NR 507 Week 7 Outline – Advanced Pathophysiology | Latest 2025 Edition | Comprehensive Guide with Verified Solutions

NR 507 Week 7 Outline – Advanced Pathophysiology |
Latest 2025 Edition | Comprehensive Guide with Verified
Solutions


Chapter 17: Drugs Affecting the Respiratory System
Bronchodilators

 BETA2-RECEPTOR AGONISTS
o Albuterol (ProAir, Ventolin, Proventil) *most common
o metaproterenol (Alupent), terbutaline (Brethine, Brethaire), bitolterol
(Tornalate), pirbuterol (Maxair), and levalbuterol (Xopenex) *short acting
o arformoterol (Brovana), formoterol (Foradil), indacaterol (Arcapta), and
salmeterol (Serevent) *long acting

Pharmacodynamics

 act on the smooth muscle of the bronchial tree to reverse bronchospasm, thereby
decreasing airway resistance and residual volume and increasing vital capacity
and airflow.
 stimulate beta2 adrenergic receptors in the lungs to increase production of cyclic
adenosine monophosphate (cAMP) by activation of adenyl cyclase, the enzyme
that catalyzes the conversion of adenosine triphosphate (ATP) to cAMP.
 Increased cAMP concentrations relax bronchial smooth muscle and inhibit
release of mediators of immediate hypersensitivity from cells, especially from the
mast cells
effects
 all of the currently available preparations have some effects on other body
systems (cardiovascular system, skeletal muscles, and CNS)
o vasodilationdecrease in diastolic BP reflux tachycardia
o increased heart rate

Contraindications & Precautions

 Contraindications
o Cardiac arrhythmias associated with tachycardia
o heart block caused by digitalis intoxication
o angina
o narrow-angle glaucoma
o organic brain damage (epinephrine only)
o shock during general anesthesia with halogenated agents

,  patients with hypertension, ischemic heart disease, coronary insufficiency,
congestive heart failure, and a history of stroke and/or cardiac arrhythmias
should be monitored closely for adverse effects during administration
 patients with DM, there is a potential drug-induced hyperglycemia that may result
in loss of diabetic control insulin dosage may need to be increased
 patients with hyperthyroidism, adverse reactions are more likely to occur
 Patients taking digoxin require close monitoring when albuterol is started
because it increases the volume of distribution of digoxin and can cause up to a
30% decrease in blood digoxin levels.
 FDA released a safety announcement regarding LABAs (Long acting beta
agonists)
o To ensure the safe use of these products:
 Single-ingredient LABAs should only be used in combination with
an asthma controller medication; they should not be used alone.
 should only be used long-term in patients whose asthma cannot be
adequately controlled on asthma controller medications.
 should be used for the shortest duration of time required to achieve
control of asthma symptoms and discontinued, if possible, once
asthma control is achieved. Patients should then be maintained on
an asthma controller medication.
 Pediatric and adolescent patients who require the addition of a
LABA to an inhaled corticosteroid should use a combination
product containing both an inhaled corticosteroid and a LABA, to
ensure compliance with both medications

ADR

 usually transient temporary reduction in dose may alleviate some of the side
effects
 palpitations
 supraventricular & ventricular ectopic beats
 CNS excitation  tremors, dizziness, shakiness, nervousness, and restlessness
 headache

Drug interactions

 digitalis glycosides increased risk of cardiac arrhythmiasmonitor ECG
carefully
 Beta agonists used with beta-adrenergic blocking agents (including ophthalmic
preparations) may result in mutual inhibition of therapeutic effects
 Tricyclic antidepressants and MAOIs used with albuterol, metaproterenol, or
terbutaline may potentiate the effects of the bronchodilator on the vascular
system.

,  Hypokalemia or electrocardiogram changes may be seen with coadministration
of the beta agonists with drugs that lower the potassium level, such as diuretics.

