ANTIHISTAMINES AND ALLERGIC RHINITIS

Apr 5, 2016

By Kevin Shewchuk, Pharmacist at the Dauphin Clinic Pharmacy

One of the nice people at CKDM that record me and make me sound smart is Alec Woolston. A little while ago, I heard him lamenting on air that people often got his name wrong. He is often called Alex instead of Alec. Even University Profs who had his name written properly in front of them got his name wrong. I can sympathize. People often get my name wrong too. My first name is Trevor. People seem to get that wrong a lot. The interesting part is how they get it wrong. I don't get called Travis or Trent or Terry. I get called Kevin. Very, very consistently - Kevin. My mom still tells the story of parent teacher interviews she went to when I was in Kindergarten. My Kindergarten teacher kept telling her that Kevin was doing well, although he was slow to finish his work and easily distracted. And it is remarkable how my misnomer has remained constant through the years. People I have met through work call me Kevin. People I have played rec hockey with call me Kevin. And it always seems to be Kevin.

Maybe my parents should have named me Kevin. Maybe Shakespeare was right that names aren't that important. Is a rose by any other name, Kevin. Speaking of roses, spring is here. We finally get to go outside. We are loving the longer hours of sunlight. We want to walk, ride our bikes and play in the garden. However, with spring comes pollen. Spring pollens mean itchy watery eyes and stuffed up noses for many people. We call this condition allergic rhinitis. The usual quote is that about 10% of the population has hay fever or allergic rhinitis. However, some estimates peg the number closer to 30-40%.

If we look inside the nose of someone with allergic rhinitis, there is a lot going on. Allergens, in this case pollens, are inhaled and bind to an antibody called IgE on the surface of special immune system cells called mast cells. These mast cells live in the lining of the nose, which is called the nasal mucosa. After exposure to the allergens, mast cells quickly release a bunch of chemical signals. These signals include histamine, tryptase, vascular endothelial growth factor, and other inflammatory mediators. This leads to nasal itching and sneezing. Leukotrienes increase vascular permeability, causing runny nose and congestion. Then, 4 to 12 hours later, nasal congestion is increased due to the influx of different immune cells called T-cells, basophils, and eosinophils. These cells then release their own batch of chemical messengers.

Allergic rhinitis is when the immune system over reacts to pollens, which really aren't a threat. The best way to avoid allergy symptoms would be to avoid the pollen. Some tips include using air conditioning instead of opening windows, showering and changing clothes after being outdoors and use a clothes dryer rather than hanging linens outside to dry. Frankly, though, if you go outside, you will probably be exposed. If you get allergic rhinitis, the most common over the counter medications we reach for are the antihistamines. Antihistamine medications block the histamine receptor which hopefully stops the allergic cascade and reduces the allergic rhinitis symptoms.

There are two basic types of medications that block the H1 histamine receptor. We call these the first and second generation antihistamines. The first generation antihistamines are have names like chlortripolon (chlorpheniramine), and benadryl (diphenhydramine). They are inexpensive, work quite well, but they also often cause drowsiness, and some other side effects like urinary retention, and worsening glaucoma. They work fast, which is great if you have an itchy rash, but they don't last that long and so if you have allergic rhinitis, you may have to take several pills a day. So, they are cheap and fast, but have no staying power and might put you to sleep. Thus, they aren't usually the first choice for allergic rhinitis.

Second generation antihistamines cause much less sedation, have far fewer side effects, but they are more expensive. These are agents like reactine (cetirizine), and claritin (loratadine). A nice benefit is one pill often lasts all day. Reactine is good for both runny noses and itchy rashes, but I have seen it occasionally make some people sleepy. Claritin only works well on runny noses, but it is much less likely to make someone sleepy. Between the two, I usually recommend the Claritin or loratidine for allergic rhinitis.

Now we have another allergic rhinitis option available without a prescription. Recently the steroid nasal spray, triamcinolone or Nasacort became available without a prescription. Nasal steroids work better than oral antihistamines on runny nose, stuffy congested noses, sneezing and nasal itch. They work as well as oral antihistamines on itchy red eyes. Nasal steroid sprays definitely won't make you sleepy. Nasal steroids are quite safe, but there are some cautions to keep in mind. Steroids suppress the immune system, so shouldn't be used if you had a bacterial, virus or fungal infection, especially in your nose. Nasal steroids can accidentally get sprayed in the eye, so shouldn't be used if you have glaucoma or cataracts. Talk to your pharmacist if you take asthma medications to make sure you aren't already taking an inhaled steroid. Finally, it should go without saying, but don't share your nasal spray with anyone else. That is an excellent way to spread infections around.

Nasal steroids like triamcinolone do not work quickly. It might take up to a week for them to kick in. After that, you will use them for a few weeks during your allergy season. However, if you are into your second week of trying a nasal steroid and are experiencing no relief, talk to your pharmacist. Nasal steroids might not be the medication for you. If you find you need your nasal steroid for 6 months continuously, talk to your doctor or pharmacist. It is not that you can't use a nasal steroid that long, but it is probably a good idea for the doctor to check you out to make sure the problem really is just allergic rhinitis.

Besides my Kindergarten teacher, one of my favourite misnamings was after a job interview. I drove out from U of M in Winnipeg to a very pretty little City in Western Manitoba, just north of a National Park. This City was known for its Ukrainian heritage. I had a good interview and afterwards the pharmacy owner introduced me to some of his staff. He introduced me as Kevin Shewchuk. I took that as a good sign. I was still being misnamed as Kevin, but after only an hour in this City, my name was already being Ukrainianized. I figured the people of this small City must already be starting to like me.

As always if you have any questions or concerns about these or other products, ask your pharmacist.

We now have this and most other articles published in the Parkland Shopper on our Website. Please visit us at www.dcp.ca

The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional.

 


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