If you have asthma, there's a good chance that an underlying
allergy—whether it's to dust mites, pollen, cockroaches, or cat
dander—is playing a key role in your breathing problems. (About
60% to 90% of people with asthma have allergic asthma.)
The
first step is to avoid the allergen, but that's not always possible
or sufficient to stop symptoms, like coughing, wheezing, and
shortness of breath.
That's where medication comes in. Here
are some common drugs used to treat allergic asthma.
Inhaled corticosteroids are one of the most important therapies
for any asthma, including allergic asthma.
"These are the
gold standard and they work by basically blocking the inflammation
response in the lungs," says Mitchell H. Grayson, MD, associate
professor of pediatrics, medicine, microbiology, and molecular
genetics at the Medical College of Wisconsin in Milwaukee.
Known
as "controller" medications, they take a few days to
work—so they aren't for short-term symptom control. (Here are
some inhaled
corticosteroids drug names and potential side effects.)
These drugs, like Singulair
(montelukast sodium), can treat allergic asthma because they
inhibit an inflammation-causing chemical released by the immune
system. However, they can also treat non-allergic asthma too, says
Jill Poole, MD, associate professor of internal medicine at the
University of Nebraska Medical Center in Omaha.
The pros are
that they come in pill form and they have few side effects. The
drawback is that the effect is generally mild. "If you have mild
persistent or mild intermittent asthma, sometimes they will work
quite well," Dr. Mitchell says.
You know these inhalers—every asthmatic in the movies
carries one to take an occasional puff. Known as "rescue
medications," these drugs act within minutes to quickly resolve
symptoms.
"We warn everyone who has asthma to carry one
of these," says Dr. Poole.
Albuterol and related
medications such as Maxair (pirbuterol) are bronchodilators, meaning
they work by relaxing the airways. These drugs shouldn't be used
frequently (1-2 times a week or less). People with exercise-induced
asthma can use one 20 minutes before working out to prevent problems,
Dr. Mitchell says.
People who find themselves using rescue medications on a frequent
basis may need to switch to long-acting
beta agonists, which can be effective for 12 hours or more, says
Dr. Poole.
Common products include Advair (a combination of
the beta agonist fluticasone and the steroid salmeterol) and
Symbicort (a combination of the beta agonist formoterol and the
steroid budesonide). A combination formulation (a beta agonist plus a
steroid) is important as long-acting beta agonists on their own can
worsen asthma.
Antihistamines block the immune system chemical histamine, which
is key in allergic reactions.
"If you have an allergy
component to your asthma, they can be beneficial," says Dr.
Poole. Antihistamines are usually combined with inhaled
corticosteroids or Singulair and can reduce inflammation in both the
nose and the lungs. They are cheap, available over-the-counter, and
have relatively few side effects. They're quick acting so may help if
you're allergic to cats and are about to visit a friend with one,
says Dr. Grayson. Antihistamines shouldn't be used chronically.
Xolair is one of the few drugs specifically for allergic asthma.
It binds to immunoglobulin E (IgE), an antibody type produced in
response to an allergen.
It won't help non-allergic asthma, a
type triggered by exercise, cold air, or other non-allergy irritants.
(About 10% to 40% of all asthma cases are non-allergic).
Xolair
is expensive so it is usually given in more severe cases, says Dr.
Mitchell, such as people who have repeat trips to the emergency room.
It's an injected drug and has a boxed warning about a risk of
anaphylaxis, a potentially life-threatening allergic reaction.
(Doctors monitor for such reactions after giving the injections.)
Allergy shots, or "immunotherapy" can be helpful in mild-to-moderate allergic asthma. The first step is to get a skin test to identify your allergens. Then you get a shot containing a small amount of the allergen (say, cat dander) about once a week. Four to six months later, you begin maintenance shots once every three-to-four weeks. Eventually, your body becomes desensitized to the substance, but this can take up to five years, says Dr. Poole. And it's not clear how effective the shots are for anything other than hayfever, adds Dr. Grayson.
Oral corticosteroids, as opposed to inhaled steroids, are
generally used in the short term for serious asthma attacks, says Dr.
Mitchell. This stronger form of the drugs can cause potentially
serious side effects if used in the long term.
If you still
have symptoms and a controller medication isn't doing enough to stop
them, your doctor might want to give you oral steroids for four to
five days to get you back into good health. Oral steroids, such as
prednisone take 4-6 hours to take effect, Dr. Mitchell says.
Theophylline, sold under brand names such as Theo-24 and Uniphyl,
is also a bronchodilator and has been used for relief of symptoms,
particularly coughing at night.
It comes in pill form, which
is a plus. But there are potential side effects ranging from diarrhea
to neurological problems if the dose gets too high.
Patients
have to have regular blood tests and the drug is "hardly used
any more," says Dr. Poole.
Pets can be your best friends, but if you have allergies or asthma, they can also be your worst enemy. Pets shed dander, a combination of dead skin cells and hair (or feathers), which can trigger asthma attacks and allergic reactions in some people. However, you can cut down on pet allergens at home.