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The general information FAQ is also available in html format on the World Wide Web, at
<URL: http://www.cco.caltech.edu/~wrean/asthma-gen.html>.
Posted 12/95
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From: wrean@cco.caltech.edu (Patricia Rose Wrean)
Newsgroups: alt.support.asthma,alt.med.allergy,sci.med,alt.answers,sci.answers,news.answers
Subject: alt.support.asthma FAQ: Asthma -- General Information
Followup-To: alt.support.asthma,alt.med.allergy,sci.med
Date: 17 Nov 1995 23:30:14 GMT
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Summary: This posting contains a list of frequently asked
questions and answers about asthma, including its
symptoms, causes, and forms of treatment. It should
be of interest to anyone who has asthma or knows
someone who does.
Keywords: asthma allergy faq general information Xref: senator-bedfellow.mit.edu alt.support.asthma:9211 alt.med.allergy:6596 sci.med:152596 alt.answers:13586 sci.answers:3446 news.answers:57856
Archive-name: medicine/asthma/general-info
URL: http://www.cco.caltech.edu/~wrean/asthma-gen.html
Posting-Frequency: monthly
Last-modified: 17 November 1995
Version: 4.5
alt.support.asthma FAQ: Asthma -- General Information
Introduction:
Welcome to alt.support.asthma! This newsgroup provides a forum for the discussion of asthma, its symptoms, causes, and forms of treatment. Please note that postings to alt.support.asthma are intended to be for discussion purposes only and are in no way to be construed as medical advice. Asthma is a serious medical condition requiring direct supervision by a physician.
This FAQ attempts to answer the most frequently asked questions about asthma on the newsgroup alt.support.asthma. It is maintained by Patricia Wrean <wrean@caltech.edu>. The Asthma Medications FAQ is also posted monthly as a companion to this one. For information about allergies, please see the alt.support.asthma FAQ: Allergies -- General Information (still under construction), and its companion posting, the Allergy Medications FAQ.
Please be aware that the information in this FAQ is intended for educational purposes only and should not be used as a substitute for consulting with a doctor. Most of the contributors are not health care professionals; this FAQ is a collection of personal experiences, suggestions, and practical information. Please remember when reading this that every asthmatic responds differently; what is true for some asthmatics may or may not be true for you. Although every effort is made to keep this information accurate, this FAQ should not be used as an authoritative reference.
Comments, additions, and corrections are requested; if you do not wish your name to be included in the contributors list, please state that explicitly when contributing. I will accept additions upon my own judgement -- I'll warn you right now that I'm a confirmed skeptic and am not a great believer in alternative medicine. All unattributed portions are my own contributions. For more information about asthma medications, there is also an Asthma Medications FAQ that is posted as a companion to this one.
+ = added since last version
& = updated/corrected since last version
General Information:
1.0 What is asthma?
1.0.1 What is chronic asthmatic bronchitis?
1.0.2 What is status asthmaticus?
1.0.3 What is anaphylactic shock?
1.0.4 What is COPD?
1.0.5 What is emphysema?
1.0.6 What is bronchitis?
& 1.0.7 What is pneumonia?
1.0.8 What is cystic fibrosis?
1.1 What is an asthma attack?
1.1.1 What is wheezing?
1.1.2 Do all asthmatics wheeze?
1.1.3 What is "coughing asthma"?
1.1.4 Is asthma hereditary?
& 1.2 How is asthma diagnosed?
1.2.1 What is a spirometer?
1.2.2 What is a peak flow meter?
& 1.3 How is asthma normally treated?
1.3.1 How is an acute asthma attack treated?
& 1.4 What are the most common triggers of asthma?
& 1.4.1 What is intrinsic/extrinsic asthma?
1.4.2 Can gastric reflux trigger asthma?
Medications:
& 2.0 What are the major classes of asthma medications?
2.1 What are the names of the various asthma medications?
2.1.1 Are salbutamol and albuterol the same drug?
2.1.2 Can albuterol be taken while taking salmeterol?
2.2 Are some asthma drugs banned in athletic competitions?
2.3 What kinds of inhalers are there?
2.3.1 Do inhaler propellants bother some asthmatics?
& 2.3.2 What is a spacer? What is a holding chamber?
2.3.3 What is "thrush mouth" and how can I avoid it?
2.3.4 Is Fisons still making the Intal Spinhaler?
2.3.5 What's the difference between Spinhalers and Rotahalers?
2.3.6 Why are so many asthma drugs taken via inhaler?
& 2.3.7 How can I tell when my MDI is empty?
2.4 What kinds of tablets are there?
2.4.1 Why do I need a blood test when taking theophylline?
2.4.2 Why are combination pills not commonly prescribed?
2.5 What is a nebulizer?
2.6 What medications should asthmatics be careful about taking?
Miscellaneous:
& 3.0 What resources are there for asthmatics?
& 3.1 Where can I get the latest copy of the FAQs?
3.2 What is an FAQ, anyway? What is a Usenet newsgroup?
List of Contributors
References
Disclaimer
Asthma is best described by its technical name: Reversible
Obstructive Airway Disease (ROAD). In other words, asthma
is a condition in which the airways of the lungs become
either narrowed or completely blocked, impeding normal
breathing. However, in asthma, this obstruction of the lungs
is reversible, either spontaneously or with medication.
Quickly reviewing the structure of the lung: air reaches the
lung by passing through the windpipe (trachea), which divides
into two large tubes (bronchi), one for each lung. Each
bronchi further divides into many little tubes (bronchioles),
which eventually lead to tiny air sacs (alveoli), in which
oxygen from the air is transferred to the bloodstream, and
carbon dioxide from the bloodstream is transferred to the air.
