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'Tis the season
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Learn to cope with your ragweed allergy
By Martin Rowland, Pharmacist
As ragweed pollen becomes airborne, we inevitably begin looking for quick and safe relief from late season allergy symptoms. Whether you are a first-time or long-time allergy sufferer, reviewing your treatment options with a health-care professional is an important part of effective allergy management.
Allergies triggered by ragweed are the same as the reaction from seasonal allergic rhinitis. Common symptoms include sneezing, runny and/or stuffy nose, and itchy eyes, nose and throat. Less common symptoms include watering eyes, sore throat (be careful — a sore throat which gets worse could be a sign of infection rather than an allergy symptom), headache, poor appetite and wheezing (but wheezing is usually a symptom of another problem, so call your doctor.)
Preventive Measures
Managing your ragweed allergy is possible, and even small changes make a difference, such as:
• Do regular lawn and garden maintenance to discourage ragweed. Hire someone to cut your grass or wear a paper mask and long-sleeved clothes to reduce pollen exposure.
• Stay indoors when you can. Keep car and home windows closed as much as possible, and when possible, use air conditioning instead.
• Wear a hat and sunglasses outdoors to protect eyes from pollen in the air.
• Shower and wash your hair before bedtime to remove pollen and avoid breathing it in at night. Wash pillowcases regularly, but don’t hang clean wash outside to dry—it can collect pollen.
• Pets can carry pollen indoors, so brush them regularly and keep them out of the bedroom.
• Most plants pollinate in the morning, so schedule outdoor activities for later in the day. Pollen levels also tend to be lower when it’s cloudy or after rain.
• Consider taking a vacation in areas relatively free of ragweed, such as western regions of Canada or the United States.
• Some people sensitive to ragweed pollen may also be sensitive to certain foods such as bananas, cantaloupe, watermelon and honeydew (which belong to the same plant family.) Avoid foods that seem to trigger symptoms.
Over-the-counter Antihistamines
According to a recent survey conducted by Decima Research, more than 35 per cent of Canadians suffer from allergies, and the top three concerns about medication are overmedicating (18 per cent), not being able to function normally (17 per cent) and drug interactions (16 per cent).
Drowsiness is the most common side effect of older antihistamines such as diphenhydramine (Benadryl). For this reason most pharmacists and doctors are now recommending that allergy sufferers try a non-sedating newer drug first.
Many antihistamines may have an effect other than on histamine exclusively, which is why they may be more effective in treating symptoms. As well, the lower price tag on some medications can be misleading — some medications require multiple-dosing over a 24-hour period, increasing your daily cost and making it more difficult to take the required number of daily doses which may eventually lead to less effective allergy control.
There are four agents in non-drowsy over-the-counter (OTC) antihistamines — cetirizine (Reactine), loratadine (Claritin), desloratadine (Aerius), and fexofenadine (Allegra) — all which can be used regularly throughout the allergy season.
While these four agents are broadly similar, there are some differences:
• Cetirizine is the major active metabolite of a prescription drug called hydroxyzine. It can act directly following absorption and there are no clinically significant interactions with prescription drugs, OTC medications, antacids or food. Allergy relief can occur in as fast as 20 minutes; however, for some allergy sufferers maximum effectiveness can take up to one hour.
• Desloratadine is an active metabolite of its parent drug, loratadine. It is somewhat more potent than loratadine, but the differences between them are not significant for most people. Onset is over one hour for desloratadine and approximately two hours for loratadine.
• Fexofenadine is the metabolite of terfenadine (Seldane) which was withdrawn from the market because of serious — sometimes fatal — heart rhythm disturbances. Fexofenadine does not demonstrate these same side effects or interactions with other medications or grapefruit juice. Its onset is about one hour. Absorption can be reduced (as much as 42 per cent) if taken within two hours of an antacid, reducing effectiveness and prolonging the treatment period.
If symptoms persist after ragweed season, you could be suffering from perennial rhinitis due to another cause, such as house dust mites. Continuing to take an oral antihistamine may be an option, but again, check with your doctor or pharmacist for recommendations.
If OTC medication does not relieve seasonal or perennial symptoms, call your doctor for prescription treatment — usually a steroid nasal spray would be prescribed, although other options are available.
Martin Rowland is a pharmacist at Queensway Carleton Hospital in Ottawa.
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