Pharmacologic Choices for Allergies

Symptoms of allergic rhinitis symptoms affect 20% of the population.  In addition to nasal symptoms, there are also eye redness, tearing, and cough.  Some  patients complain of fatigue, lethargy, headache, impaired concentration, and difficulty in learning.  First-generation antihistamines are Brompheniramine (in Bromfed, Dimetapp), Chlorpheniramine  (in Chlor-Trimeton, Sinutab and some formulations of Triaminic) and Diphenhydramine (in Benadryl).  Two problem with these are that they lack selectivity for the body’s H1 receptors and they cross the blood-brain barrier.  As such, they can cause sedation and drowsiness as well as impair alertness and cognition which may affect academic performance. 

Second-generation antihistamines are more selective for H1 receptors and do not as readily cross the blood-brain barrier.  Loratadine (in Claritin) and Fexofenadine (in Allegra) are non-sedating.  These and other 2nd generation antihistamines, such as Cetrizine (in Zyrtec) and Azelastine (a nasal spray) are less likely than 1st generation ones to cause dry mouth and constipation.  Many preparations of 1st and 2nd generation antihistamines are mixed with a decongestant, usually pseudoephedrine.

Excepting for associated eye symptoms of allergic rhinitis, intranasal corticosteroids are the most effective agents for allergic rhinitis (e.g., Beconase, Flonase, Nasacort, Nasalide, Nasonex, Rhinocort, Vancenase).  Parents need to understand that these are non-anabolic steroids and are prescribed tiny doses (“in microgram and not in milligram quantities”).  Local bleeding, irritation, scabbing and burning are the most common adverse effects.  Cromolyn nasal spray (now available over-the-counter) is very safe, but not as effective as intranasal corticosteroids.  Its recommended dose is four-times per day, but twice daily and a dose before exposure to an airborne allergen are two methods that many patients and doctors have found to be effective. 

(Prenner BM:  J Resp Diseases for Pediatr 2002; 4(4):154-160.)

Comment:  Brand names (in italics) were not in the original article and are not complete lists, but were added here for reader familiarity.  Many antihistamines (both 1st and 2nd generation) do not seem to be effective for many or have only minimal benefit.  Unfortunately my favorite, Triprolidine (in Actifed), was not mentioned in the article. – H.T.