Asthma involves only the airways (bronchi and bronchioles),
and not the air sacs. The airways are cleaned by trapping
stray particles in a thin layer of mucus which covers the surface
of the airways. This mucus is produced by glands inside the
lung, and is constantly being renewed. The mucus is then
either coughed up or swept up to the windpipe (trachea) by
cilia, tiny hairs on the lining of the airways. Once the
mucus reaches the throat, it can again be coughed up or,
alternatively, swallowed.
Although everyone's airways have the potential for constricting
in response to allergens or irritants, the asthmatic's airways
are oversensitive, or hyperreactive. In response to stimuli,
the airways may become obstructed by one of the following:
- constriction of the muscles surrounding the airway;
- inflammation and swelling of the airway; or
- increased mucus production which clogs the airway.
Once the airways have become obstructed, it takes more effort
to force air through them, so that breathing becomes laboured.
This forcing of air through constricted airways can make a
whistling or rattling sound, called wheezing. Irritation of
the airways by excessive mucus may also provoke coughing.
Because exhaling through the obstructed airways is difficult,
too much stale air remains in the lungs after each breath.
This decreases the amount of fresh air which can be taken in
with each new breath, and this lack of fresh air means that
less oxygen is available for the whole body. This decreased
supply of oxygen is what makes an uncontrolled asthma attack
so serious.
Chronic asthmatic bronchitis is the condition in which the
airways in the lungs are obstructed due to both persistent
asthma and chronic bronchitis (see sections 1.0 and 1.0.6).
People with this disease generally also have a persistent
cough which brings up mucus. Chronic asthmatic bronchitis
which also involves emphysema is usually classified under
the more general category of COPD.
Status asthmaticus is defined as a severe asthma attack that
fails to respond to routine treatment, such as inhaled
bronchodilators, injected epinephrine (adrenalin), or
intravenous theophylline.
Anaphylactic shock is defined as a severe and potentially
life-threatening allergic reaction throughout the entire
body. It occurs when an allergen, instead of provoking a
localized reaction, enters the bloodstream and circulates
through the entire body, causing a systemic reaction.
(There may also be an intrinsic trigger, as some cases of
exercise-induced anaphylaxis have been reported.)
The symptoms of anaphylactic shock begin with a rapid
heartrate, flushing, swelling of the throat, nausea, coughing,
and chest tightness. Severe wheezing (asthma), cramping, and
a rapid drop in blood pressure follow, which may lead to cardiac
arrest. Hives and vomiting are also common features. The
treatment for anaphylaxis is intravenous epinephrine (adrenalin),
with antihistamines and steroids also being used in selected
cases. Aminophylline may also be given for pronounced asthmatic
reactions that do not respond to epinephrine.
COPD is chronic obstructive pulmonary disease, also known as
either COAD, for chronic obstructive airway disease, or COLD,
for chronic obstructive lung disease. COPD is a disease in
which the airways are obstructed due to a combination of
asthma, emphysema, and chronic bronchitis. The 1987 Merck
Manual notes that "the term COPD was introduced because these
conditions often coexist, and it may be difficult in an
individual case to decide which is the major one producing
the obstruction."
[Maintainer's note: the entries for COPD, emphysema, bronchitis,
pneumonia, and cystic fibrosis have been included because of
common confusion between the various diseases which can affect
the lungs.]
Emphysema is the disease in which the air sacs themselves, rather
than the airways, are either damaged or destroyed. This is an
irreversible condition, leading to poor exchange of oxygen and
carbon dioxide between the air in the lungs and the bloodstream.
Bronchitis is an inflammation of the bronchi, the large airways
inside the lungs. (Bronchiolitis is the inflammation of the
bronchioles, the small airways.) This inflammation often leads
to increased mucus production in the airways.
Bronchitis is generally caused either by a virus or by exposure
to irritants such as dust, fumes, or cigarette smoke. If caused
by a virus, the bronchitis will likely be only temporary. In
the case of prolonged exposure to irritants, particularly
cigarette smoking, if there is permanent damage to the bronchi,
bronchitis may become chronic.
Pneumonia is an infection of the lung tissue. In adults, it is
generally caused by bacterial infections, though viruses, fungi,
and protozoa may also be culprits. The latter microorganisms
have become very common as causes of pneumonia in immunosuppressed
persons, such as those with HIV infection. However, for those
with chronic illnesses, especially cardiac or respiratory
diseases, or those at increased risk for pneumonia, there is a
pneumococcal pneumonia vaccination available as a preventive
measure for the most common of these bacterial infections,
streptococcus pneumoniae. In children, pneumonia is most
commonly caused by viruses.
Cystic fibrosis is a disease in which excessive amounts of
unusually thick mucus are produced throughout the body.
Because this mucus production also occurs in the lungs,
people with cystic fibrosis are extraordinarily prone to
bacterial infections which result in progressive lung damage.
Cystic fibrosis can be diagnosed by a "sweat test" as people
with cystic fibrosis have elevated chloride levels in their
perspiration. This condition often resembles asthma in
children.
An asthma attack, also known as an asthma episode or flare,
is any shortness of breath which interrupts the asthmatic's
well-being and requires either medication or some other form of
intervention for the asthmatic to breathe normally again.
Wheezing is the whistling or rattling sound that occurs when
air flows through obstructed airways. At the start of an
asthma attack, wheezing usually only occurs while exhaling, or
breathing out, but as the attack progresses, wheezing may
then be heard both while inhaling and exhaling. If after
the attack progresses further, the asthmatic then stops wheezing,
this may indicate that many bronchioles (small airways) have
become completely blocked, which is a very serious condition.
No, not all asthmatics wheeze. Although wheezing is extremely
common in asthmatics, in _All About Asthma_, Dr. Paul says,
"It is important to note that not all asthmatic symptoms need be
present for one to experience an asthma attack. For instance,
not all asthmatics wheeze. And sometimes wheezing is so slight,
it can only be heard with a stethoscope. With some asthmatics,
coughing is the only symptom present." Similarly, in _Children
with Asthma_, Dr. Plaut states that children with chronic coughs
"may have asthma even though no wheezing is present." He
diagnoses such children with asthma if their peak flow improves
when given an inhaled bronchodilator.