Clinical Use and Dosing

 Bronchospasm: most often associated with asthma, bronchitis (acute or
chronic), and COPD
o dose of albuterol metered-dose inhaler (MDI) in children over age 4 years
and adults is two puffs every 4 to 6 hours albuterol (Ventolin, Proventil)
o delivered via nebulizer for children over age 12 years as well as for adults
is 2.5 mg (0.5 mL) in 2 mL normal saline; for younger children up to 15 kg,
the dose is 0.1 to 0.15 mg/kg per dose.
o Inhaled forms of albuterol may be repeated once after 5 to 10 minutes, up
to 2 times (three doses total) during exacerbations.
o oral albuterol dose in adults is 2 to 4 mg 3 or 4 times a day, up to a
maximum of 32 mg/day. For children aged 6 to 12, 2 mg albuterol 3 or 4
times a day may be prescribed, (oral albuterol is rarely used in children)
o Aformoterol is not approved for use in children and should not be used for
acute asthma exacerbation
o recommended dose of levalbuterol (Xopenex) inhalation solution in
adolescents over age 12 years and adults is 0.63 mg 3 times a day, every
6 to 8 hours. Dosing for children aged 6 to 11 is 0.31 mg 3 times a day per
the manufacturer's label, with routine dosing not to exceed 0.63 mg 3
times a day.
o Salmeterol is not to be used for short-term bronchospasm relief. If
prescribing salmeterol for persistent asthma, the drug must be prescribed
in conjunction with an inhaled corticosteroid or other asthma controller
medication
o Hospital admission may be avoided by the addition of ipratropium to the
treatment regimen in cases of exacerbation seen in the clinic or
emergency department.
o Ipratropium is the bronchodilator of choice in patients who are taking beta
blockers or who do not tolerate beta2 agonists.
 Exercise-Induced Bronchospasm:
o used just before exercise can prevent exercise-induced bronchospasm
o inhaled albuterol or other short-acting beta2 agonist and salmeterol
o albuterol MDI to prevent EIB is two puffs 15 minutes prior to exercise,
should prevent EIB for 2 to 3 hours.
o The dose of salmeterol is two puffs 30 to 60 minutes prior to exercise.
should prevent EIB for 10 to 12 hours.
o Salmeterol and other long-acting beta2 agonists have a shortened duration
of action if used on a daily basis

Rational Drug Selection

,  the only short-acting bronchodilators that can be prescribed for children under
age 4 are albuterol and metaproterenol.
 Levalbuterol is labeled to be used in children older than age 4
 Albuterol is by far the most often used medication in clinical practice and is safe
to use even in infants
 albuterol is the least expensive, especially if a generic formula is prescribed

Patient Education

 Overuse of bronchodilators will lead to increased adverse effects
 using less than prescribed may lead to increased bronchospasm and decreased
pulmonary function.
 MDILearning to coordinate the release of the medication from the inhaler with a
deep breath is difficult
 patient should first exhale and then tilt the head slightly back and place the
inhaler mouthpiece either about 2 inches from the open mouth or between the
open lips. While inhaling, the patient should press down on the canister, breathe
in slowly and deeply, and hold his or her breath for 10 seconds (count of 10) or
as long as comfortable.
 If two puffs are prescribed, then the patient should wait at least 1 full minute
between inhalations.
 The Foradil capsule is placed into the aerolizer, then the aerolizer is squeezed to
break the capsule. The patient inhales the medication.Patients should receive
clear instructions not to swallow the capsule
 The patient needs to self-monitor respiratory status with a peak flowmeter to
determine the effectiveness of the prescribed medication.
 The patient should avoid or quit smoking.
 The patient should avoid environmental triggers for asthma at home, work, and
school.

Xanthine Derivatives

 Methylxanthines
o theophylline
o aminophylline
o caffeine

Pharmacodynamics

 believed to be mediated by selective inhibition of specific phosphodiesterases
(PDEs).  produces an increase in cAMP,  leads to bronchial smooth muscle
and pulmonary vessel relaxation
 Theophylline and caffeine have an impact on most of the major body systems.
o powerful CNS stimulants, often causing insomnia and excitability