Asthma in Women, Asthma in Pregnancy (cont.)
The safest and most effective asthma treatment is inhaled medication,
including corticosteroids
Salmeterol is a relatively new medication that is a longer-acting b-agonist.
It is often used in people frequently needing b-agonists, in hopes of decreasing
the need for short-acting rescue medications. It is also sometimes added to
inhaled corticosteroids to improve asthma control or to reduce the dosage of
these inhaled corticosteroids needed for asthma control. Some research has shown
that asthma control in people already using steroid MDI's is improved moreso
by addition of salmeterol than by raising the dose of the steroid MDI. Of
course, this means using two inhalers instead of one inhaler. Salmeterol is
sometimes used as a long-term medication to prevent exercise-induced asthma, but
there is some research showing that its effectiveness when used for this
specific reason may slightly decrease gradually with time.
Cromolyn is a medication that has been around for a long time. It is one of
the safest medications of all available prescription medications, but it is not
very potent. It is used sometimes as maintenance therapy to prevent acute asthma
attacks, but it does not help during an acute attack.
C. Maintenance Therapy: Oral (by mouth) for Long-Term
Control
Theophylline is an older asthma medication that is taken in pill-form. It
acts as a bronchodilator and seems to be especially helpful for people with
night-time decrease in lung function that commonly occurs in people with asthma.
It's use at night has largely been replace by the long- acting bronchodilator
salmeterol.
Use of theophylline requires blood
tests to determine blood levels of the medication as part of its safety
monitoring. It also has potential side effects, including nausea, increased
heart rate (experienced as palpitations),
irritability, and insomnia, among others. These side effects are similar to
those of caffeine. It also has potential for
many drug interactions, meaning it can affect the use of other medicines used at
the same time for other conditions, and vice-versa. Acute illnesses can also
alter its metabolism (how
the drug acts in the body and is eliminated from the body). For these reasons it
is infrequently used in asthma treatment. Newer medications particularly
inhalers like salmeterol are more effective and have less side effects.
A new class of maintenance medicines has emerged in the last several years.
In fact, they were the first new treatment to be approved in 20 years for
chronic asthma They are pills that act to reduce the production of, or the
action of, chemicals that the body itself makes during an asthma attack. These
chemicals called leukotrienes are produced by the inflamed airway, and narrow
the airways. These medications are called anti-leukotrienes. Depending on the
medication, they either stop the production of the trouble-making leukotrienes,
or else block the harmful action of the leukotrienes. It is hoped that they can
reduce the need for, or possibly the dose of, other asthma medications. These
medications include zafirlukast, montelukast, and zileuton. These
antileukotriene drugs directly block bronchoconstriction but are also
anti-inflammatory, whereas corticosteroids are only anti-inflammatory. These
medications have not been compared to each other, so it is not known if one has
any clear advantage over the others. Most of the benefit of these drugs is seen
within 2-4 weeks of starting the medication (A), and they generally reduce the
need for rescue therapy by 1/3rd (A). They help decrease nighttime asthma
symptoms as well (A).
When
compared head-to-head, the anti-leukotrienes and the inhaled steroids each help
certain lung function tests, quality of life, night-time awakenings,
numbers of asthma-control days, and asthma attacks. The two medications were
each helpful as controller medications for chronic asthma. Both drugs were very
well tolerated in terms of side effects. Other research has added anti-leukotrienes
to high doses of inhaled steroids in chronic asthma patients. Patients who did
have the anti-leukotriene added had a better chance of successfully reducing the
inhaled steroid dose than those who did not add an anti-leukotriene to their
inhaled corticosteroids. The anti-leukotrienes are not yet felt to be useful in
severe asthma, and many people with milder asthma are already controlled and
happy on either intermittent rescue medication or chronic inhaled corticosteroid
MDI's with only occasional need for rescue medication.
It might be that these medications if used regularly for
many weeks, are good at preventing exercise-induced asthma, as is being shown in
recent research, and that they may help a certain type of asthma called
aspirin-sensitive asthma. However, there are many issues that have come up
regarding these medications; people may find using MDI's more convenient that
taking these pills, MDI's in low doses have minimal absorption compared to pills
thus possibly less potential for side effects, and long-term studies of these
pills are not available yet. Also, zileuton has potential to cause abnormal
liver function test in the blood, so that all people taking this medication will
need liver test monitoring via blood tests at intervals, especially in the first
3 months of use. Therefore their precise role is still being determined,
especially in the long-term. Specifically, we need long-term safety and
effectiveness data,
and need to clearly establish what specific group of asthmatics will benefit
most from them. Probably for the time being, in real daily practice while we
await research, their use is considered in the following mild to moderate
asthmatics: those with less than optimal benefit from inhaled steroid, those
with aspirin-sensitive asthma, and those needing high doses of inhaled or oral
steroids.