In _Children with Asthma_, Dr. Plaut defines "coughing asthma"
as "a form of asthma in which coughing is the only symptom and
there is no abnormality in any lung function test." This
condition is also known as "cough variant asthma." Coughing
asthma often improves when standard asthma medications are
taken.
No, asthma itself is not hereditary, but there does seem to be
a hereditary component to the tendency to develop asthma. In
_All About Asthma_, Dr. Paul states that if neither parent has
asthma, the chances of each of their children having asthma are
less than 10%. When one parent has asthma, the chances rise to
25%, and when both parents have asthma, the chances climb to 50%.
(Actually, there is considerable disagreement among my sources
as to the exact numbers, but all agree that the chances climb
dramatically if one or both parents have asthma.)
Similarly, if one or both parents have allergies, the chances
of each of their children having allergies are 35% and 65%,
respectively, compared to a less than 10% chance if neither
parent has allergies.
However, Dr. Paul cautions that "children don't inherit asthma
itself, but the tendency to develop it." Whether or not an
individual develops asthma is also influenced by their exposure
to various other factors such as infections, irritants, and
allergens.
Asthma is diagnosed based on a physical examination, personal
history, and lung function tests. The physical examination looks
for typical asthma symptoms such as wheezing or coughing, and the
personal history provides additional clues such as allergies or a
familial tendency towards asthma. Although lung function tests
have not always been used for diagnosis in the past, the NHLBI
Guidelines for the Diagnosis and Management of Asthma state that
"Pulmonary function studies are essential for diagnosing asthma
and for assessing the severity of asthma in order to make
appropriate therapeutic recommendations. The use of objective
measures of lung function is particularly important because
subjective measures, such as patient symptom reports and
physicians' physical examination findings, often do not correlate
with the variability and severity of airflow obstruction."
Lung function tests may be as simple as measuring peak flow with
a peak flow meter, or using a simple spirometer, or may involve
a battery of spirometry tests in a pulmonary function lab.
A spirometer is a machine for testing lung function that you
breathe in and out of through a hose attached to a mouthpiece.
You are usually given nose clips so that all the air you breathe
goes through the machine. One I've been tested on had a little
expanding tank surrounded by water into which the air goes, and
I could see the top rising and falling as I breathed out and in.
It can measure a fair number of characteristics of your lungs,
including FVC, FEV1, and PEPR. FVC, or forced vital capacity,
is the amount of air that you can exhale forcefully after taking
a deep breath. FEV1, or forced expiratory volume in one second,
is the amount of air that you can be exhale in one second.
Peak flow, or PEPR, is described in section 1.2.2.
The sophisticated spirometers I've seen have a PC attached, and
have neat little curves generated with each breath, which
apparently have characteristic shapes for different respiratory
diseases.
There is a slightly less sophisticated machine that I've blown
into, and I'm not sure if this is also classed as a spirometer or
not, but you take a deep breath and blow into it, much like a
peak flow meter, except that it draws a little graph of how much
volume you've blown out, and I'd imagine that you can get the
FVC and FEV1 off this graph.
For more information, I recommend the book by Drs. Haas,
_The Essential Asthma Book_, which goes into more detail about
the various things you can find out from spirometry.
A peak flow meter is a little plastic device which you blow hard
into, after having taken a deep breath. It records the rate at
which you've blown into it in litres exhaled per minute (L/min)
-- this is called the peak expiratory flow rate (PEF or PEFR).
The meter is essentially a cylinder with a mouthpiece at one end,
a place for the air to escape at the other end, and a calibrated
meter along the side. When you blow into it, a marker is pushed
along the scale and comes to rest at a point which indicates your
PEF. Since you want to measure your maximum peak flow, it is
important to take a deep breath and blow as hard and as fast as
you can. Many asthmatics find that their maximum peak flow provides
a good objective measure of how their asthma is doing, so peak flow
meters now are used extensively for self-monitoring of asthma, and
also for monitoring the effectiveness of asthma medications.
Treatment of mild asthma usually tries to relieve occasional
symptoms as they occur by use of short-acting, inhaled
bronchodilators. Treatment of moderate or severe asthma,
however, attempts to alleviate both the constriction and
inflammation of the airways, through the use of both
bronchodilators and anti-inflammatories. Bronchodilators are
drugs which open up or dilate the constricted airways, while
drugs aimed at reducing inflammation of the airways are called
anti-inflammatories.
For asthma which is strongly triggered by allergies, allergen
avoidance can often greatly reduce the amount of medication
needed to control the asthma. Taking anti-allergic medications
or taking shots for allergy desensitization are other
alternatives. For more information about allergen avoidance
and allergies in general, please see the alt.support.asthma FAQ:
Allergies -- General Information (still under construction).
Taking anti-inflammatory drugs (usually inhaled corticosteroids)
daily for moderate to severe asthma is a relatively new approach
to treating asthma. The idea behind it is that if the underlying
inflammation of the airways is reduced, the bronchi may become
less hyperreactive, making future attacks less likely. Such
anti-inflammatory therapy, however, must be taken regularly in
order to be effective.
An acute asthma attack is usually treated by us of bronchodilators
to reduce the constriction of the airways. Intravenous adrenalin
and theophylline are often given in emergency rooms for this
purpose, if short-acting bronchodilators given by nebulizer
haven't sufficiently controlled the attack.
Once the acute attack is over, anti-inflammatories may be used to
reduce the inflammation of the airways. Inhaled steroids are
usually the first choice, but for a sufficiently severe attack,
oral steroids such as prednisone may also be given.
