Antihistamines reduce allergy symptoms but have side effects
By Landis Lum
Q. My son and wife have terrible hay fever. What can be done?
A. I paid a visit to the drugstore to see what was on hand, and I can tell you what I wouldn't do — I wouldn't use any Benadryl products for a young student who has school the next day.
Benadryl's active ingredient, diphenhydramine, worsened learning when given to school children with hay fever. Diphenhydramine is in Nytol and Sominex for sleep!
Even chlorpheniramine (Chlortrimeton), when given at bedtime, causes lingering adverse effects the next day. And in the elderly, these drugs increase the risk of falls, constipation, confusion and urinary retention.
Similar antihistamines to avoid are clemastine, brompheniramine (Dimetane), triprolidine, cyproheptadine and hydroxyzine.
Instead, I'd use nonsedating, second-generation antihistamines such as loratadine (Claritin, Alavert), fexofenadine (Allegra) and desloratadine (Clarinex), which cause fewer problems with coordination, driving ability and mental alertness. Allegra is especially good at not causing drowsiness, is available by prescription and can be used in patients as young as 6. Loratadine and the mildly sedating but stronger Zyrtec are available as syrups and can be used in children as young as 2.
If the above don't do the trick for itchy, runny nose and eyes and sneezing, then ask your doctor about steroid nasal-inhaler sprays, which work better than antihistamines — and without the mental clouding. While antihistamine pills lead to a 25 to 35 percent decrease in symptoms in up to 60 percent of patients, nasal steroids result in a 60 to 70 percent symptom reduction in more than 80 percent of patients. However, antihistamines do reduce itching better.
Nasal steroids are safe. A six-year study showed no changes in blood steroid levels or in biopsies (tissue samples) of the nasal mucous membrane after nasal steroid use. And nasal steroids don't seem to lead to cataracts, osteoporosis or glaucoma.
However, in children, studies show nasal steroids such as budesonide and beclomethasone can slow growth, while agents such as Nasonex don't, probably because of reduced absorption of the latter into the blood stream.
Therefore, if nasal steroids are used before puberty, then drugs with low absorption such as Nasonex or Flonase are recommended. Weaker but without dangerous side effects is the nonsteroid cromolyn.
Nasal steroids take 12 to 96 hours to start to work and two months for full effectiveness, while you can inhale a couple puffs of cromolyn an hour before visiting the home of your cat- and flower-loving friend to reduce sneezing. Of course, the best treatment is to avoid exposure to what you're allergic to. To reduce dust mites, for instance, keep relative humidity to less than 45 percent, and use dehumidifiers, not humidifiers.
For additional information on related topics, see www.medlineplus.gov.
Dr. Landis Lum is a family-practice physician for Kaiser Permanente and an associate clinical professor at the University of Hawai'i's John A. Burns School of Medicine.
Send your questions to Prescriptions, Island Life, The Advertiser, P.O. Box 3110, Honolulu, HI 96802; fax 535-8170; or e-mail islandlife@honoluluadvertiser.com.
This column is not intended to provide medical advice.
