Standard Treatment of Asthma with the Latest Treatment Guidelines 2020
Standard Treatment of Asthma with the Latest Treatment Guidelines 2020
A.
Pharmacologic Agents
Asthma
medications can be divided into two categories:
Quick-relief
(reliever)
medications
that act principally by direct relaxation of bronchial smooth muscle,thereby
promoting prompt reversal of acute airflow obstruction to relieve accompanying symptom.
Long-term
control (controller)
medications
that act primarily to attenuate airway inflammation and that are taken daily
independent of symptoms to achieve and maintain control of persistent asthma.
Anti-inflammatory agents, long-acting bronchodilators, and leukotriene
modifiers comprise the important long-term control medications.
Most asthma
medications are administered by inhalation or orally. Inhalation of an appropriate
agent results in a more rapid onset of pulmonary effects as well as fewer systemic
effects compared with oral administration of the same dose. Proper inhaler technique
and the use of an inhalation chamber (a “spacer”) with metered-dose inhalers (MDIs) decrease oropharyngeal
deposition and improve drug delivery to the lung.Nebulizer therapy is reserved
for patients who are acutely ill and those who cannot use inhalers because of
difficulties with coordination, understanding, or cooperation.
Quick-relief
medications for asthma.
Beta-adrenergic
agonists
Beta-agonists
are divided into short-acting beta-agonists (SABAs) and long-acting
beta-agonists (LABAs). SABAs, including albuterol, levalbuterol, bitolterol,
pirbuterol, and terbutaline are the mainstays of reliever or rescue therapy for
asthma patients; all asthmatics should have immediate access to a SABA. SABAs
are the most effective bronchodilators during exacerbations and provide
immediate relief of symptoms. Administration before exercise effectively
prevents exercise-induced bronchoconstriction.Inhaled SABA therapy is as
effective as oral or parenteral therapy in relaxing airway smooth muscle and
improving acute asthma and offers the advantages of rapid onset of action (less
than 5 minutes) with fewer systemic side effects. Repetitive administration
produces incremental bronchodilation.
LABAs provide
bronchodilation for up to 12 hours after a single dose. Salmeterol and
formoterol are the LABAs available for asthma in the United States. They are administered
via dry powder delivery devices. They are indicated for long-term prevention of
asthma symptoms (including nocturnal symptoms) and for prevention of exercise-induced
bronchospasm. When added to low and medium daily doses of inhaled corticosteroids.
The efficacy of combined inhaled corticosteroid and LABA therapy has led to the
marketing of combination medications that deliver both agents simultaneously.
Combination inhalers containing formoterol and budesonide have shown efficacy
in both rescue (given formoterol’s short time to onset)
and maintenance (budesonide).
Corticosteroids
Corticosteroids
are the most potent and consistently effective anti-inflammatory agents
currently available. They decrease both acute and chronic inflammation,
resulting in reduced symptoms and improved lung function. These agents may also
potentiate the action of beta-adrenergic agonists.
Inhaled
corticosteroids are
preferred, first-line agents for all patients with persistent asthma. Patients
with persistent symptoms or asthma exacerbations who are not taking an inhaled
corticosteroid should be started on one. The most important determinants of
agent selection and appropriate dosing are the patient’s
status and response to treatment. Dosages for inhaled corticosteroids vary
depending on the specific agent and delivery device. For most patients, twice-daily
dosing provides adequate control of asthma. Once-daily dosing may be sufficient
in selected patients. Maximum responses from inhaled corticosteroids may not be
observed for months. The use of an inhalation chamber coupled with mouth
washing after inhaled corticosteroid use decreases local side effects (cough,
dysphonia, oropharyngeal candidiasis) and systemic absorption. Dry powder
inhalers (DPIs) are not used with an inhalation chamber. Systemic effects
(adrenal suppression, osteoporosis, skin thinning, easy bruising, and
cataracts) may occur with high-dose inhaled corticosteroid therapy.Many
combination inhalers with inhaled corticosteroid/LABA offer convenient treatment
of persistent asthma.