1.4 What are the most common triggers of asthma?
The most common triggers of asthma are:
- viral respiratory infections, such as influenza (the flu)
or bronchitis;
- bacterial infections, including sinus infections;
- allergic rhinitis;
- irritants, such as pollution, cigarette smoke, perfumes,
dust, or chemicals;
- sudden changes in either temperature or humidity, especially
exposure to cold air;
- allergens, for people with allergies;
- emotional upsets, such as stress; and
- exercise.
Intrinsic and extrinsic asthma are outdated terms which have now
been replaced by terms related to the asthma trigger, since the
inflammatory response of the airways is the same independent of
the cause of the asthma. What was known as extrinsic asthma is
now called allergic asthma, while asthma triggered by non-allergic
factors, formerly called intrinsic asthma, is separated into such
categories as exercise-induced asthma and occupational (chemical-
induced) asthma.
Yes, gastric reflux can act as an irritant which triggers
asthma. Reflux, properly known as gastroesophageal reflux,
occurs when the liquids in the stomach pass up the esophagus,
or feeding tube. Because these liquids are usually highly
acidic, they can irritate and inflame the esophagus, and
also the airways of the lung, should any of this liquid be
aspirated. This irritation can trigger an asthma attack.
Asthma flares caused by reflux are more common at night,
for it is easier for material to pass up the esophagus when
one is lying down. Some simple treatments to prevent reflux
include raising the head of the bed, not eating close to
bedtime, or using either antacids or medications such as
ranitidine (Zantac) which reduce the amount of acid produced
by the stomach.
There are six major classes of asthma medications:
- steroidal anti-inflammatories,
- non-steroidal anti-inflammatories,
- beta-agonists,
- xanthines,
- anticholinergics, and
- anti-allergics.
The first two categories of drug treat the underlying
inflammation of the lung. All steroidal anti-inflammatories
are glucocorticosteroids, which are entirely different from the
anabolic steroids that have become notorious for their abuse
by athletes. There are many different corticosteroids available
for the treatment of asthma, almost all available via inhaler
to reduce the amount of side effects (see section 2.2.6). The
non-steroidal anti-inflammatories currently available are
nedocromil sodium and cromolyn sodium, though cromolyn sodium
is perhaps more properly known as a mast cell stabilizer, since
it blocks both the release of histamine and inflammatory
mediators, which means that although it blocks the inflammatory
response, it cannot reverse inflammation once it has taken place.
For this reason, I have classed it as an anti-allergic since it
is mostly commonly taken for asthma that has a strong allergy
component.
The second two classes of asthma medications, beta-agonists and
xanthines, are both bronchodilators. Beta-agonists are
chemically related to adrenalin. They are usually taken in
inhaled form, and all but one (salmeterol) are short-acting.
The major xanthine, theophylline, is present in tea,
and is taken orally. Theophylline is chemically related to
caffeine, since caffeine is also a xanthine derivative.
Anticholinergics, the fourth class of medication, work by
blocking the contraction of the underlying smooth muscle of
the bronchi. Although used to treat asthma in Canada, the
anticholinergic ipratropium bromide (Atrovent) has not approved
by the US Food and Drug Administration for the treatment of
asthma, but is used for the treatment of COPD.
(It is interesting to note, however, that in the April 1982
issue of The FDA Drug Bulletin, the FDA states that "the
FD&C Act does not, however, limit the manner in which a
physician may use an approved drug. Once a product has been
approved for marketing, a physician may prescribe it for uses
or in treatment regimens or patient populations that are not
included in a approved labeling." The FD&C Act is the Food,
Drug, and Cosmetic Act.)
The last class, the anti-allergics, has been included because
the two anti-allergic drugs, cromolyn sodium and ketotifen, are
commonly taken for the prevention of extrinsic asthma, asthma
that has a strong allergy component. Cromolyn sodium is a
mast cell stabilizer -- it blocks the release of histamine from
mast cells, which acts to prevent asthma flares since histamine
is a very strong bronchoconstrictor. However, it isn't considered
an antihistamine because it cannot prevent the effects of
histamine once the histamine has been released from the cell.
Similarly, it blocks the release of inflammatory mediators from
the mast cell, and so prevents the inflammatory response, although
it cannot reverse inflammation once the mediators have been
released. Ketotifen fumarate (Zaditen), a non-sedating
antihistamine used mostly for the treatment of pediatric allergic
asthma, is not currently available in the United States.
For a complete listing of asthma medications, please see the
alt.support.asthma FAQ: Asthma Medications. It is posted
monthly as the companion to this general information FAQ.
Ventolin is the brand name of salbutamol, which is the WHO
(World Health Organization) recommended name for the medication.
Unfortunately, in the US this same drug is called albuterol,
leading to endless confusion. In fact, it's one of the few
drugs in which the brand name stays the same from country
to country, while the chemical name changes! Ventolin is made
in the U.S. by Allen & Hanburys, and Proventil is the same drug
manufactured by Schering. You can also get this drug in
a sustained-action tablet, called either Repetabs (by Schering,
again) or Volmax (Muro).
Yes. Quoting from the Product Information Sheet that comes
with the Serevent (salmeterol) inhaler, manufactured by
Allen & Hanburys:
"Serevent Inhalation Aerosol should not be used more frequently
than twice daily (morning and evening) at the recommend dose.
When prescribing Serevent Inhalation Aerosol, patients must be
provided with a short-acting, inhaled beta2-agonist
(e.g., albuterol) for treatment of symptoms that occur despite
regular twice-daily (morning and evening) use of Serevent."
"When patients begin treatment with Serevent Inhalation Aerosol,
those who have been taking short-acting, inhaled beta2-agonists
on a regular daily basis should be advised to discontinue their
regular daily-dosing regimen and should be clearly instructed to
use short-acting, inhaled beta2-agonists only for symptomatic
relief if they develop asthma symptoms while taking Serevent
Inhalation Aerosol."
"The safety of concomitant use of more than eight inhalations per
day of short-acting beta2-agonists with Serevent Inhalation
Aerosol has not been established."
