5): 343-49.
Singulair (montelukast) web site:
http://www.singulair.com/montelukast_sodium/consumer/allergies/allergy-treatment/adult-allergy-medication.jsp?WT.svl=1
Okubo K et al, “Omalizumab is effective and safe in the treatment of Japanese Cedar Pollen-induced seasonal allergic rhinitis”, Allergology International. 2006; 55: 379-86.
Xolair (omalizumab) web site:
http://www.xolair.com
Spina D, “PDE4 inhibitors: current status”, British Journal of Pharmacology 2008; 155: 308-15.
Clinical trials:
www.clinicaltrials.gov
Linda Fugate is a scientist and writer in Austin, Texas. She has a Ph.D. in Physics and an M.S. in Macromolecular Science and Engineering. Her background includes academic and industrial research in materials science. She currently writes song lyrics and health articles.