Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: MONDAY, March 26, 1990 TAG: 9003242374
SECTION: EXTRA PAGE: E1 EDITION: METRO
SOURCE: Jane E. Brody
DATELINE: LENGTH: Long
When the runny nose and itchy eyes become sufficiently annoying, most will reach for one of the dozens of over-the-counter or prescription drugs that promise relief from allergy symptoms.
But which drug should you take or give to your allergic child? Some medications once available only by prescription are now sold over the counter.
The consumer, perhaps in consultation with a pharmacist but without the guidance of a physician, may now have to select an appropriate treatment and to learn how to use it properly.
To add to the confusion, the choices of treatments, both prescription and non-prescription therapies, have multiplied greatly in recent years.
Many of the newer medications are no more effective than the old standbys but are much less likely to produce unpleasant and possibly hazardous side effects.
But the new drugs are also a lot more expensive, especially for those whose symptoms begin with release of tree and grass pollen in March and don't end until the ragweed dies with the first fall frost.
Antihistamine
\ s For most people with life-disrupting allergies, antihistamines have long offered relief.
Antihistamines are drugs that prevent allergy symptoms by blocking the action of histamine, the natural body substance released in response to substances that trigger an allergic reaction.
Histamine, in turn, musters the release of a cascade of irritating body chemicals that directly cause the symptoms of allergy.
Antihistamines have been around for a long time and drugs like Benadryl (diphenhydramine) and Chlor-Trimeton (chlorpheniramine maleate), which are sold over the counter, are all too familiar to middle-aged adults with allergies.
Though these drugs can be highly effective against allergic symptoms, they also have other actions that may result in a number of unwanted effects.
They can produce excessive dryness of the mouth and other mucus-secreting tissues and result in difficulty breathing and urinating.
But most important, the old antihistamines readily enter the brain, producing drowsiness in most people and excitation in some, especially small children.
Either way, the drugs can interfere with school performance. Reaction time, judgment and coordination may all be impaired, which can make it unsafe to operate a motor vehicle or other machinery.
Although all such medications warn of these risks on the package label, a 1989 Gallup poll revealed that 61 percent of people who take the drugs ignore the warning and drive while under the influence of the medication.
Studies have shown that impairment persists for several hours after taking the medication, but people are unaware that they are not functioning normally. Thus, sedating antihistamines are best taken only at bedtime.
The new generation of antihistamines, led by Seldane (terfenadine), now the most frequently prescribed antihistamine, is free of brain effects because the drugs do not enter the brain. Competing with Seldane is Hismanal (astemizole), and several other related nonsedating antihistamines are in final stages of testing and may soon be marketed here.
According to Dr. Philip Norman, a leading allergist at The Johns Hopkins University School of Medicine, the new drugs are at least as effective in squelching allergy symptoms as the old ones, and the new drugs have an "excellent safety record."
Still, he said in an interview, "No antihistamine works for everyone. Different drugs are more or less effective in different people and they produce different side effects."
Thus, finding the right antihistamine for you may require some trial-and-error testing. And unless your drug prsecriptions are covered by insurance, you may have to consider economics in your choice, since all the nonsedating antihistamines are twice as expensive as the old ones.
Dr. Michael Sly, pediatric allergist at the Children's National Medical Center in Washington, D.C., noted too that the nonsedating antihistamines are effective and safe for use in children.
However, since they are available only in tablet form, children under 6 may be unable to swallow them.
Intranasal medications\ "Antihistamines are not the whole answer to seasonal allergies," Dr. Norman said. At least two types of medications that are administered through the nose have proved helpful and safe: steroids and cromolyn sodium.
Steroids can be applied into the nose through a freon-propelled aerosol or a pump-activated water-based spray.
When used locally, the drugs have few if any side effects and little risk of a steroid overdose, even when used steadily for weeks at a time.
However, the steroids slowly reduce swelling of tissues and it may take a day or two to experience the benefits of intranasal steroids.
Cromolyn sodium (marketed as Nasalcrom) also has a delayed effect because its action is preventive, not curative. It also has an excellent safety record, and can be used as often as five times a day without untoward effects. An inhaled form of cromolyn has revolutionized the treatment of asthma by blocking the effects of allergic triggers.
According to Norman, in some patients intranasal cromolyn may have to be used in conjunction with antihistamines or decongestants to control allergy symptoms.
Decongestants\ These are marketed separately (for example, Sudafed or pseudoephedrine) or in combination with antihistamines (Actifed, Sinutab, Drixoral, Dimetapp and Sudafed Plus, among others).
Most decongestants are stimulants, and many people incorrectly assume that when taking a combination drug, the stimulating effect of the decongestant will counteract the sedation produced by the antihistamine.
However, tests have shown that even if a person taking antihistamines is wide awake, mental and physical performancemay be impaired.
Dr. Douglas Johnstone, pediatric allergist at the University of Rochester School of Medicine and Dentistry, noted that some people experience a rebound reaction from too frequent use of decongestants, similar to the rebound experienced when ordinary nasal sprays are overused.
Rather than relieving upper respiratory congestion, overuse of the drug can make it worse and lead to dependence upon evermore frequent use of the medication.
Because of their stimulating properties, decongestants can cause sleeplessness, nervousness, hyperactivity and depressed appetite.
The drugs can also raise blood pressure and are not recommended for people being treated for high blood pressure.
They may also cause excessive dryness of the mouth and other mucus-secreting tissues.
by CNB