So the above quotes seem to imply that it is okay for asthmatics
taking Serevent regularly to also use Ventolin (albuterol) as
needed, provided one doesn't need it too often.
The determination of whether a drug or substance is banned or
allowed in amateur athletic competitions is not based on whether
it is medically necessary. Rather, such a determination is based
on whether the substance in question can be performance-enhancing
and offer an unfair competitive advantage. There are several
organizations that make this determination and an athlete on an
asthmatic drug should check with his coaches, physician, and
appropriate athletic authority. Different athletic organizations
may differ on what is banned or allowed. For example, the
United States Olympic Committee (USOC) follows International
Olympic Committee guidelines for testing at Olympic events. Many
amateur athletic organizations (termed National Governing Bodies)
adopt USOC guidelines for drug testing at their events. In
contrast, the NCAA has less stringent guidelines for certain
substances used by asthmatics in during competitions. Further
complicating an athlete's understanding of the situation, some
substances that are banned in tablet form are allowed in inhaled
form.
As an example, the USOC allows inhaled forms of the beta-2 agonist
albuterol with written notification by a treating physician but
bans tablet forms of albuterol. Certain other beta-adrenergic
agonists (e.g. ephedrine, bitolterol, metaproterenol) are banned
by the USOC. An athlete who participates in an amateur athletic
event where drug testing may occur should check with his or her
coaches and physicians regarding the allowed vs. banned status of
any substance while competing. The United States Olympic
Committee Drug Hotline, (800) 233-0393, or NCAA, (800) 546-0441,
may provide information to specific questions on drugs, and
educational materials in this regard. An asthmatic should also
not assume that an over-the-counter (OTC) status of any drug
implies its allowed status in athletic competitions; many OTC
agents (e.g. combination decongestant-bronchodilators containing
ephedrine) or herbal preparations bought in food stores
(e.g. Ma Huang) contain stimulants useful for asthma but banned
in certain athletic competition settings.
Contributed by: Lyn Frumkin, M.D., Ph.D. lrfrum@u.washington.edu
MDI - metered-dose inhaler, consisting of an aerosol unit
and plastic mouthpiece. This is currently the most
common type of inhaler, and is widely available.
autohaler - MDI made by 3M which is activated by one's breath,
and doesn't need the breath-hand coordination that
a regular MDI does. Available in U.S. for Maxair.
respihaler - aerosol inhaler for Decadron. I have no idea how
this differs from the usual MDI. Available in the
U.S.
syncroner - MDI with elongated mouthpiece, used as training device
to see if medication is being inhaled properly.
Available in Canada for Intal.
accuhaler - dry powder inhaler for use with Serevent. It contains
a foil strip with 60 blisters, each containing one dose
of the drug. Pressing the lever punctures the blister,
allowing the drug to be inhaled through the mouthpiece.
Available in the UK.
diskhaler - dry powder inhaler. The drug is kept in a series of
little pouches on a disk; the diskhaler punctures
the pouch and drug is inhaled through the mouthpiece.
Currently available in Canada and UK, not in U.S.
insufflator - dry powder nasal inhaler used with Rynacrom
cartridges. Each cartridge contains one dose;
the inhaler opens the cartridge, allowing the
powder to be blown into the nose by squeezing
the bulb. Available in Canada.
rotahaler - dry powder inhaler used with Rotacaps capsules.
Each capsule contains one dose; the inhaler opens
the capsule such that the powder may be inhaled
through the mouthpiece. Available in the U.S.,
Canada, and UK for Ventolin. In Canada, Beclovent
Rotacaps are also available.
spinhaler - dry powder inhaler used with Intal capsules for
spinhaler. Each capsule contains one dose; the
inhaler opens the capsule such that the powder
may be inhaled through the mouthpiece. Available
in Canada, UK, and the U.S.
turbuhaler - dry powder inhaler. The drug is in form of a pellet;
when body of inhaler is rotated, prescribed amount of
drug is ground off this pellet. The powder is then
inhaled through a fluted aperture on top. Available
in Australia, Canada, Denmark, and Switzerland.
Some asthmatics find the dry powder inhalers more effective than
their MDI (aerosol) counterparts. It is suspected that the
aerosol or propellant in the MDI may act as an irritant to some
asthmatics, as in the following article:
J.R.W. Wilkinson et al., Paradoxical bronchoconstriction in
asthmatic patients after salmeterol by metered dose inhaler,
British Medical Journal 305 (1992) 931. The first sentence
in the conclusion is: "Bronchoconstriction after both
salmeterol and placebo by metered dose inhaler but not after
salmeterol by diskhaler suggests that the irritant is not
the salmeterol itself." . . . "The similarity in characteristics
of bronchoconstriction after beclomethasone by metered dose
inhalers implicates one or both chlorofluorocarbons . . . as
the irritant. That salbutamol caused no bronchoconstriction was
attributed to its faster onset of action opposing any
bronchoconstrictor effects of the propellants."
** However, according to the 1994 Physicians' Desk Reference,
Intal Spinhaler capsules are "contraindicated in those
patients who have shown hypersensitivity to . . . lactose."
So asthmatics who are lactose-intolerant may not have this
form of cromolyn sodium as an option.
Metered dose inhalers (MDIs) for asthma medications typically
consist of a metal aerosol canister (containing the medication and
a propellant) in a plastic sleeve with a mouthpiece. The patient
inhales one or more metered doses of a medication through the
mouthpiece. Most people find it difficult (at least initially) to
time the spraying of an MDI and the inhalation of the medicine:
the patient must exhale fully and inhale and release the metered
dose just at the beginning of the inhalation so as to draw the
medication as fully and deeply into the lungs as possible.
All too often the puffs are mis-timed and only make it part of the
way into the airways, and some of the medication is invariably
deposited into the mouth and on the back of the throat instead of
into their lungs. In addition to being less effective, this can
lead to other side effects (e.g., for inhaled steroids, an
increased potential for thrush, an oral fungal infection described
in section 2.3.3.).
