What Allergy Medications Are Available?

Tis the season for general discomfort due to seasonal allergies. One can look forward to any number of symptoms inclusive of sneezing, coughing, wheezing, itchy eyes, and more. As the Spring season returns, our plant life will resume sprout growth, and the pollen count will rise in tandem eliciting our allergic response. Interestingly enough, tree pollen accounts for 75-90% of the annual pollen production with weeds and grass pollen producing the remainder; however, only a small percentage of tree pollen is considered to be aeroallergenic. Allergic rhinitis is the most common allergic disease affecting about 40 million Americans and is just one of the many diseases that are exacerbated through the changing climate.

Illustration of PollenPathophysiology

Our body has mechanisms of defense to protect us from injury and infection. Some people’s bodies are so protective, that they respond to otherwise non-harmful stimuli these are what we call hypersensitivities.

The majority of seasonal allergies are IgE mediated hypersensitivities. IgE is an antibody produced by immune cells called B cells that have switched into antibody producing plasma cells. The antigen, pollen for this example, enters our body, and is recognized as a foreign invader by our immune system, then through an extensive cascade of cellular communication, B cells are turned into IgE producing factories. Upon the further exposure to pollen, IgE stimulates mast cells to release a plethora of products including histamine. Mast cells are found in loose connective tissue close to blood vessels such as the skin, gastrointestinal tract, and respiratory tract: three common places where we experience symptoms of seasonal allergies. Through the release of this histamine and other chemicals, we experience symptoms such as sneezing, swelling, increased mucus production, wheezing, and/or difficulty breathing.

Available Over the Counter Treatments

Oral Decongestants

Pseudophedrine or phenylephrine work by constricting the blood supply to the nasal mucosa, thereby decreasing the blood flow, and swelling or edema. This helps to relieve the congested feeling allowing for easier breathing through the nose, but because of the vasocontricting nature of these medications, should be limited in use by persons with high blood pressure or other cardiovascular complications, and alternative therapies should be considered such as an intranasal decongestant phenylephrine. Do not take any form of phenylephrine if you have BPH, as this medication may exacerbate urinary retention.

Spray Decongestants

Oxymetazoline is an imidazoline vasoconstrictor that works in a similar fashion as pseudophedrine to reduce edema in the nasal mucosa: making it easier to breath through your nose.  It provides near immediate relief from congestion, and is a suitable alternative for those with cardiovascular issues.  Oxymetazoline can be found in Afrin® products and Vicks Sinex®. Should not be used for more than a 3 day period and should be limited in use to 2-3 sprays in each nostril twice daily.

Oral Antihistamines

Loratadine is the active ingredient in Claritin®, Clear-Atadine®, Tavist® Non Drowsy, and Alavert®. This active ingredient belongs to a class of medications known as antihistamines; more specific, a long acting, tricyclic piperidine. Loratadine containing medications selectively block peripheral histamine H1-receptor activity. This can lead to relief from urticaria or hives, allergic rhinitis, and other seasonal allergy symptoms. Usually this medication takes between 1 to 3 hours to start working, but if you do not experience relief, do not take another dose. You should not take more than 10mg of loratadine a day. If this medication does not begin to work within a couple days, an alternative therapy should be sought.

Fexofenadine is another oral antihistamine and is similar in class to loratadine. Fexofenadine is a piperidine derivative and is the active metabolite of terfenadine. This is the active ingredient in Allegra® products which have low potential for drowsiness. It usually takes about 60 minutes to start working, but this can be negatively affected by consumption with fruit juices: grapefruit, orange, and apple juice as they interact with the medicine and lower its effect.

Cetirizine is an oral antihistamine belonging to a slightly different class called piperazine. This class of medications can cause drowsiness and/or fatigue, however is not contraindicated with other medications and thus can be taken in a number of different scenarios. Cetirizine is the active ingredient in Zyrtec® products and is a metabolite of hydroxyzine, a prescription only medication which is highly sedating. Its effects should be seen under an hour, but this can be delayed if taken with food as this will interfere with the drugs proper absorption. The duration of action for cetirizine is 24 hours and you should not take more than 10mg per 24 hours.

Diphenhydramine may be the most versatile antihistamine for relief of allergy symptoms, but consideration should be given to the time when you will take this as it can be highly sedating. Some people may not experience sedation but stimulation/excitation and should probably seek an alternative antihistamine therapy. Diphenhydramine is the active ingredient in Benadryl® for antihistamine effects, but can also be found in sleep aids like Sominex®. The onset of action for diphenhydramine is about 15-30 minutes and lasts for about 4-6 hours. You should not drink alcohol while taking this medication.

Alternative (Non-Pharmacologic) Therapies

Avoid environmental triggers such as cigarette smoke, air pollution, pet dander, etc.  Ensure that you get adequate rest and remain properly hydrated.

Nonpharmacologic therapy can include the use of a saline nasal spray 2-3 times daily and or nasal irrigation with saline which have both demonstrated symptomatic relief from congestion.

Steam therapy has been shown to be effective to relief mild symptoms of congestion.

No clinically significant evidence has proven the use of mentholated preparations to be successful in providing relief, but they can do no harm if used properly and some people do find great results from using them.

For eye relief cold or warm compresses can be used to provide relief from soreness, red inflamed eyes, and itchy eyes.

By:

Jeremy KW Spiewak, Pharmacy Intern, CPhT, MA RPhT, BA Chemistry, Doctor of Pharmacy Candidate at Massachusetts College of Pharmacy and Health Sciences

In The News

Levoxyl® Voluntarily Recalled at the Pharmacy Level

Pfizer has conducted a careful risk assessment and has determined that there is little to no risk of any adverse health events due to this packaging defect.  Regardless, Pfizer, King, and the FDA have worked together and decided to voluntarily recall at the pharmacy level, all Levoxyl strengths.

Click Here to Read More

Further Reading:

EPA: Allergies Getting Worse?

Pollen Allergy Forecast - Enter your zip code to check the levels in your area

References:

Alternative to Pseudophedrine. Detail Document 210908. Pharmacist’s Letter v 21(9). Stockton, CA: Therapeutic Research Company, 2005.

Cetirizine. Micromedex 2.0® [online]. 2013. Available through Truven Health Analytics, Inc. Accessed April 2013.

Comparison of Antihistamines. Detail Document 240707. Pharmacist’s Letter v 24(7). Stockton, CA: Therapeutic Research Company, 2008.

Diphenhydramine HCl. Micromedex 2.0® [online]. 2013. Available through Truven Health Analytics, Inc. Accessed April 2013.

Fexofenadine HCl. Micromedex 2.0® [online]. 2013. Available through Truven Health Analytics, Inc. Accessed April 2013.

Loratadine. Micromedex 2.0® [online]. 2013. Available through Truven Health Analytics, Inc. Accessed April 2013.

Kalish, Richard M. (1995) Antigen Processing: The Gateway to the Immune Response. Journal of the American Academy of Dermatology, 32:4, pp640-652.

McCance, Kathryn L., Huether, Sue E.. Pathophysiology: The Biologic Basis for Disease in Adults and Children. Fifth Ed., Elsevier Mosby, St. Louis MO, 2006.

Sinusitis: Nonpharmacologic Therapy. Clin-eguide® [online]. 2013. Available through Wolters Kluwer Health, Inc. Accessed April 2013.

U.S. EPA. A Review of the Impact of Climate Variability and Change on Aeroallergens and Their Associated Effects (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-06/164F, 2008.


Original Published:April 2013

Revised:April 2013