Asthma Treatment cont..
The specific medical
treatment recommended to patients with asthma
depends on the severity of their
illness and the frequency of their symptoms. Specific treatments for
asthma are broadly classified as relievers, preventers and emergency
treatment.
Bronchodilators are recommended for
short-term relief in all patients. For those who experience occasional
asthma attacks, no other medication is needed. For those with mild
persistent disease (more than two attacks a week), low-dose inhaled
glucocorticoids—or alternatively, an oral leukotriene modifier, a
mast-cell stabilizer, or theophylline—may be administered.
For those who suffer daily attacks, a
higher dose of glucocorticoid in conjunction with a long-acting inhaled
β-2 agonist may be prescribed; alternatively, a leukotriene modifier or
theophylline may substitute for the β-2 agonist. In severe asthmatics,
oral glucocorticoids may be added to these treatments during severe
attacks.
For those in whom exercise can trigger an asthma attack
(exercise-induced asthma), higher levels of ventilation and cold, dry
air tend to exacerbate attacks. For this reason, activities in which a
patient breathes large amounts of cold air, such as cross-country
skiing, tend to be worse for asthmatics, whereas swimming in an indoor,
heated pool, with warm, humid air, is less likely to provoke a response.
Relief asthma
medication
A typical asthma inhaler, of Serevent (salmeterol)
Symptomatic control of episodes of wheezing and shortness of breath is
generally achieved with fast-acting bronchodilators. These are typically
provided in pocket-sized, metered-dose inhalers (MDIs—see the image to
the right).
In young asthma sufferers, who
may have difficulty with the coordination necessary to use inhalers, or
those with a poor ability to hold their breath for 10 seconds after
inhaler use (generally the elderly), an asthma spacer (see top image) is
used. The spacer is a plastic cylinder that mixes the medication with
air in a simple tube, making it easier for patients to receive a full
dose of the drug and allows for the active agent to be dispersed into
smaller, more fully inhaled bits. A nebulizer—which provides a larger,
continuous dose—can also be used. Nebulizers work by vapourizing a dose
of medication in a saline solution into a steady stream of foggy vapor,
which the patient inhales continuously until the full dosage is
administered. There is no clear evidence, however, that they are more
effective than inhalers used with a spacer. Nebulizers may be helpful to
some patients experiencing a severe attack. Such patients may not be
able to inhale deeply, so regular inhalers may not deliver medication
deeply into the lungs, even on repeated attempts. Since a nebulizer
delivers the medication continuously, it is thought that the first few
inhalations may relax the airways enough to allow the following
inhalations to draw in more medication.
Relievers include:
Short-acting, selective beta2-adrenoceptor agonists (salbutamol [albuterol],
levalbuterol, terbutaline, bitolterol, pirbuterol, procaterol, fenoterol,
reproterol). Tremors, the major side effect, have been greatly reduced
by inhaled delivery, which allows the drug to target the lungs
specifically; oral and injected medications are delivered throughout the
body. There may also be cardiac side effects at higher doses (due to
Beta-1 agonist activity), such as elevated heart rate or blood pressure;
with the advent of selective agents, these side effects have become less
common. Patients must be cautioned against using these medicines too
frequently, as with such use their efficacy may decline, producing
desensitization resulting in an exacerbation of symptoms which may lead
to refractory asthma and death.
Older, less selective adrenergic agonists, such as inhaled epinephrine
and ephedrine tablets—both of which, unlike other medications, are
available over the counter in the US under the Primatene brand. Cardiac
side effects, although uncommon, occur more often with the less
selective drugs. They also provide a shorter period of relief than the
selective bronchodilators. Nowadays, they are usually avoided in
patients with heart disease. In emergencies, these drugs were sometimes
administered by injection. Their use in this situation has declined.
Anticholinergic medications, such as ipratropium bromide may be used
instead. They have no cardiac side effects and thus can be used in
patients with heart disease; however, they take up to an hour to achieve
their full effect and are not as powerful as the β2-adrenoreceptor
agonists.
Emergency asthma
treatment
When an asthma attack is
unresponsive to a patient's usual medication, other treatments are
available to the physician or hospital:
oxygen to alleviate the hypoxia (but not the asthma per se) that results
from extreme asthma attacks;
nebulized salbutamol (a short-acting beta-2-agonist), often combined
with ipratropium (an anticholinergic);
systemic steroids, oral or intravenous (prednisone, prednisolone,
methylprednisolone, dexamethasone, or hydrocortisone)
other bronchodilators that are occasionally effective when the usual
drugs fail:
nonspecific beta-agonists, injected or inhaled (epinephrine, isoetharine,
isoproterenol, metaproterenol);
anticholinergics, IV or nebulized, with systemic effects (glycopyrrolate,
atropine);
methylxanthines (theophylline, aminophylline);
inhalation anesthetics that have a bronchodilatory effect (isoflurane,
halothane, enflurane);
the dissociative anesthetic ketamine, often used in endotracheal tube
induction
magnesium sulfate, intravenous; and
intubation and mechanical ventilation, for patients in or approaching
respiratory arrest.
Asthma Information
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