Several devices have become available that address these
difficulties to varying degrees. The devices are generally
referred to as "spacers" since they place additional space between
the patient and the MDI. The medication is sprayed into the spacer
instead of the mouth. As the patient inhales, the column of
medication passes through the mouth and throat relatively quickly,
leaving little opportunity for the medication to be deposited in
the mouth or throat. This is a more efficient means of delivering
the medication to the airways where it's most needed.
The simplest kind of spacer is basically a tube. The patient
sprays the medication in one end of the tube and inhales it out
the other end. Azmacort has a simple spacer attached to it. A
cardboard tube from the core of a roll of bathroom tissue can be
used as a spacer (as long as it's clean, lint-free and germ-free).
While a simple spacer reduces the amount of medication that gets
deposited in the mouth and throat, it still requires you to
carefully time your inhalation with the discharge of the
medication to minimize the amount of the medication that escapes
from the spacer.
A "holding chamber" is a more sophisticated device. It is a sealed
chamber (once the inhaler is inserted) that traps and holds the
medication, allowing the patient to spray the medication into the
chamber and take a few seconds to inhale the medication. Since
the medication is temporarily suspended in the holding chamber,
the timing of the inhalation is not nearly as critical as with
simple spacers or no spacer. AeroChamber is a brand of holding
chamber. It's a plastic tube with a mouthpiece on one end and a
place to insert the MDI on the other. The mouthpiece has a
one-way valve built in that temporarily contains the sprayed
medication, and also allows the patient to exhale without
displacing the medication in the chamber (as without a spacer, the
patient should exhale as completely as possible before taking in
any medication, so that the medication can be inhaled as deeply as
possible).
In addition to improving the timing of the inhalation, a holding
chamber makes it possible to take in the medication more slowly
than is possible without a spacer or with a simple spacer. This
is important for the symptomatic patient, since rapid inhalation
of the medication is more likely to trigger coughing and cause the
patient to lose the medication before it has had a chance to be
absorbed.
Some spacers are clear so that you can see the puff of medicine,
and so that you can see when the medication is building up on the
inside, indicating that the spacer needs cleaning.
Spacers and holding chambers need periodic cleaning; clean
carefully, following the manufacturer's instructions so as not to
damage any delicate internal parts or allow molds or other
contaminants to be introduced.
There are special holding chambers for younger children. There's
a pediatric Aerochamber that has a mask built in; the child
breathes normally for a few seconds with the mask held over
his/her mouth and nose. This is typically used when a nebulizer
is not available or not required, and for medications that are not
available in a nebulized form, such as Beclovent or Vanceril.
There is also a device for children (and for people that have
trouble holding their breath) called an InspirEase. It's kind
of like a plastic bellows or balloon with a plastic mouthpiece.
The patient inflates it, the medicine is sprayed into it, and the
patient inhales, holds his/her breath for the count of 5 (or
whatever the doctor recommends), exhales into the device, and then
repeats. Some patients are instructed to breath slowly in and out
several times instead of holding their breath. The InspirEase
really helpful for younger children who yet aware of the
difference between breathing in and breathing out or don't yet
know how to hold their breath or breathe evenly and slowly. It
gives them immediate physical feedback, and it also has a whistle
built in to tell them when they're breathing too fast (although
they seem to like making it whistle, so it's positive
reinforcement for something that they shouldn't be doing). As the
child grows, the Inspirease becomes less effective, since it has a
limited capacity, although I've been told that it is available in
different capacities.
Knowing the difference between a simple spacer and a holding
chamber can help you use each in its proper way. If you use both a
holding chamber *and* a simple spacer (e.g., a holding chamber for
your Ventolin and the simple spacer attached to your Azmacort),
you need to remember which you're using and adjust your style
accordingly.
Spacers and holding chambers are sometimes provided by some HMOs
and covered by some insurers. A prescription is not required in
the US.
Contributed by: Mark Feblowitz mfeblowitz@GTE.com
Thrush, or thrush mouth, is the popular term for a yeast
infection (candida albicans) in the back of throat. The major
symptom of thrush is a white film located at the back of the
throat and tonsil area. It is usually cured by the use of an
antifungal mouthwash.
Thrush is a very common side effect of taking inhaled
corticosteroids, since steroids alter the local bacteria and
fungal population of the mouth, enhancing fungal growth. The
way to avoid this complication is to ensure that the back of
the throat doesn't remain coated with corticosteroid after use
of the inhaler, either by using a spacer or by rinsing the mouth
very thoroughly afterwards. Unfortunately, some people still
get it even when they are very thorough about rinsing.
Yes, Fisons is still manufacturing both the Intal Spinhaler
(a dry powder inhaler for cromolyn sodium) and the capsules
for it. Many pharmacists in the U.S. are under the impression
that it is unobtainable, probably due to the fact that the
Spinhaler was unavailable for a short time in the U.S. some
while back due to a change in formulation. During this time,
some wholesalers stopped buying the inhaler, and didn't
restock it once the Spinhaler was back in production. So
your pharmacist's regular wholesaler still may not be
carrying this product. For further information,
Fisons Corporation's number for Rx Customer Service is
(800) 334-6433.
[Maintainer's note: the Rotahaler is a dry powder inhaler
for Ventolin (albuterol), manufactured by Allen & Hanburys,
while the Spinhaler is a dry powder inhaler for Intal
(cromolyn sodium), manufactured by Fisons Corporation. Both
inhalers are available in the U.S.]
The Rotahaler and the Spinhaler are very different animals.
The Rotahaler is a pussycat, the Spinhaler a ferocious lion.
The Rotahaler is a two-part mouthpiece that you snap apart,
put a capsule in, twist, and inhale. When you twist the device,
the capsule breaks open. When you inhale, the medicine lands
in your lungs.