Systemic
corticosteroids (oral or parenteral) are most effective in achieving prompt control of asthma
during exacerbations. Systemic corticosteroids are effective primary treatment
for patients with moderate to severe asthma exacerbations and for patients with
exacerbations who do not respond promptly and completely to inhaled SABA
therapy. These medications speed the resolution of airflow obstruction and reduce
the rate of relapse. Delays in administering corticosteroids may result in
delayed benefits from these important agents. In patients with refractory, poorly
controlled asthma, systemic corticosteroids may be required for the long-term
suppression of symptoms. Repeated efforts should be made to reduce the dose to
the minimum needed to control symptoms. Alternate-day treatment is preferred to
daily treatment. Concurrent treatment with calcium supplements and vitamin D
should be initiated to prevent corticosteroid-induced bone mineral loss in long-term
administration. Bone mineral density testing after 3 or more months of systemic
corticosteroid lifetime use can guide the use of bisphosphonates for treatment of
steroid-induced osteoporosis. Rapid discontinuation of systemic corticosteroids
after long-term use may precipitate adrenal insufficiency.
Estimated comparative daily dosages for inhaled corticosteroids for asthma.
Anticholinergics
Anticholinergic
agents reverse vagally mediated bronchospasm but not allergen- or
exercise-induced bronchospasm. They may decrease mucus gland hypersecretion.
Both short-acting muscarinic agents (SAMAs) and long-acting muscarinic agents (LAMAs)
are available. Ipratropium bromide, a SAMA, is less effective than SABA for
relief of acute bronchospasm, but it is the inhaled drug of choice for patients
with intolerance to SABA or with bronchospasm due to beta-blocker medications.
Ipratropium bromide reduces the rate of hospital admissions when added to inhaled
SABAs in patients with moderate to severe asthma exacerbations.One study showed
that the addition of once-daily tiotropium to an inhaled corticosteroid is as
effective as twice-daily salmeterol.
Leukotriene
modifiers
Leukotrienes
are potent mediators that contribute to airway obstruction and asthma symptoms
by contracting airway smooth muscle, increasing vascular permeability and mucus
secretion, and attracting and activating airway inflammatory cells. Zileuton is
a 5-lipoxygenase inhibitor that decreases leukotriene production, and
zafirlukast and montelukast are cysteinyl leukotriene receptor antagonists.
Phosphodiesterase
inhibitor
Theophylline
provides mild bronchodilation in asthmatic patients. Theophylline also has
anti-inflammatory and immunomodulatory properties, enhances mucociliary
clearance, and strengthens diaphragmatic contractility.Sustained-release
theophylline preparations are effective in controlling nocturnal symptoms and
as added therapy in patients with moderate or severe persistent asthma whose
symptoms are inadequately controlled by inhaled corticosteroids. When added to an
inhaled corticosteroid, theophylline may allow equivalent control at lower corticosteroid
doses.
Mediator
inhibitors
Cromolyn
sodium and nedocromil are long-term control medications that prevent asthma
symptoms and improve airway function in patients with mild persistent or
exercise-induced asthma. These agents modulate mast cell mediator release and
eosinophil recruitment and inhibit both early and late asthmatic responses to allergen
challenge and exercise-induced bronchospasm. They can be effective when taken
before an exposure or exercise but do not relieve asthmatic symptoms once present.
The clinical response to these agents is less predictable than to inhaled corticosteroids.
Nedocromil may help reduce the dose requirements for inhaled corticosteroids.
Both agents have excellent safety profiles.
B.
Desensitization
Immunotherapy
for specific allergens may be considered in selected asthma patients who have
exacerbations when exposed to allergens to which they are sensitive and when
unresponsive to environmental control measures or other therapies. Studies show
a reduction in asthma symptoms in patients treated with single-allergen
immunotherapy.Because of the risk of immunotherapy-induced bronchoconstriction,
it should be administered only in a setting where such complications can be
immediately treated.
C.
Vaccination
Patients
with asthma should receive pneumococcal vaccination (Pneumovax 23) and annual influenza
vaccinations. Inactive vaccines (Pneumovax) are associated with few side
effects, but the use of the live attenuated influenza vaccine intranasally may
be associated with asthma exacerbations in young children.
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