"SPRING HAS SPRUNG... the grass is "riz"  I wonder where my Kleenex is!" 

Sorry for the questionable poetry, but with the spring weather, plants are starting to bloom, and soon pollen will be in the air.
ALLERGIES and ANTIHISTAMINES are very relevant to a lot of people, especially during the growing season.
ALLERGIC RHINITIS, often called "hay fever",  literally means "allergic nose inflammation".  Allergic rhinitis can be seasonal or year-round. An allergen (which is something that triggers an allergy) in most cases will cause the triggering of allergic symptoms at about the same time each year. Spring attacks are usually due to tree pollens, whereas grass pollens dominate the summer, and weed pollens are prevalent in the fall. Allergic rhinitis affects about 20% of Canadians.
When a person with Allergic rhinitis is exposed to an allergen, the body responds by releasing histamine. Histamine causes fluid to escape from capillaries into tissues which leads to the classic symptoms of an allergic reaction: runny nose, itching, sneezing and watery eyes.
Since histamine release causes the classic allergic symptoms, it is logical that ANTIHISTAMINES are useful to relieve or prevent these symptoms. Antihistamines prevent histamine from attaching to your cells and causing the runny nose, itching, sneezing or watery eyes.
The older antihistamines (First generation antihistamines) like brompheniramine (was in Dimetapp), chlorpheniramine (eg.Chlortripolon), and diphenhydramine (Benadryl) were effective (and still are effective) to treat these allergic symptoms but these antihistamines also work in the brain and cause drowsiness as a side effect.
The newer antihistamines (Second generation antihistamines) such as cetirizine (Reactine), loratadine (Claritin), or desloratadine (Aerius) generally are longer lasting and since they do not enter the brain, they are effective without causing drowsiness. 
Antihistamines are very beneficial, but can cause side-effects such as drowsiness as discussed, should not be mixed with alcohol, and are not safe for everybody
Patients with liver or kidney problems should not take antihistamines without consulting their doctor.  
The safety of using antihistamines during pregnancy or breastfeeding is discussed in an excellent article, "Safety of antihistamines during pregnancy and lactation", in Canadian Family Physician. Generally speaking the older antihistamines seem to be safe during pregnancy, but there is less data regarding the newer Second generation antihistamines. A lack of studies in pregnancy tells us to be careful and to always take as few medications as possible during any pregnancy. Check with your doctor or pharmacist if you are pregnant or breastfeeding. Other resources regarding drugs and pregnancy are "www.motherisk.org" as well as www.safefetus.com. Most pharmacies have a well respected text, Drugs in Pregnancy and Lactation, by Briggs.
Talk to your doctor before using a first generation antihistamine if you have any of the following health issues:
- Glaucoma
- Trouble urinating (because of an enlarged prostate)
- Breathing problems such as asthma, emphysema or chronic bronchitis
- Thyroid disease
- Heart disease
OTHER TREATMENTS for allergies include:
- antihistaminic eyedrops (some are available without a prescription, some need a prescription)
- a corticosteroid nasal spray (eg. budesonide, flunisolide, fluticasone, mometasone, and others) which require a prescription.
- an anticholinergic nasal spray (eg. Ipratropium) which needs a prescription.
- prednisone tablets for serious allergic reactions which also needs a prescription.
- injectable epinephrine (such as Epi-Pen) which is used for emergencies (see your doctor).
- "allergy shots" or desensitization (allergen immunotherapy) may be an option (see your doctor)
- sometimes people are able to AVOID THE ALLERGEN by various methods such as using air conditioning, keeping windows closed during pollen season, keeping your home as clean as possible to avoid dust mites, and trying to keep your home free from mould by eliminating dark and damp areas.
For more information about various diseases (allergic rhinitis included) as well as many medications such as antihistamines, be sure to check out our "Useful Links". Some of the above information in this newsletter may also be found at:

If you have questions, please check with your doctor or ASK YOUR PHARMACIST. Happy spring cleaning everyone!

Philip A. Smith, B.Sc.Phm.