Reprint, Aynor Journal (South Carolina) v9 #22, ed. Kathy Dix
20 March 1997 |1
(069) Allergy Update and Lessons Learned. By Dr. Mark E. Meijer
The body does many things without the aid of human thought. Breathing and regulating
blood pressure are two examples of functions that require no thought (that is, until illness
strikes).
When a patient develops high blood pressure (hypertension) or shortness of breath, then
some mental effort is needed to regulate these functions. Patients have to remember to take their
medicines. The immune system is probably one of the most complicated systems in the body.
Every substance outside the body must be sorted out as “friend or foe.” Bacteria are supposed to
be attacked and destroyed. Vitamins are supposed to be absorbed and used. Mistakes can be
fatal. This complicated immune system is poorly understood. Your thoughts are not the controls
that decide these difficult immune decisions.
Many commands used by the immune system in your body are transmitted by chemicals
that are released in the blood circulation. As each of these chemicals is identified by scientists,
they are given a name.
Allergic symptoms of sneezing, itchy eyes, itchy nose, itchy welts, and/or asthma are at
least partially triggered by the chemical signal called histamines. The immune system
mistakenly identifies harmless substances (e.g., pollen, cat dander, mold, etc.) the body
should attack. The immune system signals this attack with histamine release.
Drugs called “antihistamines” try to stop the histamine signal by blocking the
message. Antihistamines are one treatment option for allergy sufferers. Most
antihistamines are old drugs. Many forms or varieties of antihistamines have been
invented over the years. All the older antihistamines share the same unfortunate side
effect of drowsiness. For many allergy sufferers, the drowsiness of treatment
(antihistamines) was as bad or worse than the disease itself (allergies). Therefore, antihistamines
were not a practical option for some patients.
The first non-sedating antihistamine was a prescription medicine called Seldane
(terfenadine). For years, it was the Number One prescribed antihistamine because it was
effective and did not cause drowsiness. As with many new and improved drugs, over the years
new problems are discovered. While serious drug interaction between Seldane and other drugs
were rare, with time it was discovered that some of these interactions were fatal. Rare drug
interactions can only be discovered if the reaction is unusually severe. Sudden death or nearfatal arrhythmias in otherwise young, healthy people was definitely an unusual side effect.
Seldane is perfectly safe when properly used. Unfortunately, some of the “need to avoid” drug
interactions are common (e.g., the antibiotic erythromycin). Accidently mixing Seldane and
erythromycin is a present and current problem.
Fortunately since then, several more new, non-sedating antihistamines have been
discovered without this problem.
Update Number One: The FDA (Food and Drug Administration) is considering pulling
Seldane off the market because of its rare, fatal drug interaction. Seldane can easily be replaced
by an almost identical new drug call Allegra (fexofenadine). Satisfied Seldane users who want
to use the same drug as Seldane should consider switching to the very similar Allegra.
Update Number Two: For years drug manufacturers have labeled antihistamine products
with the warning that asthmatics and hypertensive patients should not take antihistamines.
Only rarely will blood pressure rise to alarming heights while on an antihistamine.
Hypertensive patients, when taking antihistamines, should take the additional precautions of
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Allergy Updates
Reprint, Aynor Journal (South Carolina) v9 #22, ed. Kathy Dix
20 March 1997 |2
checking their blood pressure. Most patients will find their blood pressure will do okay while on
these medications.
Antihistamines were supposed to be bad for asthmatics because it makes mucus
secretions thicker. There is no real proof that this myth is a problem.
Asthmatics wheeze because they have an allergic inflammation (swelling) of the lungs.
Antihistamines help block histamine induced inflammation. To the degree an asthmatic wheezes
because of histamine release, antihistamines will help.
Update Number Three: Other immune chemicals (command signals) are being discovered
that cause allergic inflammation. Scientists are creating new drugs to block these newly
discovered chemicals.
For example, the new kid on the block in asthma is called leukotrienes. Leukotriene
inhibitors are now being manufactured. The new stuff just released (and approved by the FDA)
is called “Zileuton.”
Remember, Seldane was once the new kid on the block, too. Allergy patients died before
problems were worked out with this new drug.
Most asthmatic patients who are doing well should sit tight and watch to see how
Zileuton works out. Hopefully, scientists won’t discover any new problems down the road.
Only asthmatic sufferers who are doing poorly should consider these new treatment options with
their doctor.
Many prescription drug manufacturers now promote new products by advertising directly
to the patient, trying to bypass doctors and influence patients’ choices in medications. Time and
experience is needed to truly see that these new drugs are safe.
In summary, allergies are an old and complicated problem. New solutions are being
discovered every day. But “Buyer Beware!” FDA approval is no guarantee that new
medications are better or safer. Some lessons are still learned the hard way.
Old myths are hard to die and new legends are hard to build. Allergy sufferers need to
keep in touch with their doctor. Look out for Update Number Four, Number Five … and on and
on. © All Rights Reserved by Mark Erik Meijer, MD
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