The Spinhaler is a three-piece device: a mouthpiece, a tiny
fan, and a cap to cover the fan. You open it, put the capsule
in a space on the fan, close it, push down then up on the cap
(this breaks the capsule) and then tilt your head back, put
the mouthpiece in your mouth, and inhale. The fan throws the
medicine into the back of your throat. Then you gag.
I don't like the propellants in MDIs, so I was highly motivated
to get a Spinhaler. It took me a month to get my drugstore to
find it, and now I must admit I'm disappointed. I tried using
an Intal capsule in the Ventolin Rotahaler, since that device
works so well, but the medicine seems to be of the wrong
consistency, and the capsule is too large for the space it
should go into.
Another difference: The Spinhaler comes in a little container
like a medicine bottle, but the lid doesn't stay on very well in
a purse. The Rotahaler comes in a little plastic case sort of
like a compact and stays shut (i.e. clean) in a purse, backpack,
or jeans pocket.
Contributed by: Paula Ford pxf3@psuvm.psu.edu
Medications taken orally almost always have a much higher
systemic concentration (concentration in your entire body)
than inhaled medications. So if the side effects are due
to systemic concentrations, then an inhaled drug is less
likely to have these side effects, or may have them much
less severely.
The idea behind an inhaler is that the full dose is delivered to
the lungs, where it is immediately absorbed by the lung tissue,
and starts to take effect locally. Excess drug may be absorbed
by the bloodstream and delivered to the rest of your body, but
this amount tends to be minimal. So your lungs receive an
immediate, high concentration of the drug, and the rest of your
body receives very little.
If you take the drug orally in tablet or capsule form, then you
need a much higher dose. The reason is that for the same amount
of drug to reach the lungs through the bloodstream, you need the
same concentration of drug in the rest of your body. For example,
most people take one or two puffs of albuterol (Ventolin or
Proventil) every four to six hours, and each puff is 90 micrograms
of albuterol. The usual dosage of Ventolin in tablets is 2-4
milligrams three or four times a day, which is something like 200
times the amount inhaled.
However, one advantage that tablets have is that the medication
may be available in a time-release format. So for a short-acting
medication like albuterol, the inhaled version might need to be
taken every four to six hours, while a extended-release tablet
such as Volmax would need to be taken only every twelve hours.
You can tell whether an MDI (metered dose inhaler) canister is
empty by taking the canister out of the mouthpiece and placing
it in a container of water. If the canister sinks, and lies
horizontally on the bottom, then it is full. If it floats
horizontally at the top, it is empty. The intermediate stages,
floating vertically at the bottom of the container, floating
vertically at the top of the container, and floating at the top
at an angle of 30 to 40 degrees, indicate that it is roughly
3/4 full, 1/2 full, and 1/4 full, respectively.
However, this technique should not be used for the cromolyn
sodium inhaler, as the package insert states that the metal
cylinder should never be immersed in water. One possible
explanation for this comes from Dr. Thomas Plaut, in the
September 1994 issue of _Prevention_ magazine (not the greatest
medical reference, but the only one I have at present): "That's
a perfect example of how fast asthma information changes. The
float test doesn't work with the cromolyn inhaler because the
powder in the MDI valve stem swells up when in comes in contact
with water. This blocks the medicine from leaving."
The last-ditch alternative, of course, is to count the doses as
you take them, and discard the canister for a new one once the
number of doses on the label has been reached. One variation
of this, for medications that are taken regularly, is to calculate
the date on which the medication will be used up, and discard the
old canister for a new one on this date.
CR - controlled release. This means that the drug has a
constant rate of release.
DR - delayed release. This generally refers to enteric-
coated tablets which are designed to release the drug
in the intestine where the pH is in the alkaline range.
ER - extended release. Dosage forms which are designed to
release the drug over an extended period of time, such
as implants which release the drug over a period of
months or years.
SA - sustained action. Used interchangeably with CR
(above), except that SA usually refers to the
pharmacologic action while CR refers to the drug
release process.
TD - time delayed. This is slightly different from DR in
that the drug release is designed to occur after a
certain period of time, such as pellets coated to a
certain thickness, multi-layered tablets, tablets
within a capsule, or double-compressed tablets.
Contributed by: Susan Graham sgraham@hpb.hwc.ca
Theophylline is commonly used as a third-line agent in the
management of asthma, after beta-agonists and anti-inflammatories.
Unfortunately, its therapeutic level is quite close to its toxic
level. This means that the dose that the asthmatic needs to get
the full benefit of the drug is not very much lower than the dose
which causes side effects which range from unpleasant to
dangerous. This would not be such a problem if there weren't
such large variations in the rate at which people metabolize
theophylline. Apparently, if a group of people are given
the same dose of theophylline, the concentration of the
drug in their bloodstreams may vary by up to a factor of
seven. Therefore, the best way to monitor that the asthmatic
is receiving the optimal amount of theophylline is to take
a blood level concentration.
The combination drugs such as Tedral and Marax commonly
contain theophylline, ephedrine, and some form of sedative
such as phenobarbital. These combination pills are no longer
commonly prescribed because the amount of theophylline in
the pill cannot be varied with respect to the other drugs.
Since there is great variation in the rate at which an
individual metabolizes theophylline, it is now considered
better to take theophylline separately, for better adjustment
of theophylline levels. In fact, Tedral is no longer
manufactured by Parke-Davis in the U.S.
Also, ephedrine is no longer considered the bronchodilator
of choice. From Drs. Haas, _The Essential Asthma Book_,
"ephedrine initiates the release of catecholamines -- including
adrenaline -- that are already stored in the body. This is
its biggest drawback. Its effects depend on the availability
of catecholamine in the body at the time it is given, and
these concentrations vary." Since much better bronchodilators
are now available, ephedrine is no longer commonly prescribed.
A nebulizer is a device that uses pressurized air to turn a
liquid medication into a fine mist for inhalation. If you've
ever received emergency treatment for asthma, they've probably
used a nebulizer on you.
The term nebulizer is often used to describe both the pump
that pressurizes the air, and the part that holds and
"nebulizes" the medication. There are hand-held nebulizer
units and ones with masks that you strap onto your face.
The pressurized air typically comes from a portable pump unit
that internally consists of a motor-driven air pump that
resembles the fancier types of aquarium pumps. It forces air
through a plastic tube into the plastic nebulizer unit. Inside,
the nebulizer unit acts much like a perfume atomizer, creating
a fine mist that is directed either through a tube that you
inhale through or a mask that directs the mist into your nose
and mouth.
Since the nebulizer takes a few minutes to deliver the medication,
you inhale it over a longer period of time than if you were using
an inhaler. This can really help, especially if your passages are
not fully open and you're taking a bronchodilator. As you breathe
the medication, your lungs can gradually accept more and more of
the medication. In addition to the medication, many people find
the accompanying mist (typically a sterile saline solution) to be
soothing.
For very young children, the nebulizer is the only practical
means of administering inhaled medications. Older children and
adults have the options of using inhalers and a variety of
spacers to make the timing a bit easier. The doctor overseeing
the treatment decides which is the most effective/appropriate
delivery mechanism.
At least in Massachusetts, the nebulizer pump unit, the
hand-held nebulizers, the medications, and the sterile saline
inhalation solution are all prescription items. Replacement
parts for the pumps are not available to the general public
(if there are sources, I'd like to hear about them).
The portable nebulizer pump units cost little ($100-$300)
relative to the cost of an emergency room visit, so some health
plans / insurers provide them to patients for times when an
asthma episode is "manageable but not dangerous." This seems to
be a trend in the management of pediatric asthma.
Our family has been able to successfully avoid a few trips to
the ER, and have even been able to head off some more severe
allergic asthma episodes with early intervention. After a few
rather gruesome visits to the Mass. General Hospital's waiting
room on a Saturday night, we welcome opportunity to treat our
children at home, when it's safe. We tend to go in to the doctor
or ER for the more severe episodes or those that don't respond
well enough to early intervention.
Contributed by: Mark Feblowitz mfeblowitz@GTE.com
Aspirin can trigger an asthma attack in approximately one in
five asthmatics. This is especially common in those asthmatics
who also have nasal polyps. As acetominophen (Tylenol) doesn't
have this effect, it may be used as an alternative for anyone
who suspects that they might have aspirin sensitivity.
Cough medicines should also be treated with caution. In general,
suppressing a productive cough (one which is bringing up mucus)
is not a good idea, since the mucus can obstruct the airways
and also irritate them further. Also, in _Asthma: Stop
Suffering, Start Living_, the authors caution that "prescription
cough suppressants (including those with codeine) are potentially
dangerous for asthmatics. They may make you sleepy and reduce
your breathing effort. They may also dry out your secretions,
making mucus harder to raise."
Antihistamines, however, should not pose a problem for most
asthmatics, in spite of many warning labels. In _Children with
Asthma_, Dr. Plaut states, "Most asthma experts see no problems
with using antihistamines between or during asthmatics . . .
Theoretically these drugs might dry up the mucus in the
windpipes, thus making it harder to cough it up, but this has
never been proved."
Asthmatics taking theophylline should be careful when taking any
of the following medications: the ulcer medications cimetidine
(Tagamet) and troleandomycin (TAO), beta-blocker drugs such as
propranolol, and the antibiotics erythromycin and ciprofloxacin.
These medications may increase the concentration of theophylline
in the bloodstream, possibly even to the toxic level (see
section 2.4.1). People taking theophylline should be alert for
signs of possible toxicity such as rapid or irregular heartrate,
nervousness, or nausea, when taking these medications. In fact,
asthmatics taking theophylline should check with their physician
before taking any OTC medication, as the list of drugs, including
antihistamines, which affect theophylline levels is almost
endless.
Beta-blockers, usually taken for hypertension, can pose problems
even for those asthmatics not taking theophylline. Beta-blockers
work by blocking the hormone adrenalin, but as adrenalin and
other adrenergic drugs help keep airways dilated, the use of
beta-blockers may aggravate asthma symptoms.
Please see the alt.support.asthma Reading/Resource List. It
is maintained by Lynn Short <lfshort@europa.com>, and is
posted periodically to alt.support.asthma, alt.med.allergy,
sci.med, and misc.kids. I highly recommend it!
I also strongly recommend the NHLBI Executive Summary:
Guidelines for the Diagnosis and Management of Asthma (full
citation in References section). It may be ordered by calling
(301) 251-1222 and asking for publication number 94-3042A.
When I ordered it, and asked that it be sent to a US address,
there was no charge.
The newsgroup misc.kids also has an allergy and asthma FAQ,
which is available either by following the instructions
posted on misc.kids.info, or by accessing the World Wide Web,
<URL: http://www.cs.unc.edu/~kupstas/FAQ.html>.
In addition, I maintain an Asthma and Allergy WWW Resources Page,
<URL: http://www.cco.caltech.edu/~wrean/resources.html>, and
two FAQs on allergies. For information on how to access these
allergy FAQs, please see section 3.1.
The two asthma FAQs I maintain,
alt.support.asthma FAQ: Asthma -- General Information
alt.support.asthma FAQ: Asthma Medications
are posted once a month, on or about the 17th, to the following
newsgroups: alt.support.asthma, alt.med.allergy, sci.med,
alt.answers, sci.answers, and news.answers.
If these FAQs have already expired at your site, you can get
them by sending mail to mail-server@rtfm.mit.edu, with a blank
subject line, and with one or both of the following commands
in the message:
send usenet/news.answers/medicine/asthma/general-info
send usenet/news.answers/medicine/asthma/medications
Alternatively, if you're really in a hurry, you can get them via
anonymous ftp from rtfm.mit.edu, with the path names: